TiO₂ has attracted enormous interest as the best semiconductor for the photodegradation of organic pollutants in water. Compared to the other catalysts used for heterogeneous UV/oxidation process, TiO₂ photocatalyst has been regarded as an efficient photocatalyst due to superior photocatalytic activity, thermal and chemical stability, high photostability on wide pH range and non-toxic structure.Despite all of these advantages, anatase TiO₂ nanoparticles have two major drawbacks which reduce its efficiency and usefulness. The first of these drawbacks is the limited usage of visible light due to wide band gap energy (3.2 eV) of TiO₂. The other one is the short recombination time of photogenerated electron-hole pairs (10-100 ns). Therefore, overall quantum efficiency is reduced due to the shortening lifetime of electron-hole pairs.Nowadays, the majority of scientific researches about TiO₂ photocatalyst aims to reduce the effects of these disadvantages. In recent years, TiO₂ photocatalyst surface is functionalized with various methods for this purpose such as metal deposition, integration with metal oxides, dye anchoring, doping/co-doping, forming hybrids with nanomaterials and using surface adsorbates.Therefore, functionalization of TiO₂ samples with a functional group is an effective method..Several important studies were focused on the adsorption of organic molecules (the catechol derivatives and other phenolic compounds) on TiO₂ surfaces. However, very few studies have used gallic acid as an adsorbent for TiO₂ photocatalyst. Therefore, the adsorption mechanism of gallic acid on TiO₂ surface is not well understood.In this study, the adsorption mechanism of gallic acid on Ti02 surface was investigated in detail. TiO₂ nanoparticles were successfully synthesized via hydrothermal method. Conditions of the synthesis were optimized using the fractional factorial design with three-variables (optimum reaction temperature, reaction time and ratio). According to the TEM micrographs, average size of TiO₂ nanoparticles was in the range of 25–35 nm and the particles have tetragonal crystal structure. Synthesized nanoparticles were functionalized with Gallic acid and ammonium floride as an organic and inorganic surface adsorbent respectively.FTIR and XPS analysis results of gallic acid adsorbed TiO₂ nanoparticles show that gallic acid may be bonded to TiO₂ surface through carboxyl groups. Fluorine atoms were connected to the TiO₂ surface via ligand exchange with the hydroxyl groups of the TiO₂ and this situation was proved with XPS analysis results of fluorine adsorbed TiO₂. XRF analysis results show that C and F which bonded to TiO₂ surface increased with increasing the amounts of adsorbents used on different functionalization experiments.The photo-activity of the functionalized nanoparticles were measured on the decolorisation of methylene blue as a model pollutant by UV-Vis spectrophotometer. It was found that the fluorinated TiO₂ with 0.2 g NH₄F exhibits significantly higher photocatalytic activity than the unfunctionalised counterpart and commercially available Degussa P25. On the other hand, while photocatalytic activity of the particles decreases, adsorption capability of the particles increases with the increasing of Gallic acid amount.
This study was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) under project 1001 - Scientific and Technological Research Programme. The authors gratefully thank TUBITAK for funding their research project (Project No: 113Z635).
Jewellery is part of human history for many centuries and was made in many variants. One of Slavic female jewellery was characteristic metallic S-shaped-end ring jewel (SERJ). SERJs were usually worn near their temple skull bones. Laser desorption/ionization mass spectrometry (LDI-MS) and X-ray photoelectron spectroscopy (XPS) allows to effectively study organic compounds profile on the SERJs surface and helps us to understand the way they were used - whether as an attached part of a headdress or knitted directly into braids of hair.
SERJ sample was discovered in a grave during rescue archaeological research in Dětkovice, in the Czech Republic (2009). It can be roughly dated to Middle Ages (10th–11th century). Firstly, the organic matter on sample surface was studied directly with XPS technique and then directly with laser desorption/ionization mass spectrometry (some organic-like pieces were removed and fixed on MALDI plate). Besides also mass spectrometry imaging was used to study the distribution of analytes on the SERJs surface. Synapt G2-S high resolution tandem mass spectrometer (Waters, USA) and XPS spectrometer VersaProbe II (PHI, USA) was used for all experiments.
XPS direct analysis of organic-like fibres adhered to the SERJs surface confirmed the presence of a number of elements. Signals of C, O, N, Ca, Cu, P and Si were found and their chemical forms tentatively elucidated. LDI-MS analysis of the organic material revealed the presence of dehydrated sugar chains in the form of sodium and potassium adducts. Signals at m/z 347.0978 (C12H20O10Na⁺), 509.1538 (C18H30O15Na⁺), 671.1985 (C24H40O20Na⁺), 833.2597 (C30H50O25Na⁺) and 995.3055 (C36H60O30Na⁺) were found in positive ionization mode and they were ascribed to sodium adducts of saccharide chains. Signals at m/z 201.0052 (C6H10O5K⁺), 363.0626 (C12H20O10K⁺), 525.1253 (C18H30O15K⁺), 687.1818 (C24H40O20K⁺), 849.2378 (C30H50O25K⁺), found also in positive ionization mode were suggested to potassium adducts of saccharide chains. Some of those signals and their mass distribution on organic fiber-like area on SERJ surface were confirmed with MS Imaging. In negative ionization mode, signals at m/z 403.0685 (C12H20O13P⁻), 549.1299 (C18H30O17P⁻), 565.1221 (C18H30O18P⁻), 711.1800 (C24H40O22P⁻), 727.1711 (C24H40O23P⁻), 873.2339 (C30H50O27P⁻) and 889.2366 (C30H50O28P⁻) were identified as phosporylated dehydrated saccharide chains.
The obtained data confirm the presence of cellulose residues localized on fiber-like material on SERJ. According to our last results and three years experience with metallic artefacts analysis (i.e. other SERJs, metallic Sun Symbol etc. studied in various chorological and chronological contexts) we suggest that the SERJs were attached to the headdress by a plant thread. Comprehensive interpretation of the data from the multimodal research based on XPS and LDI-MS in archaeological context is now in progress.
Authors gratefully acknowledge the support by the Czech Science Foundation (grant No. 17-17346S).
A magnetic Fe3O4/MgAl-layered double hydroxide (LDH) composite was prepared by conventional co-precipitation in the dispersed Fe3O4 suspension. The morphological and structural properties of the obtained Fe3O4/MgAl-LDH was characterized by X-ray diffraction, scanning electron microscopy coupled with energy dispersive spectroscopy, transmission scanning electron microscopy and Brunauer-Emmett-Teller. The adsorption performance of the adsorbent was evaluated using isotherm and kinetic models. The equilibrium data were represented well by the Langmuir adsorption isotherm and pseudo-second order kinetic equation The maximum adsorption capacities of gold and iridium were found to be 119 mg g−1 for gold and 112 mg g−1 for iridium. The selectivity of the nanoadsorbent in the presence of diverse common ions and other platinum group metals (PGMs) were investigated. The adsorbent demonstrated relatively great selectivity towards Au and Ir ions. The recovery of Au and Ir ions was achieved using 0.10 M HCl–0.20 M thiourea solution. Recoveries ranging from 98% to 99.6% were obtained and the adsorbent was found to be reusable up to ten cycles of adsorption/ desorption and regeneration. The nanocomposite was successfully applied for recovery of Au in soil samples collected from a gold mine.
Ammonium dinitramide (ADN) is an ionic compound containing ammonium cation and dinitramide anion. ADN is a strong, environmentally friendly oxidizer developed in the 1990s for use in composite solid rocket propellants. ADN acts as an excellent solid rocket oxidizer with a slightly higher specific impulse than ammonium perchlorate and, more importantly, does not release hydrogen chloride fumes. ADN is thought to replace today's dominant oxidizer ammonium perchlorate . Despite there are publications of the structural features of ADN, there are very few studies on the determination methods and no nanoparticle based colorimetric sensor exist. In this context, on this work has been developed a sensitive and easily applicable sensor that will allow quantification of the target propellant energetic material ADN and to determine it in the presence of other explosives. The principle of determination of the developed spectrophotometric method is the detection of nitrite formed by ADN degradation under UV light in a basic solution by a nanoparticle based colorimetric sensor [2,3]. Nitrite ion formed by ADN is used for forming colored product AuNP-4-ATP (gold nanoparticle modified with 4–aminothiophenol (4-ATP)) individually along with a coupling reagent N-(1-naphthyl)ethylene diammine (NED) for forming azo dye. Finally, the absorbance of the colored product is measured. The analytical performance characteristics of the developed method for the analytes as molar absorptivity (ε); limit of detection (LOD) and limit of quantification (LOQ) are as follows: ɛ=4.91x104 L mol-1 cm-1; LOD= 0.092 mg L-1 and LOQ=0.307 mg L-1. The developed method was also used for tetryl determination. Interference effects of nitroaromatic nitramine and nitrate esters based energetic materials like TNT, Tetryl, RDX, HMX and PETN to the ADN determination method was investigated. The developed sensor successfully has determined ADN in the presence of TNT, RDX, HMX and PETN in 50-fold more concentration. To remove its interference effect on ADN determination, TNT was removed by solvent extraction . The base concentration was reduced to reduce the interference effect of other explosives. Additionally, the interference effects of various anions and cations commonly found in soil such as Cl-, NO3-, SO42-, K+, Mg2+, and Ca2+ were investigated as well. The developed method is statistically validated against voltammetric method existing in the literature using t- and F- tests.
Highly sensitive nanosensors such as graphene oxide/ platinum-iridium nanohybrid, carboxylic acid functionalized multiwalled carbon nanotubes (GO/Pt-Ir/MWCNT-COOH) and amine functionalized multiwalled carbon nanotubes (GO/Pt-Ir/MWCNT-NH2) modified glassy carbon electrode were developed for the determination of 5-hydroxytryptamine receptor agonist, Eletriptan. Graphene oxide/platinum-iridium nanohybrid was synthesized using sonication method and then characterized by spectroscopic and microscopic methods such as Raman, TEM, HRTEM, XPS, and XRD. The prepared nanohybrids modified on glassy carbon electrodes were well characterized and applied for electrochemical determination of Eletriptan. The significant enhancement of the oxidation peak current of Eletriptan was observed in GO/Pt-Ir/MWCNT-COOH as a best nanosensor in all prepared ones. The pH, scan rate and the amount of GO/Pt-Ir/MWCNT-COOH were also optimized for Eletriptan analysis. After obtaining of the optimum conditions, the identification of Eletriptan was performed between the linear range of 1×10⁻⁷ M and 4×10⁻⁶ M with a detection limit of 6.1×10⁻⁹ M. The developed method was successfully applied for the determination of the drug in tablets with acceptable recoveries. Moreover, it can be elicited that, in electrochemical studies, electroactive interferences from the tablet excipients did not interfere with the results.
Ixodic ticks transmit such dangerous diseases as tick-borne viral encephalitis and Lyme disease. One of the modern means of individual protection against ticks is clothing made from fabric impregnated with pyrethroids.
In this work, a method for the quantitative determination of permethrin and cypermethrin in impregnated tissues is proposed. Earlier, extraction with toluene and methanol was used for these purposes. However, during the reproduction of the method, the obtained values coefficient of extraction for cypermethrin did not exceed 60%, and the method is unsuitable, since cypermethrin is degraded in methanol.
In this work, an extraction with an ultrasonic bath and reflux was used to extract permethrin and cypermethrin. Solvents for extraction were chosen, representing different classes of organic compounds in which they are highly soluble, namely hexane, butanol, ethyl acetate, acetone, carbon tetrachloride. Samples of cotton fabric containing 3 g / m² of the active substance with a solvent were placed in an ultrasonic bath for the same time. The results of the experiment are shown in figure 1.
Since none of the solvents gave results close to the nominal content of cypermethrin, a successive extraction was performed on an ultrasonic bath, first with acetone, to “wash” the pyrethroid binding substances, and then with hexane to remove it from the fabric. The required amount of the active substance was obtained only after 4-hour extraction. To reduce the total time of sample preparation, an attempt was made to extract cypermethrin by refluxing with ethyl acetate and carbon tetrachloride, the solvents that showed the best results in the extraction with an ultrasonic bath (figure 2).
The essence of the proposed method consists in extracting the active substance from the fabric by reflux a finely chopped sample with ethyl acetate for 3 hours. The extract is concentrated using a vacuum rotary evaporator, then filtered and quantitative determination of permethrin or cypermethrin by gas-liquid chromatography with flame ionization detection in the temperature programming mode is carried out. The sensitivity of the methods is 0.01 g / m² for permethrin and 0.15 g / m² for cypermethrin.
A method has been developed for the quantitative determination of cypermethrin and permethrin in tissues intended for the manufacture of protective clothing against ticks. The use of this technique in the development of new models of protective clothing will reduce the risk of its negative impact on consumers, while maintaining its effectiveness. The simplicity of the hardware design technique allows us to hope for its distribution throughout the territory of the Russian Federation.
A fully validated LC-MS/MS method has been applied to a small survey of pesticide residues in conventional and organic fruit and vegetable produce from markets in Turkey. The method employs the well-established QuEChERS clean-up followed by LC-MS/MS employing a database of 511 pesticide residues created from the analysis of pesticide standards. The mass spectrometer was operated switching between positive and negative ion modes as appropriate for each pesticide to achieve optimum sensitivity. Matrix-matched 6-point calibration was used throughout with recoveries from 88-112% spiked at 5 ng/g with an RSD of around 0.1%.Of 91 samples of conventional produce (potato, tomato, spinach, pepper, celery, apples, grapes, red pepper, lemon, fresh green banana, pomelo, raspberry, granadilla, red currants, rock melon, parsley, dill, mint, tomato, mushroom, fresh kale, California pepper, fresh basil, banana, nectarine, melon, Danjou pear, south Africa lemon and USA apple) multiple residues were detected above the LOD in twenty nine samples and 10 samples contained residues at levels exceeding the MRLs by more than ten-fold. Of 18 samples of organic produce, five samples contained low levels of multiple residues and one tomato sample contained pirimiphos methyl at five times the MRL. These results indicate a significant problem in misrepresentation of organic produce which has been treated with conventional pesticides.
Phthalates are multifunctional chemicals used in a variety of products such as soaps, shampoos, cosmetics, plastics, paints and pesticide formulations. Therefore, phthalates are present in our environment and human exposure can occur both via ingestion, inhalation, or dermal routes. Phthalic acid esters are non-persistent compounds that metabolize fast. The metabolic transformation of phtalates after the exposure starts with hydrolytic breakup of diesters. The hydrolytic monoesters that result from this molecular step are then excreted in the urine or are further processed as glucuronide conjugates, some of which are oxidized.
Determination of mono-benzyl-phthalate (MBzP) has been done using an electrochemical method. Three electrodes based on graphene (Gr), and graphene modified with iron(III)- phthalocyanine (Fe-Pc/Gr) or nickel(II) -phthalocyanine (Ni-Pc/Gr), were design. The sensors were used for the determination of mono-esters of phtalic acid in biological samples, e.g., human saliva and urine, using differential pulse voltammetry.
Under the optimum conditions, voltammetric response for all three electrodes were linear, with regression coefficients higher than 0.9980 and limits of detection (LOD) for the proposed sensors are very low, 1.387×10⁻¹¹ mol L⁻¹ (Ni-Pc/Gr), 2.338×10⁻¹³ mol L⁻¹ (Fe-Pc/Gr) and 1.848×10⁻⁸ mol L⁻¹ (Gr). The sensors were reliable used for the assay of mono-benzyl-phthalate in human saliva and urine.
The authors gratefully acknowledge the Romanian National Authority for Scientific Research, UEFISCDI for
financial support, under grant PN-III-P4-ID-PCE-2016-0050.
Rapid determination of antimicrobial susceptibility/resistance is the key factor to select an appropriate antimicrobial treatment and to eradicate infections promptly. Conventional antimicrobial susceptibility tests (ASTs) are not precise enough and very time consuming. In addition, resistant bacteria generally release an enzyme for converting the active antimicrobial to an inactive metabolite, which stirred us to develop a liquid chromatography-mass spectrometry (LC-MS/MS) method in our previous study for the rapid determination of resistance level as well as the selection of correct antimicrobial treatment.
In this study, we extended our previous exploration to determine the resistance of Staphylococcus aureus to penicillin G (PenG) in an animal-infection model by the LC-MS/MS rapid method. The method was successfully applied to rapid determination of resistance in S. aureus bacteremia (SAB) model.This newly developed method is able to determine the extent of antimicrobial resistance qualitatively and quantitatively within 1 h, and could be used to replace the conventional AST methods.
Due to the rapid aggression of environmental pollution across the world, the importance of establishing a robust pollution-monitoring plan cannot be overemphasized. Current analytical workflow for environmental pollution monitoring consists of a number of steps including sample collection from the field, addition of preservative, transportation to the laboratory, storing at controlled temperature, filtration, extraction of the target analytes using a sample preparation technique, elution of the analytes in organic solvent, solvent evaporation, sample reconstitution in a small volume of organic solvent and finally injecting an aliquot into the chromatographic system. This long list of steps involved in the sample preparation often incur substantial loss of the target analyte(s), and consequently,
result in underreporting of the true analyte concentration in the environmental water. A viable solution to minimize analytes loss is to develop a field deployable sample preparation device that would allow the entire sample preparation directly in the field.
Capsule phase microextraction (CPME) is developed to meet the 21 st century demands of sample preparation. CPME eliminates sample pretreatment/clean-up step from the sample preparation workflow. CPME utilizes a porous tubular polypropylene membrane capsule possessing 0.2 µm pore size and 1.8 mm internal diameter to encapsulate sol-gel organic-inorganic sorbent. The porous membrane capsule allows easy permeation of aqueous sample containing the target analyte(s) while protecting the sorbent from contamination by matrix interferents. A magnetic metal rod is embedded into the microextraction capsule that allows rotating the device when placed on a magnetic stirrer and diffuses the aqueous sample matrix for fast analyte-sorbent interaction and rapid extraction equilibrium.
High loading of sol-gel sorbent into the microextraction capsules providing excessive sample capacity for the target analyte(s), fast extraction kinetics due to sponge-like porous architecture of the sol-gel sorbent, protection of the sorbent from contamination via encapsulation into a porous tubular membrane capsule have made capsule phase microextraction (CPME) an impressive and robust sample preparation technique. After the extraction, a small volume of organic solvent is used to desorb the accumulated analyte(s). Due to high preconcentration factor achieved in CPME, no solvent evaporation and sample reconstitution is required. The prepared sample can be analyzed in gas chromatograph, liquid chromatograph or capillary electro chromatograph to obtain complimentary
information. The entire sample collection and preparation process can be carried out in the field without sacrificing the data quality. A large number of sorbents developed for CPME including nonpolar, medium polar, polar, cation exchanger, anion
exchanger, mixed mode and zwitterionic sorbents provides the separation scientists ample freedom to select appropriate sorbent chemistry for a given application. Ability to use the same microextraction capsule for more than 50 times makes the technique very cost effective. In the current talk, some fascinating data on environmental applications of CPME will be presented.
Mercury is a toxic metal emitted into the environment throught natural and anthropogenic sources. Dental amalgam, has been used over 200 in dental practice, it is composed about 50% of metallic mercury and 50% of metal powder composed of silver, copper, zinc and tin.
This study aims to evaluate the concentration of mercury in liquide effluents and quantify the amount of mercury content in dental amalgam waste generated by dental clinics of the city of El Khroub. The study reveals that there is a mercury contamination in dental wastewater collected. Mercury concentrations in wastewater were significantly high and exceeded the allowed concentration.
Bladder cancer is one of the most common urologic malignancies, which is more frequent in men than in women. The early diagnosis for this type of cancer still remains a challenge, therefore, some biomarkers such as p53, E-Cadherin, BTA and hyaluronic acid were taken into consideration for the detection of bladder cancer. p53 is a DNA-binding phosphoprotein that is coded by a tumor suppressor gene, TP53 and acts as a tumor suppressor . E-Cadherin plays a major role in malignant cell transformation, especially in tumour development and progression . BTA is bladder tumor antigen. Hyaluronic acid is an extracellular glycosaminoglycan metastasis promoter, which supports tumour cell adhesion and migration .
Stochastic mode was used for the measurements of these four biomarkers from real samples, because it provides a reliable qualitative and quantitative analysis and the molecules are identified according to their length, geometry, capacity of unfolding and speed of passing through a channel. In order to perform the analysis for early detection of bladder cancer, three sensors based on the modification of graphite paste with Chitosan l, Chitosan ll and Chitosan lll were designed and characterized. Results (characterization, and validation for whole blood samples and tumor tissues) obtained using these sensors will be discussed. Based on the results obtained for the characterization and the validation of the proposed stochastic sensors: high sensitivity and low limits of determination when used for the analysis of real samples, as well as on their capacity of performing of qualitative analysis of the proposed biomarkers, the stochastic sensors can be reliable used for screening tests of whole blood for bladder cancer, and the developed method has as feature the utilization for the screening of whole blood and tissue samples for early diagnosis of bladder cancer.
 D. Sartini, G. Muzzonigro, G. Milanese, V. Pozzi, A. Vici, S. Morganti, V. Rossi, R. Mazzucchelli, R. Montironi, M. Emanuelli. Cell Biochem Biophys. 2013, 65, 473–483.
 L. Cheng, D-D. Davison, J. Adams, A. Lopez-Beltran, L. Wang, R. Montironi, S. Zhang. Crit Rev Oncol Hematol. 2014, 89, 71-111.
 P-S. Nives. Cancer Cell Int. 2003, 3, 17-24.
The role of sensors in risk prevention and disaster in particular is well established today. In our work we focused on the case of air pollution in an industrial site at risk. It was to analyze and evaluate the capabilities of chemical sensors implanted in this site (complex GL1K Skikda) for monitoring air pollution. In the first part of our work, we have addressed the problem of air pollution by reviewing the various pollutants as well as technical gas analysis and chemical sensors. This allowed us the presentation of the complex GL1K Skikda (Algeria), in our study, with a detailed description of sensors operated. The last part of our work is dedicated to the results and discussions followed and targeted gas concentrations (methane, propane, butane) found in different sites (5P, 6P, GPL, 10) of the complex GL1K over time, and by exploiting two types of point sensors model GG SC4100, and linear barrier
IR5000 model IR5000. Following these results, we found the interest of calibration to show the real value of the concentration of explosive gases by point sensors with the measuring cell, and the kit. Given the complexity of issues related to the reliability of detection and location of point sensors and linear when the measured concentration is not stable. Thereafter, we tried to make improvements for the sole purpose of optimizing the detection system, we proposed solutions to allow the system to become more credible and better functional, and consequently better control the risk of explosion due to the target gas. Key words: Chemical gas sensors, air pollution, explosive gases.
One of the most serious environmental problems related to the mining industry in Algeria and the whole world, is the pollution from abandoned mine sites. Acid mine drainage (AMD) is a noteworthy source of surface water and sediment contamination. It contains a high sulphate content and dissolved metals such as; Pb, Cd, Fe, Zn, Ni, Cu, Mn, Cr, etc.To evaluate the level of contamination of surface water and sediments near the abandoned sidi kamber Zn/Pb mine, heavy metals concentrations (Pb, Cd, Fe, Zn, Ni, Cu, Mn) were determined in the samples of water and sediments of Guénitra dam and El-Souk River, who is a tributary of the dam located downstream of the abandoned mine. The Method of determination of heavy metals used the atomic absorption spectroscopy thermo scientific. The analyzes show a high degree of metals pollution in the waters of the El-Souk river and in sediments. Waters of the dam is less contaminated; however, the sediments of the dam are highly contaminated by lead. Therefore, the concentrations in the water far exceed the standards of potability (standard W.H.O., standard Algerien) whereas in sediments, the Pb contents exceed the content considered natural in sediments.
During last decades, some industrial processes (e.g., uranium, coal and phosphate mining, shale gas extraction) and nuclear accidents like Tchernobyl or Fukushima, have contributed to release radionuclides across the globe. Their persistence in the environment can contribute to ionizing radiations exposure risk to populations and ecosystems, and thus, environmental radiological monitoring is of great concern. Radium-226, alpha emitter whose progeny is the well-known radon gas, and Cesium-137, beta emitter, belong to the most radiotoxic radionuclides. Indeed, due to chemical properties respectively similar to those of calcium and potassium, they are able to replace them in biological processes, and can thus contribute to increase the internal dose. In order to assess the risk of chronic exposure, it is essential to have a deeper understanding of processes leading to radionuclides migration in the environment. However, their quantification in environmental samples (e.g., pore waters, root systems) presents many challenges: low sample volumes available (<10 mL), complex matrices and concentrations below instrumental detection limits. Their analysis requires the use of efficient sample pretreatment methods, combined to sensitive analytical methods. But existing sample pretreatment techniques fail to answer these criteria since they are multi-stage, time-consuming, often lack of selectivity and are not suitable for small sample volumes. This work aims to develop new sorbents showing high selectivity for these two radionuclides, in order to perform their determination with inductively coupled plasma mass spectrometry (ICP-MS), in small volumes of complex samples. In this context, synthesis of ion-imprinted polymers (IIPs) has for the first time been proposed in extraction and preconcentration processes of Ra and Cs.
Several IIPs have been synthesized using non radioactive elements as template ions: Cesium (Cs-133) and Barium, as an analog of Ra. Different syntheses have been achieved, modifying either the nature of reagents, solvents or proportions, in order to study their influence on selectivity. Non-imprinted polymers (NIPs) were synthesized and used in parallel to control the presence of specific cavities on IIPs. For this, polymers were packed in cartridges to characterize them by solid phase extraction (SPE), by comparing extraction recoveries between IIPs and NIPs. A first optimization of the washing step highlighted a good selectivity of IIPs for their template ions, with recoveries from 12 to 30% higher than NIP. This selectivity was further confirmed in presence of interfering ions from different chemical classes, under various chemical forms depending on the conditions of use (such as pH) of the IIPs: Mg, Sr, Mo, W, In, Tl, Pb, Bi, Nd, Th and U.
Food safety and environmental protection issues have attracted significant international attention in the recent years. The detection of organochlorine pesticides (OCPs) in food products is of key importance for the health of the consumers. Pesticides are found in food at very low concentrations, the separation and pre-concentration of the target analytes has become one of the most critical steps in the sample preparation technology. The QuEChERS is a type of sample preparation method for screening of pesticides in completely food matrixes. This procedure involves initial extraction with acetonitrile followed by a solid phase extraction with amine-loaded adsorbents in combination with hydrophobic C18 and graphitized carbon black for cleaning-up . In this work the application of magnetite nanoparticles modified with hydrophobic non-ionic surfactant Triton X-100 motives as an excellent clean-up agent is proposed. Hydrophobic groups grafted to the surface of magnetite nanoparticles can effectively remove non-polar components from the food matrix (fat, pigment, etc.) and then the particles can easily be separated from the extract by external magnetic field avoiding additional steps of centrifugation or filtration.
The sample preparation method based on QuEChERS implying the use of new magnetic nanocomposite has been applied for the monitoring of various OCPs in food products. Under the found optimal conditions such parameters as sensitivity, precision, recoveries have been evaluated for the target analytes by GC-MS method. The results have shown a good linearity (R2≥ 0.9916), satisfactory average recoveries reaching the values between 89 and 110%, RSD of 2-15 %, except those for the hexane extraction of strawberry, radish and watermelon samples. The OCPs have been detected in strawberry (α- HCH; lindane) and radish (α, β-HCH isomers) samples. The magnetic nanocomposites have provided the lower level of co-extracted interferences (including pigments) in the samples and have displayed a better clean-up performance than C18 or carbon adsorbents. Thus, the developed method demonstrates the improved puriﬁcation and simultaneous recovery of various OCPs.
. He Z, Wang L, Peng Y, Luo M, Wang W, Liu X., Food Chemistry 169 (2015) 372–380.
In this present study, the essential oils and volatile extract obtained from leaves of Myrtus communis L., growing spontaneously in Algeria, were extracted by conventional steam distillation (SD), and two Innovative processes: Instant Controlled Pressure Drop and ultrasound assisted extraction (UAE). The impact of extraction on yields, extraction time, chemical composition, antioxidant and antimicrobial activities were investigated.
The in vitro antioxidant activity of essential oils were determined by 2,2-diphenyl-1-picrylhydrazyl method and were compared to that found for the reference compound (BHT)
While the antimicrobial activity against several foodborne pathogens of each extract were examined in vitro assays by the minimal inhibitory concentrations (MIC) using a microdilution broth method.
For the three different extracts, the chemical composition was determined by GC-FID and GC / MS.
The yield of essential oil (EO) and time extraction obtained using SD, UAE and DIC methods were 0.43g EO/100 g dm for 240 min, 0.43g EO/100 g dm for 30 min and 0.56 g EO/100 g dm for 2 min respectively.
The most predominated compounds identified in DIC extract are α-pinene (23.33 %), eucalyptol (21.76%), eugenol (4.06%), methyleugenol (5.38 %), caryophyllene oxide (4.21%) and limonene( 2.20%). The main components identified in SD are α-pinene with 36.94%, followed by eucalyptol (19.08%), eugenol (3.73%), methyl eugenol (3.71%), α-terpineol (3.14%), and limonene (2.37%). For ultrasound assisted extraction, the chemical composition was dominated by α-pinene and eucalyptol with 36.05 and 19.10%, respectively. These compounds were escorted by eugenol (4.13%), methyl eugenol (4.02%), limonene (3.55%), geranyl acetate (3.18%), β-linalool (2.92%), and α-terpineol (2.33%).
All Eos reveal a moderate antioxidant activity. All extracts exhibit good antimicrobial activity against various pathological strains tested.
Analysis of the microstructure were also been undertaken on solid residue of myrtle leaves by Scanning Electronic Microscopy; they showed significant modifications of the cellular structure of DIC and AUE in comparison with conventional SD residual solid.
Keywords: Myrtus communis L., Essential Oils, Extraction, Steam Distillation, Ultrasound Assisted Extraction, Instant Controlled Pressure Drop (DIC), Antioxidant and Antimicrobial Activities
In this study we tested the ability of polyamide nanofiltration membrane to extract the ion of lanthanum (III). A three -level factorial design and response surface methodology was used to evaluate the effects of parameters: pH (3–9), pressure (6-13.5 bars), concentration (10-100ppm).
The results showed that the retention is quantitative (100%) for 10 ppm at pH = 6 with pressure equal to 6 bars.
The study confirmed the high lanthanum extraction using polyamide nanofiltration membrane.
|Extraction yield (%)|
|28,29,30||6||55||9.75||0||0||0||90.87, 97.23, 94.48|
|Feature||Symbole / Equation||Value|
Number of experimental
Number of tesys at (0,0,0)
Average yield at (0,0,0)
Square root of variance
Risk factor (chosen arbitrary)
Student test factor
Average error on the coefficient value(trust range)
Number of remaining coefficients
Model reponse at (0,0,0)
Discrepancy on average yield
Error on average yield discrepancy
Average yield for the twenty seven attempts
Degrees of freedom
Residual degrees of freedom
Observed Fisher test
S2 = Σ(Z0i-Z0)2 / ν
Δai = ±tν, α/2 S/N0.5
a0 (Z000 )
d= Z0-Z (0,0,0)= Z0-a0
Δd= ±tν,α/2 S (1/N+1/n)0.5 avec N = 27 & n = 3
Zm= Σ Zi /27
Sr2 = Σ (Zi-Zm)2 /(N-R)
Fobs, V1, V2
The volatile composition of seven honeys samples from various regions of Algeria and feeding on different plants have been determined. Headspace solid-phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) has been used for the chemical analysis of volatile and semi-volatile compounds in samples. All the experiments were made in saline medium (30% NaCl). In this work different parameters were studied such as extraction temperature (45°C and 55°C), fibre (PDMS and PDMS-CAR) and agitation. The results showed a great diversity in the chemical composition, in total hundred twenty for compounds of different chemical classes are identified, among them, compounds are found for the first time in honey. Analysis of the main components of PCA showed that Becharmonofloral honey for the plant Ziziphusspina-christi (H1) and Ain Dafla multi-floral honey (H5) have a specific composition compared to other samples.
This study demonstrated that honeys can be used as bio-indicators of air and soils pollution since HS-SPME-GC-MS allowed the detection of toxic compounds from some samples studied due to the use of agrochemicals and industrial wastes around.
In the aim of valuing Algerian flora, we focused in the study of Cistus Monspeliensis L. This shrub is distributed everywhere in Algeria, in tell, in the littoral and in forests. The objective of our work was mainly the identification of chemical compounds, the determination of the flavonoids and hydrolysable tannins contents in the alcoholic extracts and the estimation of the lethal dose 50 (LD50) of the aqueous extract.
The preliminary phytochemical tests performed on various extracts (aqueous, alcoholic and etherical) as well as on the plant’s powder showed the plant richness in secondary metabolites especially flavonoïds, gallic-tannins and leuco-anthocyanes.
The alcoholic extracts were analyzed for their flavonoids and hydrolysable tannins contents using the colorimetric assays. Quercetin and Tannic acid were used to estimate the calibration curve of flavonoids and hydrolysable tannins respectively. The result obtained was 0.21 milligram quercetin equivalent per gram of the dried plant for the flavonoids determination and 0.67 milligram tannic acid equivalent per gram of the dried plant for the hydrolysable tannins determination.
The median lethal dose is statistically the dose responsible for the death of 50% of the experimental animals. It is expressed as the weight of the test product relative to the body weight unit of the tested animals (mg / kg). The toxic effects observation of the product on the animals as well as the number of mortality is done every day during the 14 days of the experimentation. This pharmaco-toxicological examination has demonstrated the safety of the aqueous extract, hence the traditional use of the decoction.
Keys words: Cistus Monspeliensis L., chemical compounds, lethal dose 50.
This study concerns to the cloud point extraction of Blue Bemacid dye from an aqueous solution sulfate medium using di-(2-ethylhexyl) phosphoric acid (D2EHPA) ionic liquid as extractant in the presence of a nonionic surfactant (Triton X-100). A two-level factorial design and response surface methodology was used to evaluate the effects of parameters affecting extraction efficiency: pH (4.0–8.0), mass % of Triton X-100 (2%–10%), Na2SO4 (8%–10%) and blue Bemacid dye concentration (10–100 ppm).
Mathematical model has been developed to predict the effect of each variable and their interactions in the response (dye removal). A comparison between the predicted values using the model equation and the experimental values showed correlation coefficients higher thanR2> 0.998. The response of factorial design (dye removal) showed a high elimination of dye removal with a yield of elimination of 99%.
|Value of the actual variable||Value of the actual variable||Value of the actual variable|
|Triton X-100 (T)||X2||2||6||10|
|Initial dye concentration (D)||X4||10||55||100|
"This study aims to investigate uranyl (II) removal by the liquid-solid extraction technique using Lewatit TP 214 resin containing thiourea group in polystyrene-divinylbenzene matrix, in batch process. The optimal conditions for UO2(II) extraction were determined by studying the effects of parameters such as the contact time (0-180mn) with different weight of resin (0.015g, 0.03g, 0.1g), pH level (2-6) and the initial concentration of the UO2(II) ions (10⁻5-10-3M). The results showed remarkable affinity of resin towards uranyl (II) cations. The maximum uptake values of UO2(II) was 23.30 mg/g. Percentage removal increases with increasing initial pH solution, uranyl (II) cations removal was better in initial pH values of 6.0, at room temperature. The uptake kinetic for uranyl (II) onto Lewatit TP 214 was best described by the pseudo second order model."
|Weigt/Model||Lagergren (first order)||Pseudo second order|
This work is part of the development of local materials, such as vegetable fiber (palm fiber) and red clay from southern Algeria, widely used in the preparation of bricks as rural building materials. Vegetale fibers have very interesting properties, they are: renewable, biodegradable and low cost / lightness ratio. Their mechanical properties are very important. However, the predominant problem in this type of composite material is the weak adhesion of the matrix-fiber interface, probably attributed to the nature of the surface and the hydrophobic character of the natural fibers, thus leading to weak mechanical properties for the material. envisaged composite.
The purpose of this study is to treat palm fiber with a basic solution of sodium hydroxide (4% NaOH) for varying periods of time: 3, 7, 24 and 48 hours to improve interfacial adhesion.
The results obtained from the tests carried out on the composite reinforced with palm fibers treated during 7 hours, showed a clear increase as regards the resistance to bending and compression; it is respectively of the order of 57% and 60%, compared to the composite reinforced by the untreated fibers. It can be deduced that palm fibers can be considered as one of the suitable materials for clay reinforcement.
Waterborne nanocomposite polymer/clay formulations are of increasing interest [1.2] as a base for fabrication of hybrid materials  with tailored features of nanoscale dimensional characteristics . An interesting strategy toward the preparation of polymer/clay hybrid nanocomposite is the miniemulsion polymerization , because reducing the formation steps and inducing significant changes in properties of polymer nanocomposites occurred by incorporation a clay, as a stabiliser . The understanding of the mechanism ruling Pickering miniemulsion polymerization depends strongly on an accurate determination of the particle size and size distribution which are the most important miniemulsion parameters because they affect directly both the miniemulsion stability and the droplet nucleation. Dynamic light scattering (DLS) is a simple technique that makes possible the structural study of the miniemulsion independently of specific aspects sample preparation.
In this work, the DLS was exploited to investigate the inner structure of nanocomposite poly-acrylic/MMT droplets with modified Algerian montmorrilonite employed as stabilisater (before polymerization). The effet of several parameters such as MMT modification, quantity and intensity of shear on the size and distribution size, of poly-acrylic/MMTnanoparticles is discussed. The data analysis showed that the montmorrilonite play a crutial role in the formation of particle formation. Reducing amounts of MMT leads to smaller average particle sizes but inflicts longer nucleation periods, thereby broadening the particle size distributions.
- Biswas, M.; Ray, S. S. Adv. Polym. Sci. 2001, 155, 167–221.
- F.Bouanani Hybrid Latex Particles: Preparation with Miniemulsion Polymerization, MATEC Web 01035, 149, 2018
- Teixeira, R. F. A.; Bon, S. A. F. Adv. Polym. Sci. 2010, 233, 19–52.
- F. Bouanani, D. Bendedouch, J. Teixeira, L. Marx, P. Hemery, “Characterization of a miniemulsion by DLS and SANS”Colloids and Surfaces A: Physicochem. Eng. Aspects; 404,47– 51, 2012.
-Patel, M. J.; Gundabala, V. R.; Routh, A. F. Langmuir 2010, 26, 3962–3971.
The present work aims to reduce the impact of vat dyes by a natural and activated Algerian clay using the adsorption technique. The adsorption experiments show that the clay used is very effective in removing the vat dye at relatively low concentrations in an aqueous medium. The adsorption isotherms of the vat dye on the raw clay are satisfactorily described by the Langmuir model. Adsorption capacities in the range of 55.25 mg.g-1 for crude bentonite (BB), 55.20 mg.g-1 for sodium bentonite (BS), 51.78 mg.g-1 for red clay (AR) and 48.24 mg.g-1 for Madadid clay (AM) were determined from the Langmuir isotherm. These values show that the raw bentonite has a better adsorption capacity because it contains a large percentage of clay fraction.
Water pollution is a leading cause of death worldwide, and those forced to consume contaminated water suffer from debilitating diseases. Therefore, there is urgent need for developing eco-friendly, efficient and effective new generation advanced materials and methods for water treatment and for removal of micro pollutants . In this respect, Layered Double Hydroxides (LDHs) –clay minerals containing water and interchelated cations- have widely been used in water treatment  especially in removal of anionic species. Thiourea derivatives with conjugated oxygen or nitrogen donor sites represent some of the most important chelating ligands in coordination chemistry . However, to the best of our knowledge LDH's modified with 2-froyl thiourea modified LDHs have not reported yet. Therefore, in this study, ZnCr-LDH, ZnCr-DS-LDH, ZnCr- 2, Froyl Thiourea-LDH were synthesized ZnCr-LDH, ZnCr-DS-LDH, ZnCr- 2-Froyl Thiourea-LDH were synthesized according to the reaction scheme given below. Characterization was made via FT-IR, XRD and 13C-NMR techniques. Particle sizes and morphologies were examined via SEM/EDX and elemental analysis and thermal analysis were made by TG/DTG/DTA. Pore sizes and volumes were determined by BET analysis. Sorption studies were made by F-AAS. In the sorption studies for Cd (II) metal ion, parameters such as amount of sorbent material, pH, analyte concentration, eluent type and concentration, contact time and flow rate were investigated. Optimum values for sorbent amount, pH, contact time, analyte concentration, flow rate and eluent were found to be 0.4 g, 7, 25 minutes, 50ppm, 0.30 mL/min, 1 M EDTA, respectively. Sorption capacities for ZnCr-DS-LDH and ZnCr-Benzoyl Thiourea-LDH were found to be 43,02 mg.g-1 and 38,19 mg.g-1, respectively. This study revealed that both unmodified LDH's and those modified with 2-Froyl thiourea can be effectively used in Cd (II) removal as eco-friendly sorbent materials.
Desertification, population explosion, climate change brought along the challenge of access to fresh water at sufficient quality and quantity for vast majority of the world. However, conventional (waste) water treatment technologies and materials (active carbon, active sludge, nanofiltration, reverse osmosis membranes, etc.) are reported to be insufficient in their performance in cleaning waters contaminated in a complex and complicated way with pharmaceuticals, personal care products, surface active agents, Grease, various chemicals, etc. In order to overcome the problems related with quality and quantity nanotechnology was found to be effective . There is a need for developing advanced materials and methods for removing new generation micro pollutants . In this respect, Layered Double Hydroxides (LDHs) –clay minerals containing water and interchelated cations- have received much attention and have been used as eco-friendly, efficient and effective sorbent materials . However, to the best of our knowledge LDH's modified with benzoyl thiourea modifie LDHs have not reported yet. In this study, ZnCr-LDH, ZnCr-DS-LDH, ZnCr-Benzoyl Thiourea-LDH were synthesized. Characterization was made via FT-IR, XRD and 13C-NMR techniques. Particle sizes and morphologies were examined via SEM/EDX and elemental analysis and thermal analysis were made by TG/DTG/DTA. Pore sizes and volumes were determined by BET analysis. Sorption studies were made by F-AAS. In the sorption studies for Cd (II) metal ion, parameters such as amount of sorbent material, pH, analyte concentration, eluent type and concentration, contact time and flow rate were investigated. Optimum values for sorbent amount, pH, contact time, analyte concentration, flow rate and eluent were found to be 0.5 g, 6.3, 30 minutes, 50ppm, 0.25 mL/min, 1 M EDTA, respectively. Sorption capacities for ZnCr-DS-LDH and ZnCr-Benzoyl Thiourea-LDH were found to be 42,05 mg.g-1 and 38,19 mg.g-1, respectively. This study revealed that both unmodified LDH's and those modified with thiourea derivatives can be effectively used in Cd (II) removal as eco-friendly sorbent materials.
 Bottero, J.-Y., Rose, J., Wiesner, M.R., 2006. Nanotechnologies: tools for sustainability in a new wave of water treatment processes. Integrated environmental assessment and management. 2 (4), 391–5.
 Bolong, N., Ismail, A.F., Salim, M.R., Matsuura, T., 2009.Effects of emerging contaminants in wastewater and options for their removal. Desalination. 239 (1–3), 229–246.
 N. Ayawei, A. T. Ekubo, D. Wankasi, E.D. Dikio, 2015, Synthesis and Application of Layered Double Hydroxide for the removal of Copper in Wastewater. International Journal of Chemistry, 7(1), 122
In the current study, Phenanthroline (Phen) was found to be an efficient corrosion inhibitor for cast iron in one molar HCl solution .
Polarization curves, electrochemical impedance spectroscopy (EIS) and surface analysis, using scanning electron spectroscopy (SEM) and atomic force microscopy (AFM), were investigated to highlight the corrosion inhibition characteristics of Phen on cast iron in 1 M HCl.
Cathodic and anodic polarization curves revealed that Phen behaves as mixed type inhibitor and its inhibition efficiency, determined by EIS measurements, reached its maximum value of 96 per cent at 1.4 mM. The concentration increase improved the inhibition efficiency of Phen, and its adsorption on cast iron surface followed the Langmuir isotherm. The value of ΔG°ads and the effectiveness of Phen at high temperatures, suggest physico-chemical interactions of Phen on the cast iron surface .
Scanning electron microscopy (SEM) micrographs and atomic force microscopy (AFM) analysis confirmed the formation of a protective film on cast iron surface, resulting in the improvement of its corrosion resistance in the studied aggressive solution .
Keywords: Corrosion inhibition, Cast iron, Polarization curves,EIS, AFM, SEM
 B. Idir, F. Kellou-Kerkouche (2018) J Electrochem Sci technol 9(4):260-275.
 A. Ostovari, SM. Hoseinieh, M. Peikari, SR. Shadizadeh, SJ. Hashemi (2009) Corros Sci 51(9):1935–1949.
 L. Li, X. Zhang, J. Lei, J. He, S. Zhang, F. Pan (2012) Corros Sci 63:82–90.
INTRODUCTION: For several years, orthopedic prostheses for knee amputation have been studied and used to replace missing bone organs. It is well known that the success of a femoral implant is highly dependent on initial stability of the prosthesis and its osseointegration long term due to the optimal distribution of mechanical stress in the surrounding bone.
the chose of material and study of prorieties is first step than the new concepts of adding a buffer to prosthetic components of the implant system interposed between the prosthesis and the implant attenuates mechanical shock and minimizes mechanical stresses in the bone and the implant. The new design of the implant system was evaluated by three-dimensional finite element analysis techniques using Abacus program (6.12) to study the effect of damping material under physiological load on the equivalent von Misses stresses induced in the implant system.
In general, the proposed new system caused less stress in the femoral bone through the damping effect of effort and substantial impact by the barrier constraints (polymer) that we proposed.
New emerging contaminants suffering from low removal efficiency in traditional wastewater treatment process have attracted considerable attention, especial for pharmaceuticals and person care products (PPCPs). Non-Steroidal Anti-Inflammatory Drugs(NAISD) are widely used and prescribed as analgesic and antipyretic medicaments and was the prevalent species found in the effluent of wastewater treatment plant (Lin et al., 2010). Ibuprofen(IBU) is one kinds of Non-steroidal Anti-Inflammatory Drugs(NAISD) and become a new class of water pollutant (Gomez et al., 2007). IBU posses bioactive property and has a strong impact of the environment even in small concentrations (Miranda-García et al., 2011). Accordingly, the treatment of these wastewaters is important before discharging them into the ecosystem. The degradation of IBU by several oxidation processes has already been reported.
Recently, TiO2 occupies a remarkable place in the advanced oxidation technology, due to its high photocatalytic activity, excellent functionality, and cheap cost. However, the fast recombination of electrons and electron holes is detrimental to the photocatalytic activity of TiO2. It was reported that the smaller crystal size of photocatalyst would superiorly separate electrons from electron holes (Qu et al., 2013) Modifying TiO2 by incorporation of additional components, including metallic and non-metallic doping would diminish the energy gap of TiO2 and shift the adsorption edge to visible range (Senthilnathan and Philip, 2010).
The photocatalytic efficiency of Cobalt doped TiO2 catalyst (Co-TiO2) for degradation of IBU under UV–Vis light was evaluated in this study. Co-TiO2 was prepared by reflux method. The catalysts were examined by scanning electron microscope (SEM), X-ray diffractometry (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy, X-ray Fluorescence Spectroscopy (XRF), UV-Vis absorption spectroscopy, specific surface area, particle size and zeta potential measurements. Parameters affecting the degradation including photocatalyst amount, initial IBU concentration, pH, irradiation time, effect of organic and inorganic ions were investigated and optimized. The optimum amount of catalyst was determined to be 0.4%. Total Organic Carbon (TOC) analysis and chromatographically 98% IBU (20 mg/L) was degraded under UV-C light in 240 min, whereas 98% of IBU was degraded under visible light in 300 min.
Quantum calculations mainly based on density functional theory (DFT). with complete optimization of the geometry using the functional ones; BP86 and OPBE were carried out on platinum mononuclear complexes of general formula [Pt (μ1-L2) (CN-tBu) 2]: L = Cl, Br, Co (X) 4 [X: donor ligand 2 e]. The structures were studied with different spin states (singlet S = 0, triplet S = 1), and in different symmetries.
This analysis shows that electronic communication depends on the nature of the attached ligands.
Always presenting a tetracoordinated Pt (II) metal with a 16 EVM giving rise to materials have wide energy gaps HOMO-LUMO.
The Ziegler-Rauk energy decomposition analysis system was used to characterize geometry distortion, steric (electrostatic and Pauli) interaction, and orbital interaction terms in the total binding energy. The results showed that the interaction terms in all studied complexes are governed by a half covalent and double ionic characters, which are in agreement with the EELc (Electrostatic) and Eorb contributions (orbital), respectively, in the total interaction attractive (E ELc + Eorb).
Promoted tungstated zirconia (WZ) catalysts are active and selective for isomerization of light alkanes, offering good prospects for industrial application. This account is an abbreviated summary of what these catalysts are and how they work. La-promoted Tungstated zicronia (LWZ) was prepared by a slurry impregnation method. The textural properties as well as the acidities of the La-promoted catalysts were characterized by X-ray powder diffraction (XRD), N2 adsorption, NH3 temperature-programmed desorption (NH3 TPD) and Analyse thermogravimétrique (ATG). The catalytic behavior of LWZ for n-butane isomerization was studied in the presence of hydrogen at 300°C, WHSV=0.47h-1 and nC4/H2=6. In comparison to Tungstated zicronia (WZ), the catalytic activity of the La-promoted catalyst was improved.
Carbon black (CB) is a black pigment produced by thermal decomposition or partial combustion of natural gas, petroleum oil or coal oil. It is known with its high stability, electrical conductivity and heat resistance and used in many industries as pigment, adsorbent, reinforcing filler and catalyst . Also, in cosmetics it is used as dark pigment in eyeliner, mascara, lipstick and tattoo dyes . However, due to its production route and content of carcinogenic contaminants called polycyclic aromatic hydrocarbons (PAHs), its usage was controlled and limited by authorities . Therefore alternative solutions must be proposed in order to minimize the amount of carbon back used in cosmetic industry.
In this study, a green dispersant, sodium lignosulphonate (SLS) was used to increase the color intensity of CB when minimizing its amount of usage in cosmetic products. SLS is one of the most powerful and natural dispersant obtained by modification of lignin which is a natural polymer exist in the support tissues of vascular plants and some algae. pH effect and amount of SLS were investigated for optimization. Color intensity studies were performed using reflectance spectrometer. The results were correlated using Uv-Visible Spectrophotometer. As the target material is CB, all the absorbance measurements were made at the wavelength of maximum absorption that is 602 nm. The addition of SLS until a significant amount did not lead to a shift at the maximum absorption wavelength of CB. The studies with real cosmetic samples proved the positive influence of SLS on the color intensity of CB, providing health-safe cosmetic products by decreasing CB usage.
 W. Xu, H. Chen, H. Li, M. Wang, Colloids Surf.A. 2005, 266, 68–72.
 Federal Register Final Rule- 69 FR 44927 July 28, 2001: Listing of Color Additives Subject to Certification; D & C Black No.2. U.S. Food and Drug Administration. Available online. July 14, 2014.
 Regulation (EC) No 1223/2009 of the European Parliament and of the Council of 30 November 2009 on cosmetic products. Available online. July 14, 2014.
Reactive oxygen species (ROS) may damage biomacromolecules, such as DNA, lipids and cause several diseases. Endogenous and exogenous antioxidants can prevent or minimize this damage by eliminating ROS. Although ROS is produced in different ways, the most known way is the classical Fenton system containing Fe (II) and H2O2. This system has quite strong conditions and is the most well-known hydroxyl radical (•OH) production system. However, hydroxyl radicals are produced by the reaction of different metals in the low oxidation stage with hydrogen peroxide.
Although cobalt is one of the metals leading Fenton reaction, Co(II)- H2O2 Fenton system has milder conditions for ROS generation. Here, ROS was produced with both Fe(II)-H2O2 system  and Co (II)-H2O2 system  and in both cases the protective effects of some selected antioxidants were examined. Synthetic DNA was used a biologically relevant probe for detecting ROS induced damage and Fenton-induced DNA damage could perfectly measure by colorimetric “CUPric ion Reducing Antioxidant Capacity” (CUPRAC) assay.
In this assay, the oxidized species derived from DNA were CUPRAC-reactive while intact DNA was not. In the presence of antioxidants (AOx), since ROS are scavenged by antioxidants, the damage occurred on DNA decreases. Therefore, a reduce is observed in CUPRAC absorbance. In the presented study oxidative hazard was accomplished in different pH values obtained by different buffers. While NH3/NH4Cl buffer (pH 9) was used for Co(II)/H2O2 system, NaH2PO4/Na2HPO4 mixture (pH 7) was used for Fe(II)/H2O2. Both reactions were accomplished at 37°C, and Fenton reactions were stopped with trichloroacetic acid (TCA). A suitable aliquot of this was added to CUPRAC reaction mixture (Cu(II)-Neocuproine complex at pH 7), and the absorbance was recorded at 450 nm.
Ethanol is very common solvent to dissolve AOx compounds nevertheless in Fe(II)-H2O2 system CUPRAC active products generated from ethanol. It’s interpreted as a consequence of harsh Fenton conditions came from classical Fenton system (Fe(II)- H2O2). Therefore, a milder Fenton system was tested, the problem is solved by using Co (II) instead of Fe(II). It is also known that the oxidative conditions in human body is much more moderate. In this point of view using this system provides more realistic conditions for modelling human body. Fenton induced DNA damage systems were used to test both oxidative stress and antioxidant defense.
The tested AOx compounds could be sorted in decreasing order of their slopes as: GA>AA>NAC>CYS>GSH>HCYS for Fe(II)- H2O2 Fenton system, and GA> CAT >CFA> EC for Co (II)-H2O2 Fenton system. This order was in accordance with established structure activity relationships. The methods were also applied to various real samples.
 S. Uzunboy, S. D. Çekiç, E. Eksin, A. Erdem, R. Apak2017, Analytical Biochemistry, 518, 69-77.
 S. Uzunboy, S. D. Çekiç, R. Apak, 2019, Analytical Letters, in press
To assess the effect of the matrix composition on the intensity of X-ray radiation in X-ray spectral electron probe microanalysis (EPMA), the simulation of electron trajectories in matter by the Monte Carlo method was spread. Among the early works, the model of Love, Cox and Scott  should be noted, which is quasi-one-dimensional, that is, it takes into account only one spatial coordinate z and the depth of the sample. In  this model was supplemented and two spatial coordinates were taken into account. Despite the fact that the two-dimensional model is approximate, it allowed to qualitatively describe the dependence of the intensity of the analytical signal on the size of the inclusions of native gold in a homogeneous sulfide matrix. Later comparable results were obtained in three-dimensional modeling . However, it remains unclear whether the use of a two-dimensional model to describe the distribution of X-ray radiation in a sample is correct.
The geometry of X-ray excitation at EPMA has axial (cylindrical) symmetry. From this point of view, two coordinates are enough to describe the processes of interaction of electrons with matter. The results of modeling using the author's program "Heron" show that to calculate the absorption corrections it is enough to use a two-dimensional Monte Carlo model. The figure shows the distribution functions of x-ray radiation in the depth of the sample φ(ρz) for Au La, built on the results of 2D and 3D modeling. In spite of the fact that the peak displacement is observed in 2D model calculations, the results of integration of the function φ(ρz) do not differ significantly in 2D and 3D calculations. Thus, the 2D model can be used to assess the effect of matrix effects in EPMA.
The reported study was funded by RFBR according to the research projects No. 18-33-00369, No. 17-05-00095, No. 18-33-20104.
1. Love G., Cox M.G.C., Scott V.D. Journal of Physics D: Applied Physics, Vol. 10, No. 1, 1977.
2. Tatarinov V.V., Finkelshtein A.L., Kravtsova R.G., Pavlova L.A. Analytics and control, Vol. 21, Issue 4, 2017.
3. Finkelshtein A.L., Tatarinov V.V., Finkelstein E.A., Pavlova L.A., Kravtsova R.G. X-Ray Spectrometry, Vol. 47, Issue 6, 2018.
It is well established that deficiency or the exposure of various elements has several effects on human health. Iron is an essential element for almost all living organisms because it participates in a variety of metabolic processes. Iron has the capacity to accept and donate electrons readily and this capability makes it essential for the human body . However, because iron has the ability to form free radicals, its concentration in body tissues must be very regulated because in excessive amounts, it can lead to tissue damage. It can damage tissues by catalyzing the conversion of hydrogen peroxide to free-radical ions which attack cellular membranes, protein and DNA. Iron metabolism disorders are among the most common diseases of humans . In this study we Investigated the reaction of different iron compounds using N,N-Dimethyl-p-phenylenediamine dihydrochloride (DMPD) reagent. Normally when DMPD is in the presence of a suitable oxidant solution, a colored radical cation is formed DMPD•+. When DMPD•+ is consumed by antioxidant compounds cause a discoloration of the solution. Mehdi et al. added DMPD on human plasma samples to measure oxidative conditions and the results showed that during human aging the plasma oxidative capacity increases significantly . We modified this study to apply it on inorganic Fe(II), Fe(III) salts and biological iron compounds. When Fe (II) and Hemoglobin-DMPD did not give results with Fe (II), hydrogen peroxide was added and Fe (II) and hemoglobin were evaluated. In our assay a solution of DMPD at an acidic pH and in the presence of a suitable oxidant solution, can form a stable DMPD•+ which shows a maximum of absorbance at 550 nm. The optimized method was applied to different inorganic iron salts FeCl3.6H2O, FeC6H5O7.H2O, FePO4.2H2O, Fe(NH4)2(SO4)2.2H2O, Fe(NO3)3.9H2O, FeSO4.7H2O, FeCl2.4H2O, FeNH4 (SO4)2.12H2O. Then the method was applied on biological iron compounds such as ferritin, hemoglobin, myoglobin, cytochrome c, lactoferrin, transferrine and fetal bovine serum. Finally, it was applied on several commercial iron containing drugs such as, ferro sanol, maltofer, ferrum fort. The experimental protocol is rapid and inexpensive, ensures sensitivity and reproducibility in the measure of different inorganic iron salts, biological and commercial ferrous containing compounds.
 C.P. Gupta, (IOSR-JAC) Volume 7, Issue 11 Ver. II. (Nov. 2014), PP 38-46.
 J.M. McCord, Journal of Nutrition (Nov. 2014), 134(11):3171S-3172S
 M. M. Mehdi, S. I. Rizvi, Analytical Biochemistry, 2013, 436, pp. 165–167.
Keywords: DMPD, iron, biological iron compounds
The frequent burning of Arabian incenses namely, ‘Bakhour’ is on the rise over the years following the traditional practices especially, by the residents of Arab countries. Studies indicated inconsistent results of hazardous mercury (Hg) concentrations in such incenses due to the restricted detection limits (0.1ppb) met with spectroscopic instrumentation. A direct mercury analyzer (DMA-80, Milestone, Italy) used in this study solved this constraint which measured Hg with the least detection limits of 0.0015ng/g onward. Common brands of incenses (16 types) from the six Kuwait Governorates local markets and collected at random showed consistent, precise and reproducible results with DMA-80. The high Hg concentrations in perfume-sprayed incenses were in converse to the Hg concentrations in the non-perfume-sprayed incenses. This showed that the Hg contaminant in the incenses was dependent on the added composition and concentrations of the perfumes. Moreover, the Hg concentrations in both the classified incenses indicated significant Governorate-wise variations. This attributes to the (a) native’s selectivity of ‘Bakhour’, (b) regional specificity of residents in their cultural activities, (c) profuse and recurrent uses and, (d) population proportionality. Furthermore, this study suggests that inhalation of perfumed incenses and their smoke may cause deleterious respiratory ailments in synergism with the indoor and outdoor air quality despite the positive therapeutic effect of such incenses recently, described.
Water shortage is recognized as one of the key issues facing many countries. However, the water demand is still increasing due to population growth and higher standard of living. A several water resources are available in Algeria. Unfortunately majority of these ressources are not quantified. The physicochemical analysis of water ressources can play a very important role in future water management and prospective sustainable living in Algeria.
In this work, special attention is given to the source waters of the Bouira region.
The objective of this work is to contribute of water quantification from recovered sources at different sites of Bouira. Bouira is located north of Algeria. The characterization of these sources allowed us to evaluate quantitatively and qualitatively the quality of waters in the region of Bouira. Hydrochemical and staistical method were used for chemical analysis
The analysis of the samples have concerned the physical and chemical parameters such as pH, temperature, conductivity and ions of Ca2+, Mg2+, Na+, K+, SO42-, NO3-, NO2-, HCO3-, Cl- and PO43-.
The use of the Piper and Stabler diagram, the correlation matrix and the statistical analysis of the data by the PCA made it possible to carry out a hydrochemical study of these source waters and to know their chemical facies and to classify them. Statistical analysis of the data allowed us to note that a significant correlation existed between certain parameters and also to identify the distribution of the mineralization of these waters.
The various analyzes carried out on samples of water from the Bouira region have revealed the behavior of some parameters describing the physicochemical water quality.
Descriptive analysis of physical and chemical parameters showed that the main elements measured in groundwater in this region for the different sampling stations indicate a difference in concentration between the different measuring stations.
Analyses are performed by UV-Visible spectrophotometry, flame spectrophotometry and atomic absorption.
Antibiotics are found very often in water, especially around the chicken farms. Therefore, fast screening tests of water for antibiotics is a high need for preventing unwanted treatment of population with antibiotics. Two stochastic sensors based on the immobilization of a complex of protoporphyrin with zinc in two different carbon matrices: nanodiamond paste and nanocarbon paste were design, characterized and validated for the assay of amoxicillin, ampicillin, and biotin in water samples. The very low limits of determination obtained using these sensors facilitated the assay of these antibiotics in very low quantities in water samples (as low as fg/mL); this is an excellent advantage versus other methods, e.g., chromatography. The results obtained for the simultaneous assay of these antibiotics in water will be shown.
The authors gratefully acknowledge the Romanian National Authority for Scientific Research, UEFISCDI for financial support, under grants, PN-III-P4-ID-PCE-2016-0050.
In present study a new Schiff’s base polymer (SBP) has been synthesized by condensation of synthesized amino-polystyrene copolymer resin with Triflouroacetylacetone (TFAA). After characterization of synthesized polymer removal of 2-chlorophenol (2-CP), 2, 4-dichlorophenol (2, 4-DCP) along with phenol was optimized using Response Surface Methodology (RSM). Eighteen runs design were performed in order estimate effect of variables such as solution pH, concentration of adsorbate, agitation time and amount of polymeric resin and their interaction effect on removal. A good agreement between experimental and predicted removal was obtained using Draper-Lin composite design. Maximum % removal obtained were 87.83%, 95.86% and 99.92% for phenol 2-CP and 2, 4-DCP respectively with more than 99% agreement between R2 and R2adj. Time has found to have significant positive effect on percentage removal of all three analytes, whereas, pH was shown to have significantly inverse effect. Interaction term time and concentration have significantly inverse effect on removal of phenol and 2-CP, whereas the same term had no significant effect on removal of 2, 4-DCP.
Equilibrium adsorption and kinetic studies for all three analytes were also carried out. Recovery of adsorbed phenol, 2-CP and 2, 4-DCP were checked by different solvents and was found to be quantitative (~99%) with methanol. The model was validated by performing sorption experiments at optimum conditions
The present contribution reports on the development of a paper-based analytical device (PAD) that enables the non-instrumental quantitative determination of target analytes through formation of suitable volatile analytes that selectively react with a recognizing element present in the detection area of the cellulose substrate. Formation of hydrophobic barriers was required to physically separate the detection area from the injection zone of the cellulose substrate, thus allowing the use of chemically incompatible recognizing elements (confined in the detection area) and derivatisation agents (injected through the injection zone) in the same procedure. The applicability of the proposed PAD was evaluated for determination of arsenic speciation in waters. The proposed method involved in situ AsH3 generation under selective conditions for As(III) and total As determination and exposure of a PAD containing Ag(I) in its detection area to the headspace above the sample. The colored product formed in the PAD when exposed to arsine enabled the quantification of As species after digitization and image processing. Experimental parameters were evaluated, including color mode detection, type of cellulose substrate, amount of recognition element, AsH3 generation conditions (concentrations of sodium borohydride, citric acid and hydrochloric acid) and sampling time. Under optimal conditions, the method showed limits of detection and quantification of 1.1 and 3.6 ng/mL, respectively, and the repeatability, expressed as relative standard deviation, was 7.1% (n=8). The method was successfully applied to the determination of As(III) and total As in water samples, with recoveries in the range 88-112%, and validated against a European Reference Material (ERM®-CA615 groundwater). Characterization of PADs in the absence and presence of AsH3 was finally performed by means of scanning electron microscopy with energy-dispersive X-ray spectrometry, unveiling the formation of nanoparticles and larger size particles distributed along the cellulose microfibrils.
Financial support from the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-68146-P) (MINECO/FEDER) is gratefully acknowledged. F. Pena-Pereira thanks Xunta de Galicia and University of Vigo for financial support. The CACTI facilities (University of Vigo) are also acknowledged.
 J. Ma, M.K. Sengupta, D. Yuan, P.K. Dasgupta, Speciation and detection of arsenic in aqueous samples: a review of recent progress in non-atomic spectrometric methods, Anal. Chim. Acta 831 (2014) 1-23.
 A.W. Martinez, S.T. Phillips, M.J. Butte, G.M. Whitesides, Patterned paper as a platform for inexpensive, low-volume, portable bioassays, Angew. Chem. Int. Ed. 46 (2007) 1318-1320.
 F. Pena-Pereira, L. Villar-Blanco, I. Lavilla, C. Bendicho, Test for arsenic speciation in waters based on a paper-based analytical device with scanometric detection, Anal. Chim. Acta 1011 (2018) 1-10.
 C. Bendicho, F. Pena-Pereira, L. Villar-Blanco, I. Lavilla, Dispositivo y método colorimétrico no instrumental para especies químicas volátiles, ES 2 679 643 A1.
It is known how atmospheric pollution is due to the contribution of different individual pollutants which their importance are related to certain climatic factor. With the aim of getting representative estimates of atmospheric pollution, the formulation of the Rasch model can be an appropriate technique. Thus, after applying the Rasch method at some urban and rural location in Extremadura (Badajoz, Cáceres and Monfrague), a ranking of all days according to their level of atmospheric pollution and the influence of each individual pollutant, and climate factor on the environmental deterioration was obtained.
Ozone and some climatic factors are the most influential items on atmospheric pollution. Particularly, air temperature and solar radiation, which are related to the ozone generation, are the most important.
The authors thank to Junta de Extremadura (Research Group TIC008, Research Group FQM003 and Research Group 10045DTERMA) and Ministerio de Economía y Competitividad of Spain (Project CTQ2014-52309P), both co-financed by European FEDER funds, for partially financing this work.
Contamination of water with pesticides is a major problem for human health. Indeed, traces of pesticides have been detected in humans and breast milk.
Metribuzin is an herbicide of the triazine family classified by WHO at moderate risk to humans. The herbicide is increasingly used by the Algerian farmer in vegetable crops. Water contaminated with this herbicide was treated by electrocoagulation. Electrocoagulation is an interesting process; It has several advantages. It requires simple equipment, it avoids the use of chemicals that are themselves a source of pollution and can be used in rural areas where electricity can be replaced by electricity solar energy (Mameri and al., 1998).
The reduction of metribuzin obtained using an electrochemical reactor with concentric cylindrical bipolar iron electrodes was satisfactory. Optimized operating conditions were determined at Co = 200 mg / L,i = 18Am-², S = 0.5 g / L, pH = 6 and D = 62 cm³/s. Under these conditions, the rate of elimination of the pesticide was 89%. Coupling this electrochemical process with the advanced ultraviolet oxidation process was even more effective, increasing the overall 95% pesticide removal rate.
Emerging contaminant refers to any chemical discovered in the environment that is not persistent; however, the presence of such chemicals is permanent due to continuous introduction from diverse uncontrolled sources. They consist of many compounds of anthropogenic and natural origin, including personal-care and industrial products, pharmaceuticals, pesticides, hormones, industrial chemicals, among others. Some of them (v.e. bisphenol A, triclosan, 17α-ethinylestradiol and 17β-estradiol) are classified also as endocrine-disrupting chemicals because they have the potential to modify normal endocrine system functions .
The main limitation in the analysis of these contaminants is not only the concentration range in which they are found (ng L-1 to μg L-1), but also the wide range of their physical-chemical properties. Therefore, for a simultaneous determination of them, methodologies with high-quality and versatility analytical are necessary. Rotating-disk sorptive extraction (RDSE) is an alternative microextraction technique with the following premises: the use of low sample volumes, a configuration of the device allowing the incorporation of laminar and powder phases with different polarities (high versatility), and the lack of device deterioration during the extraction, since the extracting phase is not in contact with the extraction container [2,3]. Previously described methodologies for these analytes have focused only on specific analysis for limited chemical families of contaminants. The aim of this research was to develop a simultaneous method for the determination of nonsteroidal anti-inflammatory drugs, parabens, natural and synthetic hormones, bisphenol A and triclosan in water samples. Finally, the method was applied for the analysis of natural and wastewater samples of a wastewater treatment plant.
Prior to GC-MS analysis, the derivatization conditions were optimized. The optimum values were: 70 µL of N-methyl-N-(trimethylsilyl) trifluoroacetamide, 80ºC and 35 min. The chromatographic run was developed in 25 min for the total compounds. Different sorbents phases and extraction times were studied, the extraction was implemented using Oasis® HLB and 60 min, respectively. In well and river waters, it was possible to quantify ethyl paraben and acetylsalicylic acid, in the effluent and influent of wastewater samples, the same analytes were detected, but in higher concentration. In addition, triclosan and naproxen were quantified in both kinds of waters, and ibuprofen was quantified in influent wastewater.
This analytical strategy proposes improvements in terms of derivatization, chromatographic analysis time, extraction times and analytical quality with respect to others already reported.
The authors would like to thank FONDECYT (Regular Project 1180742) and CONICYT (National PhD scholarship 21180429 and PAI Project PAI79170018) for financial support.
 S. Sauvé, M. Desrosiers, Chem. Cent. J. 8 (2014) 1–7.
 M. Becerra-Herrera, V. Miranda, D. Arismendi, P. Richter, Talanta 176 (2018) 551–557.
 Y. Corrotea, N. Aguilera, L. Honda, P. Richter, Anal. Lett. 49 (2016) 1344–1358.
Nowadays, the concern about the occurrence of traces of emerging contaminants in the environment has increased . These contaminants have impacts on the human health and the aquatic ecosystems, affecting both target and non-target organisms. Even though the presence of these compounds in water and soil samples has been revealed in several analytical studies worldwide, few reports described the occurrence and bioaccumulation of emerging pollutants in Argentina.
During the chromatographic analysis of complex samples, several unknown substances that coelute are usually present. In these cases, selectivity may be mathematically restored by applying multivariate data analysis. In particular, the multivariate curve resolution-alternating least squares (MCR-ALS) algorithm is useful to model multiway analytical data of complex systems that, in addition, do not fulfill a trilinear model .
In the present work, the occurrence and associated ecological risk of fluoroquinolones were investigated in rivers and farm wastewaters of San Luis, Santa Fe, Córdoba, Entre Ríos and Buenos Aires provinces of Argentina by high-performance liquid chromatography (HPLC) coupled to fast-scanning fluorescence detection (FSFD), and data modeling by MCR-ALS, and ultra-high performance liquid chromatography (UHPLC) coupled to triple quadrupole mass spectrometry detection. The maximum concentrations of ciprofloxacin, enrofloxacin, ofloxacin, enoxacin and difloxacin in wastewater were 7.7, 11.9, 1.78, 22.1 and 14.2 μg L–1, respectively. In the case of river samples, only enrofloxacin was found at a concentration of 0.97 μg L–1. The individual risk to aquatic organisms associated with the water pollution due to fluoroquinolones was higher than 1 for some species. The proportion of samples classified as high risk was 87.5% for ofloxacin, 63.5% for enrofloxacin, 57.1% for ciprofloxacin and 25% for enoxacin. Secondly, the bioaccumulation and ecotoxicological effects of four antiretrovirals (lamivudine, stavudine, zidovudine and nevirapine) in tadpoles after 48h of exposure in aqueous solutions were studied. The analytical procedure involved a simple extraction method followed by UHPLC coupled to diode array detection (DAD) and MCR-ALS analysis for data processing. Under the studied conditions, the investigated analytes, in special nevirapine, showed possible bioaccumulation in tadpoles. In addition, the enzymatic biomarkers measured to evaluate the ecotoxicological effects displayed acethylcholinesterase activity similar to the control group, while the glutathione S-transferase activity was increased.
In conclusion, the use of chemometric algorithms allows the prevalence evaluation of fluoroquinolones in water and the determination of antiretrovirals in tadpoles, providing information about concentration levels that could be potentially risky for the aquatic ecosystem, and harmful to biodiversity.
 P. Bottoni, S. Caroli, A.B. Caracciolo, Toxicol. Environ. Chem., 92 (2010) 549-565.
 G.M. Escandar, A.C. Olivieri, N.M. Faber, H.C. Goicoechea, A. Muñoz de la Peña, R.J. Poppi, TrAC, Trends Anal. Chem., 26 (2007) 752-765.
The study of the inorganic fraction of peat sediments allows to estimate changes in the natural environment, both on regional and global scales. The dividing of core into small parts improves the time resolution of climate records, however, it significantly limits the mass of the studied material. The absence of reference materials of peats with certified contents of rock-forming elements, as well as high content of the organic matter complicate analysis. The X-ray fluorescence (XRF) analysis is widely used for the quantitative determination of rock-forming elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe) in low-mass samples, however, it was practically not used for peat analysis .
In this work, two sample preparation techniques were compared: the homogenization of calcined samples (110 mg) by fusing with lithium metaborate  and pressing the powder samples (300 mg). The measurements were performed on wavelength-dispersive X-ray fluorescence spectrometer S8 Tiger (Bruker AXS, Germany). Theoretical and experimental assessments of the mineralogical effect and particle size distribution on the XRF intensity showed that sample preparation makes the main contribution to the error of analysis. Calibration curves were constructed using certified reference materials of continental sediments, river and sea silts and clays. The accuracy of the XRF analysis of peat sediments was assessed by comparison with the results obtained by atomic emission flame photometry, spectrophotometry and atomic absorption spectrometry. The relative deviation of the XRF and reference techniques results is higher for peat samples with high organic matter contents. The accuracy of the XRF analysis is higher for the analysis of samples homogenized by fusion, and both sample preparation techniques satisfactory accuracy of quantitative analysis according Z-criteria. Results of XRF and palynological analyses allow to understand the key indicators of the natural variability of climate and the natural environment and to obtain data for regional paleoecological reconstructions.
The work was performed using the equipment of the «Isotope-Geochemical Research» and «Geodynamics and Geochronology» Joint Use Centers of the Siberian Branch of the Russian Academy of Sciences with the financial support of the Ministry of Education and Science of the Russian Federation (project 0350-2016-0026), Russian Science Foundation (project 17-77-10118) and the Russian Foundation for Basic Research (project 19-05-00328).
 Amosova A.A., Chubarov V.M., Pashkova G.V., Finkelshtein A.L., Bezrukova E.V. Wavelength dispersive X-ray fluorescence determination of major oxides in bottom and peat sediments for paleoclimatic studies // Applied Radiation and Isotopes. 2019. V. 144. P. 118-123.
 Amosova A.A., Panteeva S.V., Chubarov V.M., Finkelshtein A.L. Determination of major elements by wavelength-dispersive X-ray fluorescence spectrometry and trace elements by inductively coupled plasma mass spectrometry in igneous rocks from the same fused sample (110 mg) // Spectrochimica Acta. Part B: Atomic Spectroscopy. 2016. V. 122. P. 62-68.
 Thompson M., Webb P.C., Potts P.J. The GeoPT proficiency testing scheme for laboratories routinely analysing silicate rocks: A review of the operating protocol and proposals for its modification. Geostandards and Geoanalytical Research. 2015. V. 39. P. 433-442.
Determination of the ore elements (Fe, Mn, Co, Ni, Cu, Zn) contents is the necessary stage of the deep-water ferromanganese deposits development. The X-ray fluorescence (XRF) analysis is widely used for the analysis of geological objects. Unlike continental ores, there are not so much certified reference materials of ferromanganese nodules were developed . Their mineralogical and elemental composition varies considerably depending on the sampling site. Therefore comparing of different sample preparation techniques taking into account matrix effects for XRF analysis of ferromanganese nodules seems actual.
To construct the calibration curves, certified reference materials of ferromanganese nodules and crusts were used. Ferromanganese nodules have porous structure and even after drying are able to accumulate moisture from the air. Therefore certified reference materials were dried for 24 hours at 105 °C, then a pellet was pressed from a part of the dried powder, another part was calcined at 950 ° C for 4 hours in a muffle furnace, the mixture of 0.25 g of calcined sample with 7.5 g of lithium tetraborate was homogenized by fusion . It was shown that it is necessary to take into account the spectral overlaps of the MnKβ1,3 line tail on the FeKα1,2 line, the FeKβ1.3 line tail on the CoKα1,2 line, and the NiKβ1.3 line tail on the CuKα1,2 line. The overlaps of the CuKβ1,3 line tail on the ZnKα1,2 line and the CoKβ1.3 line tail on the NiKα1,2 line are insignificant. We compared the matrix effects correction using the fundamental parameters method and empirical intensities. Analysis of the ferromanganese nodules by atomic absorption spectrometry showed that for determination of Fe and Mn, empirical correction allows to achieve the best accuracy for both sample preparation techniques. For Co, Ni, Cu and Zn determination it is optimal to choose a theoretical correction when analyzing compressed tablets. For the analysis of fused samples both theoretical and empirical correction of matrix effects can be used. Obtained data were compared according Z-criteria  and were accepted as satisfactory.
The work was performed using the equipment of the «Isotope-Geochemical Research» and «Geodynamics and Geochronology» Joint Use Centers of the Siberian Branch of the Russian Academy of Sciences with the financial support of the Russian Foundation for Basic Research (project 18-33-20103).
 Wang Y., Song H., Wang X. Ocean Manganese Nodule and Sediment Reference Materials // Marine Georesources and Geotechnology. 1998. V. 16. P. 321-334.
 Amosova A.A., Chubarov V.M., Panteeva S.V., Finkelshtein A.L. Determination of major elements by wavelength-dispersive X-ray fluorescence spectrometry and trace elements by inductively coupled plasma mass spectrometry in igneous rocks from the same fused sample (110 mg) // Spectrochimica Acta. Part B: Atomic Spectroscopy. V. 122. P. 62-68.
 Thompson M., Webb P.C., Potts P.J. The GeoPT proficiency testing scheme for laboratories routinely analysing silicate rocks: A review of the operating protocol and proposals for its modification // Geostandards and Geoanalytical Research. 2015. V. 39. P. 433-442.
Polymer inclusion membranes (PIM) used for selective transport and separation of metal- lic ions has emerged in recent times. Their expansion depends on the method of preparation and their structure. This paper reports on the synthesis of a novel class of polymer inclusion membranes based on two polymers cellulose among which triacetate (CTA) plasticized by 2-Nitrophenyl pentyl-ether (NPPE) and doped with crown ethers incorporated into the poly- mer as a metal ion carrier. All the membranes were characterized by several techniques as well as Fourier Transform Infra - Red (FTIR), X-ray Diffraction (XRD), and Thermogravi- metric Analysis (TGA). As application, transport of Pb(II) and Cd(II) ions in polymeric membranes (PIM) was studied. Overall, our results showed that the addition of plasticizer with two polymers resulted in homogeneous and hydrophobic membranes whose physical properties, such as density, thickness, and hydrophobicity, were modified. All membranes were thermally stable up to nearly 200 C. The study of the transport across a polymer inclusion membrane has shown that the lead or cadmium transport efficiency was increased using NPPE as carrier.
As a premiere for Romanian cultural heritage, it been made a complex investigation over the monument degradation causes and was asset a correlation between monitored climatic factors and results obtained by different analytical techniques (ICP-MS and ATR-FTIR). This research is a first step of an ambitious project, based on a complex acquisition of microclimatic data during a long-term monitoring (i.e. on three complete seasons). The investigations and obtained results are representative for old historical monuments of Romania, rehabilitated without preliminary scientific studies on building materials and climatic changes.
With respect to the analysis carried out on the risks for the conservation and rehabilitation of historical monument the mainly microclimatic parameter, a real danger for the conservation of the material structure, is humidity, due to its significant and repeated variations during a complet season. Throughout monitoring periods, values of temperature and humidity exceeded the values for the same periods of last year. In this respect, climatic effects due to seasonal changes are the reason for temperature variation and humidity high values which also increasing the chances of fungus and perennial plant occurrence. The degradation phenomena including soiling, are currently taking place not only to the surface of original material from inside of the monument, but on metallic materials as well (structure of reconstruction), which are affected by corrosion phenomena. The monitoring data collected is the main source of information for carrying out a risk analysis, and for the future achievement of new materials for rehabilitation and conservation of historical monuments supported through further studies. Particulate matter is a potential threat to original structure material of rehabilitated monuments due to soiling and chemical reactions from harmful compounds inside the particles or on the surface between the particle and the deposited surface. Inside of the historical monument, the organic compounds and soot in PM, deteriorated the surface of old ruins, behave a very attractive medium for SO2 capture (this was observed by soiling the structure surface). The ICP-MS analysis was highlighted a rich particles content in iron (6.06-7.25 ng/m3 inside and 75.90-107.80 ng/m3 outside) and manganese (3.10-5.17 ng/m3 inside and 12.80-23.80 ng/m3 outside) and this demonstrated an accelerated oxidation process on the surface of ruins structure. The higher content of metals was detected in suspended particulate matter collected in summer, in comparison of those sampled in winter. Regarding the place, inside and outside of monument, the amount of investigated metals (i.e. Pb, Cd, Cr, Ni, Cu, Mn, Al, Zn, and Fe) was higher outside and this finding may result from the fact that most of metals are accumulated in the finest fraction of PM2.5-10. The measured values of element amount expressed as maximum/minimum/median/mean in analyzed particulate matters were ~ 4-13 times higher for all metals outside comparative with the values obtained for samples collected inside of historical monument.
Acknowledgments: Work was supported by a project of Romanian National Authority for Scientific Research, UEFISCDI, project 51PCCDI/2018 New diagnosis and treatment technologies for the preservation and revitalization of archaeological components of the national cultural heritage.
Control of leaded-paints is one of the world-wide emergencies now a day. Despite administrative control in the maximum lead content in house paints, the presence of leaded-paints in old buildings and houses remains a hot environmental topic. The need for an inspection tool that allows for the extensive screening of samples that could offer a right balance between affordability and exactness is the challenge.
Electrochemical methods provide the solutions to such a challenge but have the disadvantage of employing mercury as the electroactive platform for the analysis. A greener alternative to mercury is bismuth, buy its application for lead analysis in paints has not been validated yet. With the use of adequate reference materials containing certified amounts of lead and certified absence of lead, we designed an electrochemical method based on square-wave anodic stripping voltammetry on bismuth electrodes for the analysis of lead in paints after an ultrasound acid extraction. The technique employs a sample mass in the range 50 – 400 mg, acid extraction in a 10 mL volume, and further analysis of an aliquot of the extraction in the electrochemical cell. A linear concentration range was obtained up to 30 µg Pb/L, while a quadratic calibration curve extends to 100 µg Pb/L. The paint matrix does not influence the results within such ranges, and LOD (limit of detection) and LQD (limit of quantification) of 35 mg/kg and 58 mg/kg, respectively, were obtained, with a mean recovery above 98 %. Such values are adequate for the assessment of lead in paints according to the action limits established worldwide: 90 mg/kg for the USA and EU, and 600 mg/kg for MERCOSUR and South America.
As a complementary analysis, paint chips were analysed by Fourier-Transformed Infrared Spectroscopy (FTIR) by the KBr disc method. Signals at 675, 1038, 2864, 2928 and 3532 cm¹ are assigned PbCO₃.Pb(OH)₂, a common compound used in paints. Additional signals assigned to gypsum employed as filler and zinc white employed as a pigment confirm the initial findings.
The proposed methods, along with the use of the Dust Wipe Method (NIOSH #9105) were employed in the assessment of lead in paints in different homes in Montevideo and Canelones (Uruguay) in an interinstitutional programme involving various Ministries and the University. The Dust Wipe Method initially revealed contaminated houses, and the electrochemical and FTIR analysis of the paint sample provided the final analytical evidence on the presence of lead. The easy of the proposed studies allowed for the immediate response which included the re-painting of the contaminated surfaces, and the control of the children in the contaminated houses.
The toxic levels of trace metals in water and sediment present a serious threat to living creatures and humans. The sediment layer and the suspended solids in the surface waters are the most important sources for the mobilization of trace metals through water. Trace metals react with the ligands as dissolved organic matters or retain on solids in water. Kd (L.kg⁻¹), is defined as the ratio between the metal concentration in the solid phase and the concentration in water:
Kd = Cs / Cw (1)
where Cs (mg.kg⁻¹) and Cw (mg.L⁻¹) are the metal concentrations in the solid and water phases, respectively.
In this study, samples of water and sediment phases were collected from nine different locations on the Samanli and the Safran Rivers and from three different points beyond the Yalova coastline for 12 months. Multiple Linear Regression Analysis Model was used to estimate Kd between water and sediment depending Total Organic Carbon and Dissolved Organic Carbon content which were represented as X1 and X2, respectively. The multiple linear equations were given as Y=A*X1+B*X2+C where Y is the Log Kd value for related trace metals. These multiple linear equations and their correlation coefficients obtained for As, Mo and Se were presented in Table 1.
|Metals||Equations||Correlation Coefficients (R)|
|Mo||Y= 0.002*X1+ 0.420*X2-0.332||0.615|
A series of pillared interlayered clays including aluminum and iron has been prepared. Iron exchanged and/or post-pillared clays with Al-Fe solutions have been synthesized with different hydrolysis ratio OH/Metal. These solids have been characterized by XRD and N2 adsorption measurements and tested in the CWPO of aqueous phenol using hydrogen peroxide (30%) as an oxidant under mild reaction conditions. The cooling at 4°C of clay before pillaring increases the basal space from 17.3A° to 18.10A° in the case of aluminum. Iron exchanged before pillaring increases the rate of iron to 15.8% The catalytic tests show that natural clay and aluminum pillared clay MR-Al100 (OH)1.2 are not active despite they have iron ions. Iron exchanged and post-pillared clay with mixed (Al-Fe) solution containing 10% of iron expressed as molar percentage Fe/MR- Al90Fe10(OH)1.2 show 91.5% of phenol conversion, more than 70% of TOC abatement after 12h of reaction and the low iron leaching (0.02%) in the solution.
Microfluidics has been one of the fastest growing fields of research in recent years, as illustrated by the correspondingly large increase in the volume of publications on the subject . An advantage of such devices is their large surface/volume ratios .
By the late nineties, membrane extraction of metals became an acceptable technology for the recovery of metals from waste streams. Moreover, there exist numerous other possibilities that are yet to be explored; the extraction and pre-concentration using membranes offers some unique possibilities, beyond the capabilities of conventional means, particularly in the field of automated analysis. The challenge in the future lies in enhancing selectivity, testing diverse analytes and incorporation in lab-on-a-chip devices [3,4]
The purpose of this research is to develop a microfluidic membrane module that incorporates a conventional flat sheet plasticized polymer membrane to employ it for the micro-scale facilitated transport of divalent ions (Zn(II), Cu(II)).
Microfluidic membrane extraction includes an extraction module and a peristaltic pump for liquid delivery. The total surface area of the micro-channels is 1.64 cm2.
The flat sheet membrane used here is a polymer inclusion membrane (PIM) containing Cyanex 302 as an extractant.
The flow rates of the donor and the acceptor phases were varied between 50 µLmin-1 and 910 µLmin-1. Optimum donor and acceptor flow rates were found to be 910 µLmin-1and 50 µLmin-1, respectively.
The extraction efficiency (EE) in the static mode varied from 32 to 66%, while in the dynamic mode it ranged from 19 to 79%.
Membranes containing Cyanex 302 showed a high extractive affinity to Zn (II) ions over Cu (II) and Fe (II) ions, and TOPO is strictly selective to Zn (II) ions.
The development of the hydroelectric sector in the Amazon has sparked scientific discussions about the impacts on human health. Riverside communities, which have fish as an important source of animal protein, have the ingestion of fish as the main route of human exposure to mercury. This study investigated the possible health effects associated with environmental exposure to mercury in the population of the upper Madeira River region, Rondônia.
It used the cross-sectional epidemiological design survey, based on recall food consumption based on 7 days of the frequency of fruit and fish consumption. The study contemplates the river and operative phases depending on the implementation of a hydroelectric power plant in the region. The levels of foodborne environmental exposure to mercury were evaluated by dosimetry of total mercury in hair samples. Dosimetry of total mercury (Hg) used direct analysis equipment of mercury SMS 100/Perking Elmer.
The sample universe was composed of 3.399 participants aged between 1 and 100 years (mean: 35.76 ± 15.46). The time of residence of these people in the region was mostly (40.0%) from 1 to 5 years, and 32.4% over than 10 years. In this sample universe, 56% have a low level of education. Beef ingestion (71%) was the main source of animal protein, followed by chicken (17%), fish (10%). Mercury concentrations in the sample universe varied between 0.12 and 50.16 µg g-1 (mean: 3.39 ± 3.06 µg g-1) and the median of 2.62 µg g-1, when stratified the concentrations in the river phase varied between 0.31 and 50.16 µg g-1 (mean: 3.78 ± 3.92 µg g-1) with a median of 2.69 µg g-1 and in the operation phase between 0.12 and 35.62 µg g-1 (mean: 3.27 + 2.10 µg g-1) with a mean of 2.57 µg g-1. The stratified analysis according to the gender variable shows a highly significant difference (p < 0.0001) in the exposure to mercury in the group of women (mean: 3.10 ± 2.70 µg g-1 for river phase and mean: 3.05 ± 2.00 µg g-1 for operative phase) when compared to the group of men (mean: 4.23 ± 4.51 µg g-1 for river phase and mean: 3.40 ± 2.16 µg g-1 for operative phase. The lower human exposure observed over time to female extract may be associated with the fact that rudimentary gold mining activity using mercury is performed exclusively by men. Thus, they accumulate a double exposure: natural environmental (via food) and occupational (via respiratory). The total mercury concentration determined in the hair samples are directly related to the age of the population (p < 0.0001) and consume fish.
Mercury dosimetry showed that 92% of the participants are in the exposure extract below 14 µg g-1 of mercury per gram of hair, the limit recommended by the World Health Organization. The average mercury concentrations found in the hair samples showed values below the overall averages observed in several regions of the Amazon, probably because it is a population the Amazon of roads (urban centres).
Transition metal dichalcogenides (TMDs) as MoS₂ and WS₂ are easily exfoliated in a range of solvents obtaining 2D nanomaterials. Fluorescent molecules usually quench their emission upon interaction with these surfaces. Herein we show that the interaction of the thiabendazole (TBZ), a widespread used fungicide of the benzimidazole family, with nanosheets of TMDs leads to a significant increase of the fluoresce yield in aqueous solutions. Figure A shows the fluorescence emission spectra recorded from TBZ aqueous solution in absence and in presence of MoS₂ and WS₂ exfoliated in two solvents. Without 2D nanomaterial (spectrum a), TBZ solution presents fluorescence but, surprisingly, this initial fluorescence signal increases in a great extent in the presence of all the TMDs materials assayed (curves b-g). When other fluorescent members of benzimidazole family and quinine are additionally assayed with TMDs, the fluorescence suppression is observed, the same as when TBZ is measured with graphene oxide, i.e. the common behaviour.
This surprising effect is rationalized by DFT calculations in which one of the preferential TBZ adsorption configurations shows the molecule interacting with the substrate via its terminating S-atom, as shown at the bottom of Figure B. This interaction induces a net molecular distortion characterized by a TBZ bending after adsorption, which has a clear reflection on its electronic and excitation properties. For the case of the free TBZ (upper part Figure B), both HOMO and LUMO are located in the benzimidazole group making efficient the fluorescence of the free molecule. This scenario is maintained when the TBZ molecule is adsorbed on the TMD substrate but, in this case, the molecule/substrate interaction is mainly driven by a mixture of a sort of substrate/adsorbate Pauli repulsion with the electrostatic anchoring, being able to slightly disrupt the adsorbed molecular geometry to redistribute the molecular LUMO from the thiazole group toward the fluorescent benzimidazole group, which dramatically improves the efficiency of the fluorescence, just as observed in solution.
A linear dependence of the emission with the concentration of TBZ in solution is also found, which combined with the specificity of the process, allows developing a highly sensitive and selective method towards TBZ determination that is applied to real river water samples. An excellent detection limit of 2.7 nM, comparable to the best performing reported methods, is obtained with very good accuracy (Er ≤ 6.1%) and reproducibility (RSD ≤ 4.1%).
Legacy persistent organic pollutants (POPs) and contaminants of emerging concern (CECs) are introduced into the environment by various anthropogenic activities and their chemical and physical properties allow them to enter marine, freshwater and/or terrestrial food webs, where they can be magnified. Top predators play a key role in monitoring contaminants because they bioaccumulate chemicals
in their tissues and organs and can integrate exposure to contaminants over time and over relatively large areas.
Understanding the occurrence, levels and drivers of target contaminants in top predators is therefore fundamental not only for their conservation but also for their potential use as sentinels in environmental monitoring studies due to their high trophic position in food webs. In September 2018, researchers from various European institutions started the LIFE APEX project,
funded by the European Union under the LIFE programme (ENV/SK/000355) to demonstrate the “Systematic use of contaminant data from apex predators and their prey in chemicals management” (https://www.lifeapex.eu).
One of the objectives of this project is to define predominant chemical mixtures in the environment. To achieve this aim, the reference laboratories for LIFE APEX (University of Athens,
Environmental Institute, University of Florence and Fraunhofer IME) have applied strong quality control and quality assurance protocols to extract, purify and analyze samples using different chromatographic techniques, coupled to high resolution mass spectrometry, for the determination of legacy POPs and thousands of CECs in a first set of top predator and prey samples. Samples
(liver and tissues) from harbour seal, Eurasian otter, common buzzard and different fish species have been provided from European Specimen Banks, Research Collections and Natural History Museums and selected to provide a spatial distribution across selected sites in Northern Europe (United Kingdom, Germany, Netherlands and Sweden).
The detected substances have allowed characterization of predominant chemical mixtures in the environment. Through this and other planned work, LIFE APEX will demonstrate how monitoring data from top predators and their prey can play a key role in a better prioritization of hazardous substances, improve chemical risk management, and strengthen regulation and mitigation
The micro mineral pollutants are discharged into nature thus involving risks of harmfulness with respect to the living organisms in the recepteurs. The discharge of toxic metals into environment is a serious problem facing numerous industries. So the search for extraction techniques to remove those heavy metals are increasing interest. Liquid membranes have shown great potentiel in this way especially in cases where metal concentrations are relatively low and other techniques cannot be applied efficiently. The fundamental parameters influencing the transport of the chrome, copper and lead, through the liquid membrane containing different extractant: TOPO; HDEHP and TOA as carriers have been examined (the acidity, nature of the extractant and the time of transportation).
The study of chemical parameters have allowed us to obtain the variables giving the optimum extraction efficiency for diluted solutions of Cr(III), Cr(VI), Cu(II) and Pb(II).
The chemical variable survey permitted us to determine optimum outputs, to understand the mechanisms of extraction were investigated and the phenomena of transfer put in game.
A chemical modelization has allowed to demonstrate the extraction mechanism and transport.
A physical modelling has permitted to identify the existence three phases of transfers that finds their origin on the one hand, in a gradient of potential chemical and, on the other hand, in the active transports bound to the processes
Molecularly imprinted polymers (MIPs) have been fabricated for the selective solid phase extraction (SPE) of diclofenac from aqueous samples. Diclofenac is an anti-inflammatory with both human and veterinary applications. It has been banned for veterinary use in several South Asian countries where vulture populations have dropped significantly due to diclofenac poisoning[1,2]. It has since been added to EPA watchlists as an emerging contaminant, and as such, improved methods for its rapid detection are of a high priority.
Imprinted cavities in a MIP promote the selective uptake of a chosen template molecule into the polymer network. In this study, MIPs comprising acidic and basic functional monomers are investigated as SPE sorbents. A number of the synthesised MIPs exhibit preferential diclofenac adsorption versus corresponding non-imprinted polymers (NIPs) prepared in parallel. Loading and extraction is carried out using a mini-column and sample delivery pump, as well as off-line in standard SPE cartridges. The influence of several parameters on the rebinding performance of the MIPs is investigated, such as sample contact time/flow rate, sample pH, and polymer composition. Emphasis is placed on green chemistry principles and efforts are made to reduce the use of organic solvents where feasible, in addition to enhancing compatibility with previously developed electrochemical sensors. Good sample recoveries (>98%) have been obtained using the developed method.
 Oaks, J. L. et al. Diclofenac residues as the cause of vulture population decline in Pakistan. Nature 427, 630–633 (2004).
 Green, R. E. et al. Collapse of Asian vulture populations: Risk of mortality from residues of the veterinary drug diclofenac in carcasses of treated cattle. J. Appl. Ecol. 43, 949–956 (2006).
Bisphenols are a group of chemicals with two hydroxyphenyl functionalities. They are widely used in production of plastics and polymer resins. Due to the massive utilization of plastics, bisphenol A and its analogues became ubiquitous in the environment and are counted as quasi-persistent. Meanwhile, their endocrine-disrupting action  and for some species, cytotoxicity and genotoxicity were reported. Bisphenols A, AF, AP, BP, C, G, M, and Z are subject of the present study.
Solid phase extraction (SPE) is the method of choice for sample cleanup and preconcentration in the majority of analytical determinations of bisphenols. Consequently, novel sorbents for SPE are continuously being developed. Among them, nanofibers are very promising materials [2, 3]. However, their use in a column format comes with the problem of irreproducible filling and high back pressure. The alternative disc format might not provide the desired sorption capacity. The problems result from the lack of the necessary rigidity. Also, the pore accessibility is impaired when the nanofibers are packed. Thus, they are not well-suited for dispersive SPE due to their tissue-like nature. Therefore, we aimed at a new approach of handling nanofibers for SPE procedures.
3D-printing is a common technology with virtually unlimited possibilities for design and applications in a variety of fields including analytical chemistry . Using 3D-printing technology, we designed a cage-like holder in which the fibers are loosely accommodated that also incorporates a magnetic stirring bar. This way, we took advantage of the lacking stiffness but high robustness of the fibrous sorbent material and achieved reproducible filling of the device with it.
Polycaprolactone among a variety of polymer materials used for the preparation of microfibers produced the best sorbent. The extraction procedure included the following steps: immersion of the stirrer cage with microfibers in 100 mL sample followed by magnetic stirring extraction for 50 min, washing the stirring cage with water, and stripping the analyte with methanol for 35 min. The methanol phase was then transferred to HPLC analysis after 1:1 dilution with water. Gradient elution with acetonitrile and 0.1% phosphoric acid and UV detection was carried out as the final step. Excellent linearity (R2 0.999 – 1.000) over a range of 5-100 ppb was achieved. The limits of detection (0.3 - 0.9 ppb) and quantitation (0.8 - 3.0 ppb) were comparable or better than those reported using previous methods. Recoveries ranged between 44% and 91% for different bisphenols with a preconcentration factor of 20.
This work was supported by the STARSS project (Reg. No. CZ.02.1.01/0.0/0.0/15_003/0000465) co-funded by ERDF. The authors also acknowledge the support of the Czech Science Agency through project No. 17-08738S.
 Z. Zhang, J. Zhang, Y. Wang, Y. Tong, L. Zhang, Talanta 167 (2017) 428-435.
 E.M. Reyes-Gallardo, R. Lucena, S. Cárdenas, Trends Anal Chem 84 (2016) 3-11.
 M. Háková, L.C. Havlíková, P. Solich, F. Švec, D. Šatínský, Trends Anal Chem 110 (2019) 81-96.
 B. Gross, S.Y. Lockwood, D.M. Spence, Anal Chem 89 (2017) 57-70.
Ten years after its introduction, dispersive liquid-liquid microextraction (DLLME) has become the state-of-the-art methodology for sample preparation. In particular, it is appreciated as the fast and easy-to-use technique for analyte preconcentration and sample cleanup. Moreover, various approaches to automated DLLME have been reported including analytical flow techniques . However, no report is available describing the feasibility of DLLME from the point of view of continuous sample flow with stationary organic phase in spite of the potential to reach high and controlled preconcentration factors.
Our poster reports for the first time on continuous magnetic stirring-assisted dispersive liquid-liquid extraction as a new pre-treatment approach for large sample volumes. This procedure was automated using the Lab-In-Syringe (LIS) technique  that used the void in the syringe flow-through chamber, which was enabled by a secondary access to the syringe void through the syringe piston .
Mono-nitrophenols, belonging to priority environmental contaminants, were selected as the model analytes and extracted in-flow from up to 24 mL surface water in a small and constantly dispersed volume of 1-octanol. To evaluate the extraction performance, dispersive back-extraction to an aqueous acceptor phase was carried out followed by a simplified approach to multivariante spectrum analysis, which included baseline modelling to compensate for back-extract spectral background related to humic substances.
The approach, optimization, and analytical performance enabling sub-micromolar limits of detection for all analytes back-extracts are presented. Limits of detection of 0.14, 0.26, and 0.02 µmol L-1 and enrichment factors of o-, m-, p-nitrophenol 19, 25, and 21 were obtained for o-, m-, and p-nitrophenol, respectively, under optimized conditions with relative standard deviations generally less than 5%. Average recoveries of o-, m-, p-nitrophenol from spiked surface water were 94, 82, and 92%, respectively .
B. Horstkotte acknowledges the financial support by the Czech Science Foundation by Project No. 301/17/05409S. The work was supported by the project EFSA-CDN (No. CZ.02.1.01/0.0/0.0/16_019/0000841) co-funded by ERDF.
 M. Alexovič, B. Horstkotte, I. Šrámková, P. Solich, J. Sabo, TrAC 86 (2017) 39-55.
 B. Horstkotte, R. Suárez, P. Solich, V. Cerdà, Anal. Chim. Acta 788 (2013) 52-60.
 I. Šrámková, B. Horstkotte, H. Sklenářová, P. Solich, S.D. Kolev, Anal. Chim. Acta 934 (2016) 132-144.
 K. Fikarová, B. Horstkotte, H. Sklenářová, F. Švec, P. Solich. Talanta 202 (2019) 11-20.
We present the optical sensing of phthalate esters (PAEs), a group of endocrine disrupting chemicals (EDCs). The sensing takes place as changes in fluorescence emission of aminopyrene covalently bound to the organic ligands of the Metal-Organic Framework compound ZIF-8. In the presence of PAEs a quenching of the fluorescence emission is observed. We evaluated strategies to engineer colloidal size distribution of the sensing particles to optimize the sensory response to PAEs. Thorough characterization of the modified ZIF-8 nanoparticles included PXRD, TEM, HPLC and Photophysical characterization. The presented capability of the fluorophore functionalized ZIF-8 to sense PAEs complements established methods such as chromatography-based procedures, which cannot be used on site and paves the way for future developments such as hand-held quick sensing devices
Tomato is one of the most cultivated and consumed vegetables worldwide, and a basic ingredient for kitchens in many cultures, not only as the fresh vegetable but also as several derived foodstuffs: juice, sauces… This product is also commercialized as dried paste or powder. In addition to its socioeconomic importance, the tomato stands out for its high content of bioactive compounds, with beneficial properties for health, phenolic compounds, pigments, antioxidants, and other nutrients in the human diet. The performance and quality of this vegetable are affected by different environmental factors, such as temperature, type of soil... but also by the genotype that for example significantly influence hydrophilic and lipophilic antioxidant activities (1). The evaluation of product quality should include the determination of different types of bioactive components such as those mentioned.
In this sense, fluorescence is a property that a considerable number of these components present and the possibility of using the native fluorescence of the sample itself, without handling it, or with minimal manipulation, is an interesting alternative to evaluate such parameters with the advantages of the increase in the speed of the process and decrease of distortion in the results.
In this study, the total fluorescence spectra (excitation-emission matrices, EEMs) of aqueous extracts of several tomato paste samples were obtained in the front-face mode. The samples were extracted in 10 ml of ultrapure water being the sample size of 1 g. Fluorescence excitation and emission spectra were recorded from 210 to 300 nm and 310 to 390 nm, respectively. These excitation - emission fluorescence matrices of a set of 50 samples were analyzed by the second-order multivariate techniques such as PARAFAC.
Also, the evaluation of hydrophilic compounds in this kind of samples has been performed by HPLC with fluorescence detection, in order to clarify if the compounds responsible of fluorescence signal are phenolic antioxidants. The correlation between the areas of the different peaks obtained in a gradient reversed phase system and the corresponding scores for the main PARAFAC factors was examined to stablish the possibility of using PARAFAC-EEMs to determine hydrophilic antioxidants in these tomato samples.
1.- Lenucci MS, Cadinu D, Taurino M, Piro G, Dalessandro G, J. Agric Food Chem. 2006, 54, 2606-2013. Antioxidant composition in cherry and high-pigment tomato cultivars.
Acknowledgment: Financial support was provided by the Junta de Extremadura (Ayuda GR18041-Research Group-FQM003 and Project IB16058) and Ministerio de Economía, Industria y Competitividad of Spain (Project CTQ2017-82496-P), both co-financed by the European FEDER funds. Samples were provided by Centro Tecnológico Agroalimentario Extremadura CTAEX.
Sudan dyes are phenyl-azoic derivatives widely used as synthetic organic colourants because of their colour fastness and low price. Azo dyes have been extensively used in many industrial applications including for example oils, solvents, and plastics. Sudan I, II, III, and IV have been applied for many years as food colourants in different products, such as chilli powder and sauces, to mimic, intensify, and prolong the appearance of the natural red hues because of their intense red-orange colour. The use of these colourants can constitute a serious health risk. Thus, they are banned for food usage in the European Union since 2004 . Our work aims at development of a fast and sensitive method for the simultaneous determination of sudan dyes (I, II, III, and IV) in chilli products such as powder, sauce, and paste by micellar electrokinetic chromatography-mass spectrometry (MEKC-MS) with ammonium perfluorooctanoate as the volatile surfactant. MEKC separation and MS detection conditions were optimized in order to achieve the fast, efficient, and sensitive separation of all four dyes. Target compounds were extracted from chilli samples with acetonitrile and cleaned by freeze out step achieving excellent results in terms of extraction efficiency and matrix effect. Analytical performance of the method was satisfactory, obtaining limits of quantification lower than 21 μg kg⁻¹ in all cases. The precision, expressed as relative standard deviation (%, RSD) was below 15.7%. The extraction efficiency for fortified samples ranged from 86.5 to 99.8% with RSD lower than 10.3%. Matrix effects were evaluated for all samples studied, being lower than |10|% in all cases. The applicability of the proposed method was successfully tested with 20 chilli products. The content of the sudan dyes was calculated from the corresponding matrix-matched calibration curve and sudan I and IV were detected in two samples at levels of 125 and 0.095 mg kg⁻¹, respectively.
The study was supported by the STARSS project (Reg. No. CZ.02.1.01/0.0/0.0/15_003/0000465) co-funded by ERDF.
 European Union (2004). Commission Decision of 21 January 2004 on emergency measures regarding hot chilli and hot chilli product. Official Journal of the European Communities, L27, 52–54.
Paralytic shellfish toxins (PST) represent a diverse class of potent neurotoxins produced from dinoflagellates and may naturally bioaccumulate in filter-feeding shellfish, which upon consumption can cause human illness. Monitoring of this toxin class in edible bivalves is mandatory in European Union. This toxin group counts more than 50 PST analogues, which represents a formidable analytical challenge demanding high quality analyses to ensure a safe shellfish production for consumers. During the recent years tetrodotoxins (TTXs), highly potent neurotoxins that are traditionally associated with the occurrence of tropical Pufferfish Poisoning, were identified in European bivalve molluscs. This occurrence raised a need to include TTX analysis into the existing methodology for monitoring of marine biotoxins in shellfish. An in-house validation of a method that uses hydrophilic interaction liquid chromatography (HILIC) UPLC–MS/MS analysis of fourteen commercially available PST analogues and three TTX analogues is presented in this poster. Three of the most common bivalve species commercially produced in Swedish waters: blue mussel (Mytilus edulis), oyster (Ostrea edulis) and cockles (Cerastoderma edule) were assessed. Validation results showed satisfactory method performance for linearity, repeatability, selectivity, recovery and in-house reproducibility. Limits of quantification (LOQ) are at low µg STX eq/kg but varies for different toxins. In comparison to the routine regulatory monitoring methods (e.g. AOAC 2005.06 and AOAC 2011.02) that typically employ derivatisation, sample fractionation and complex calculations of a sample´s toxicity the present method avoids these multiple and time consuming disadvantages. The method enables simultaneous detection of each toxin analogue to be resolved and quantified as a single peak. This method, thus, represents an important alternative to the regulatory methods currently used for monitoring PSP toxins and is in our lab advantageously used as a complement to regulatory methods to facilitate and speed up the PSP analyses.
Polycyclic aromatic hydrocarbons (PAHs) are organic compounds having toxic and carcinogenic effects resulting from incomplete combustion of organic compounds. PAHs enter the human body with air, water, foods and cigarette smoke, causing mutation in DNA. More than 100 PAH compounds were detected in nature. In this study, the amounts of PAH in omega-3 fish oil samples from national and international brands to be obtained from pharmacies were determined by high pressure liquid chromatography method (HPLC) for the first time. Polyaromatic hydrocarbon (PAH) compounds in fish oil preparations were extracted by using solid phase extraction (SPE) method and specially produced cartridges for PAHs.
In this study, 4 different PAH molecule, which were pyrene, benzo(a)pyrene, benzo(b)fluoranthene, and chrysene, were investigated in the omega-3 fish oil supplements. The developed method presented good precision with intra-assay and inter-assay, ranged from 4.7 to 14.6 %, and from 7.9 to 21.4%, respectively. Recovery ranged from 89.6 to 102.3% and linearity showed good adjustment presenting determination coefficients (R2) from 0.980 to 0.999. The limits of quantification ranged from 0.02 to 0.05 µg/mL. The proposed method is simple, versatile, allows simultaneous extraction of PAHs, and was successfully applied to the analysis of omega 3 fish oil supplements. It is noteworthy that some of the PAH-determined samples were infant food supplements.
Apiculture faces a great deal of pests, mites, insects and number of important diseases. Beekeepers can protect their honey combs from acarine and wax moths with applying chemical control methods. Chemical control is effective and easy to use and usually is applied as fumigants of nitrobenzene, para-dichlorobenzen, naphtalene, thymol, phenol, benzaldehyde, phenylacetaldehyde. There is a risk of harmful residues in honey, regardless of the type of fumigant. Aformentioned compounds can also be used as bee repellent to simplify harvesting of honey. These substances are adsorbed on the wax and end up in honey. European Regulation No 396/2005 set a limit of 10 μg/kg honey for naphtelene and 1-4 dichlorobenzen where no MRL have been established for other repellents. Although there have been reports on methods to analyse for phenol, naphtelene, dichlorobenzene residues in honey, there are no methods given in the literature to detect all common repellents in honey with single injection. This study describes novel analytical methodology for the quantification of repellents using GC-MS and simplified sample pretreatment approach.
The method involved a single step ethyl acetate extraction of a buffer-diluted honey sample followed by vacuum concentration. The method was applied in a small survey of 40 honey samples from 2018 and from various botanical sources. The calibration curves were established by adding known concentrations of the analytes to a residue-free honey like-syrup sample ranging from 5 to 400 μg/kg. GC inlet was operated in splitless mode (280 °C, 2 μl injection) onto capillary column. Temperature gradient was performed and helium was used as carrier gas at 1,2 ml/min. MS detection was conducted in selected ion electron impact mode and MS transfer line temperatures were maintained at 300 °C.
The method was validated to cover a range of 5-400 μg/kg, achieving mean recoveries at 89-95% with a standard deviation range of 2-6%. The method had a detection limit of 0,005 mg/kg for all molecules. MS response was linear over the range 5 – 1000 μg/kg with correlation coefficients (R2) of 0,998. No sample contained detectable level of nitrobenzene, pDCB or thymol residues. 10 honey samples contained low levels of benzaldehyde and/or naphtalene and 7 of these samples also contained phenol. Maximum concentration were 45.02 μg/kg at honey for benzaldehyde. All honey samples include phenylacetaleyde as a natural compound and cannot be evaluated as residue. This substance can also be generated in honey itself from the amino acid phenylalanine.
The results were showed us the use of pre-contaminated honey comb or usage of bee repellent fumigants can affect the honey quality. The analytical methodology was developed for the determination of repellents in honey is simple, rapid and efficient while GC–MSD analysis enables selective and sensitive detection of these compounds. The proposed method was optimized and validated over a wide range of concentrations for 7 target analytes. Its successful application to real samples indicates that it is simple, fast and cost effective for the analysis of large numbers of samples.
Carotenoids are an important class of bioactive compounds mostly abundant in yellow, orange and red-colored fruits and vegetables. More than 600 carotenoids have been detected in nature, and they are commonly divided into two chemical classes: the carotenes (e.g., α-carotene, β-carotene, and lycopene) and xanthophylls (zeaxanthin, canthaxanthin, astaxanthin and lutein). β-carotene acts as a precursor of vitamin A and is a naturally carotenoid in our diet, which has anticardiovascular, antioxidant, antimutagenic, antiinflamatory and anticancer activities.
A simple, sensitive and selective fluorimetric method for the determination of β-carotene in different food samples was proposed. Some fluorescent dyes were investigated in a sequence of experiments to increase and optimize the response signal for reliable, suitable and sustainable determination of β-carotene. 3′,6′-dihydroxyspiro[isobenzofuran-1(3H),9′-[9H]xanthen]-3-one (Fluorescein) was chosen for fluorimetric determination of β-carotene with an phosphate buffer solution at a pH of 9. Under the optimum experimental conditions, β-carotene can be determined in the range of 0.54 – 536.87 mg L-1 with the detection limit 0.47 mg L-1.
Foodstuff total antioxidant activity is determined with various analytical assays. Corresponding total indices are the rough estimates of antioxidant sum content (cΣ) recalculated to standard substance (Xst). Simple, rapid and high precision FRAP assay  allows to estimate the sum content of phenolic antioxidants (PhA′s) in vines, teas, juices etc. PhA′s are active reducing agents which react with Fe(III) in vitro. The leading role in FRAP assay development belongs to some Turkish (R. Apak, K. Berker, etc.) and Russian chemists. The results of our longstanding investigations to optimize FRAP assay will be summarized in the report. Instead of tripyridyltriazine which was initially used as the subsidiary reagent, other ligands were offered [2, 3]. We usually use o-phenantroline or 2,2′-dipyridil, this selection increases the FRAP assay sensibility. To prevent the nonadditivity of analytical signals, we have proposed to raise the oxidizing reagent concentration . It was established that the main reason of systematic errors is the intragroup selectivity of individual PhA′s signals. This undesirable selectivity is caused mainly by two factors - the different stoichiometry and different kinetics of numerous reactions between Fe(III) and individual PhA′s. The error may be calculated a priori if the sample composition and the nature of Xst are known beforehand . In full accordance with the theoretic forecast we received more accurate cΣ estimates when ascorbic acid was used as Xst and the total index was calculated in mol-eqv/dm³ units . For equal status, the systematic errors of FRAP assay are diminished when the exposition time is decreased. When all these recommendations are taken into account, the B-type relative uncertainty does not exceed 20 % and the whole uncertainty usually does not exceed 30 % rel. . A complementary error is formed in the presence of citrates, tartrates and other substances binding Fe3+ ions in the stable complex compounds .
The important advantage of improved FRAP assay is lack of signals of carbohydrates and other substances, which have no antioxidant properties in vivo. New analytical procedures were examined (metrological validation) and then were recommended to be used in food industry laboratories. The approximate coincidence of the interval estimates obtained for the same foodstuff (black tea) with the different standard substances  makes FRAP assay appropriate not only for calculating the total index “antioxidant activity”, but also for an objective estimate of total PhA content in foodstuff.
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2. Berker K., Guclu K., Tor I., Apak R. Talanta, 2007, 72 (3), 1157.
3. Tsypko T., Petrakova I., Nikolaeva N., Chuprynina D., Temerdashev Z., Vershinin V. Analytics
and Control, 2011, 15 (3) 287 (in Russian)
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5. Tsypko T., Chuprinina D., Nikolaeva N., Voronova O., Temerdashev Z. News of universities.
Food technology, 2011, (5-6), 84 (in Russian).
6. Brilenok N., Bakhareva M., Vershinin V. Analytics and control, 2016, 20 (3) 209.
7. Tsupko T., Brilenok N., Gushchaeva K., Vershinin V. Analytics and Control, 2019, 23 (1) 143
Collard greens are loose-leafed cultivars of Brassica oleracea a common vegetable. The aim of the present study consisted on the one hand in the determination of nutrients (major, minor and trace elements) as well as potentially toxic elements in this plant and on the other hand in evaluating the effects of certain stress (elevated salinity) on the uptake and accumulation of the before-determined elements. This stress factor has severe effects on crop productivity especially in countries in the Mediterranean area. Plants’ growth is determined by the photosynthetic activity, which is strongly influenced by salinity stress. The resultant effects are different for various species or cultivars, duration of the stress and applied salt concentration.
Roots and leaves of normally grown plants and of plants exposed to higher levels of sodium chloride were analyzed in the investigation. More than twenty metals and metalloids were quantified using ICP-OES (inductively coupled plasma – optical emission after acidic microwave assisted digestion of the respective plant sample. Apart from the general determination of the elemental contents and their distribution within the plant, special attention was drawn to the sodium/potassium ratio as well as to changes in the contents of other single charged metal ions.
In areas where there is no natural or anthropogenic problem of arsenic contamination, food intake is the main source of human exposure to arsenic with seafood one of the main contributors. Arsenic can be present in different chemical forms in seafood with varying toxicities and abundances. Total arsenic content is useful to establish if further speciation is necessary to determine the exact concentration of the toxic arsenic species. Methods using concentrated nitric acid already exist for digestion of seafood samples for total arsenic content, but these methods have disadvantages and shortcomings. An extraction method using a deep eutectic solvent (DES) in a digestion block was developed as an alternative green method to the traditional digestion methods. Different choline chloride deep eutectic solvents were prepared and evaluated using a tuna fish certified reference material (CRM, BCR-627). These included choline chloride-oxalic acid, choline chloride-lactic acid, choline chloride-malonic acid and choline chloride-malic acid, all prepared in a 1:1 ratio. Choline chloride-malonic acid was the most efficient with 88% extraction of arsenic from the CRM. Key parameters that were further optimized for the choline chloride-malonic acid DES included composition of the DES (the ratio of choline chloride to malonic acid), volume of DES, temperature, extraction time and the effect of nitric acid concentration and addition after dissolution on the recovery. For the optimized METHOD: 0.1 g of CRM was treated with 4 mL of DES, heated in a digestion block for 10 minutes at 100 °C and treated with 5 mL of 1 M nitric acid before dilution to known volume. Samples were filtered before determination on ICP-MS. Recoveries of around 90% were obtained for the tuna fish CRM. The method was applied for analysis of As in canned tuna samples from different manufacturers.
Sulphites are a class of widespread food additives found in many food products, acting as preservatives to prevent undesirable microbial growth and oxidative processes, improving the quality of the final product and its shelf life. In wine, the addition of sulphites during the winemaking process is a common procedure, in order to stabilize the quality of the final product. When sulphites are added to wine, an acid-base equilibrium is attained in which, depending on the pH, the prominent form can be: SO₂, HSO₃⁻ and SO₃²⁻ . Sulphites, can bind to different wine compounds, forming adducts. This chemical interaction is important to the regulation of the wine bouquet, since it helps to control the undesirable aroma of many naturally existing compounds.
Gas-diffusion microextraction (GDME)  is a sample preparation technique developed and patented in our research group. The extraction process is based on the volatile compounds transfer from the sample through a gas-permeable membrane into a liquid acceptor phase. GDME has previously been used for the analysis of important quality markers in different liquid and solid samples [3,4]. GDME can be combined with labelling (or derivatization) to improve separation and/or detection of the analytes. The use of a labelling reagent in the acceptor phase enhances the extraction selectivity and the enrichment factors.
In this work, GDME combined with HPLC-UV and HPLC-DAD-MS/MS was used to evaluate the effect of breaking the adduct between sulphites and different carbonyl compounds of wine (acetaldehyde, formaldehyde, furfural, hexanal, nonanal, etc.), making possible to determine their free, bound and total contents. Since the target compounds were carbonyls, a derivatization reaction with 2,4-dinitrophenylhydrazine was employed. Different global and individual effects were studied and evaluated in model wine solutions and in wine samples, such as the addition of increasing amounts of sulphites, the stability of the adduct formed and the optimum pH to break the adduct. Finally, the free, bound and total contents of carbonyl compounds was determined in different red, white and rosé samples.
RMR would like to acknowledge Fundação para a Ciência e a Tecnologia (FCT, Portugal) for the Junior Research fellowship CEECIND/04259/2017. The work was also supported by UID/QUI/50006/2019 with funding from FCT/MCTES through national funds.
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 R. M. Ramos, L. M. Gonçalves, V. Vyskočil, J. A. Rodrigues, Talanta, 2017, 169, 203.
 P. F. Brandão, R. M. Ramos, P. J. Almeida, J. A. Rodrigues, J. Agr. Food Chem. 65, 2017, 1037.
Florfenicol, a synthetic analog of thiamphenicol, is a veterinary medicine with the same mode of action as chloramphenicol. Florfenicol is widely used as veterinary antibiotics for the treatment of bacterial infections in animals and is also available in the aquaculture. People ingesting fishery food exposed to florfenicol have a possibility to be exposed to it unintentionally and it might be potentially hazardous. Proficiency test was conducted for optimizing a method for determining florfenicol and its metabolite, florfenicol amine, in the fishery products. The proficiency was evaluated at three concentrations, 0.005, 0.010 and 0.020 mg/kg in three fishery species; shrimp, flatfish and eel. Extraction was performed with acetonitrile and purified with C18 and primary secondary amine (PSA). Samples were analyzed using Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS/MS). Recovery rates (n=5) in each spiked samples were obtained for 88.8~107.9% with ≤7.86 CV%, 102.9~110.3% with ≤8.07 CV% and 100.13~108.76% with ≤7.05 CV% in the shrimp, flatfish and eel, respectively. Matrix effects were negligible interfering peaks around the retention time of florfenicol and florfenicol amine. Linearity of calibration curves in each matrices was higher than 0.998 (r²). The limits of quantification of the method were determined as 0.005 mg/kg. Monitoring of florfenicol residues was conducted for three species of fishery food collected from the local market in South Korea. In conclusion, 20 samples or more were analyzed, and quantities of florfenicol and florfenicol amine were determined whether residues exceed Maximum Residue Limits (MRLs). This research was supported by the grants (19161MFDS581) from Korean Ministry of Food and Drug Safety in 2019.
Marine environment with healthy ecological and chemical status guarantees protection of human health and biodiversity. Worldwide, fish and seafood products are highly consumed and present source of basic nutrients. However, highly toxic mercury species tend to have high bioaccumulation factors in marine food chain. Health authorities strictly monitor the state of marine environment and biota. The European Union has established maximum permissible level for total mercury (THg) in fishery products as low as 0.50 mg/kg. This requirement imposes for reliable, sensitive and easy-to-use methods for determination of traces of mercury in complex matrices. Inductively coupled plasma mass spectrometry (ICP MS) is known for its high sensitivity - determination of total mercury at sub-mg/L level; however, in complex matrix, as seafood products, the precision is questionable. Advanced Mercury Analyzer allows direct determination of THg without additional sample preparation. This method is to be used for testing materials, whose THg concentration, for a given mass, exceeds a detection limits of approximately 0.01 ng Hg.
This report presents a comparative study on determination of THg by Advanced Mercury Analyzer (AMA) and three different mass spectrometry techniques: ICP-MS High Resolution technique, classical quadrupole ICP-MS technique and Gas Chromatography coupled to Inductively Coupled Plasma High Resolution Mass Spectrometry (GC-ICP-HR MS) to determine the monomethylmercury (CH3Hg+) and inorganic mercury (Hg2+). The results were obtained with isotope dilution (ID) calibration approach as a primary method of measurements.
The analytical performance of the studied methods was optimized analyzing Certified Reference Materials – IAEA 452 (Scallop tissue), NIST 2976 (Mussel tissue) and NIST 1566b (Oyster tissue). The found concentration of THg in NIST 2976 (reference value 61.0 ± 3.6 µg/kg) was 61.2 ±3.5 µg/kg and 61.0 ±7.9 µg/kg obtained by AMA 254 and ID-ICP-MS, respectively. Monomethylmercury in NIST 1566b (reference value 0.0132± 0.0007 mg/kg) was 0.0139 ±0.0017 mg/kg obtained by ID-GC-ICP-HR MS.
Gammarus and Sea Bass were analyzed during the study. The total mass fraction of mercury in Sea Bass sample, was 0.685±0.030 mg/kg with AMA, 0.724±0.016 mg/kg obtained by ID-ICP-MS, 0.698±0.059 mg/kg with ID-ICP-HR MS and 0.708±0.070 mg/kg obtained by ID-GC-ICP-HR MS. Total mercury in Gammarus sample was 0.22 ± 0.05 mg/kg, 0.21 ± 0.01 mg/kg and 0.20±0.01 mg/kg obtained by AMA 254, ID-ICP-MS and ID-ICP-HR MS, respectively.
The presented results were in good agreement with the reference values and showed that four analytical methods provided comparable results for content of total mercury, monomethylmercury and inorganic mercury in biota samples.
Acknowledgements: This study is support by the EURAMET under the EMPIR Researcher Mobility Grant through the project “16RPT01-RMG1”
Metals are ubiquitously in the environment, hence they are found in the food chain and in all the raw materials used for oral formulations and whatever may be ingested by humans. Several metals may sometimes present high risks of toxicity to humans, even with irreversible effects. Some of them are toxic at any concentration, other become dangerous over a concentration limit. Hence, it is very important to determine these species down to trace and ultra-trace concentration levels.
Herbal medicines/remedies are certainly an integral part of the food chain. These products are worldwide used every day by several millions of people for a number of reasons: nutritional, medicinal, but also to obtain performance-enhancing effects. Heavy metals such as, for example, mercury, copper, lead, cadmium, zinc, nickel, arsenic and thallium have been found as ingredients in certain remedies. Unfortunately, due to the unregulated nature of the manufacture of herbal medicines, potentially lethal concentrations of these elements may occur. The International Organizations recommend that medicinal plants used as raw materials for the finished products may be checked for the presence of toxic metals. Maximum permissible limits are set, paradoxically, only for mercury (1 ppm), lead (10 ppm), cadmium (0.3 ppm) and arsenic (10 ppm). A decision about the permissible limits for other metals has not been taken yet, because many of them are considered, sometimes even incorrectly, as micronutrients.
Among metals, thallium is becoming increasingly important, considering both its continuous increase in the environment and its very high toxicity for humans. Thallium is released into the atmosphere from both natural and anthropogenic sources. Its presence in the environment is prevalently linked to the erosion of soils containing thallium-based minerals and volcanic emissions. The anthropogenic activities most responsible for the introduction of this metal into the atmosphere concern the mineral smelters, the cement factories and the coal-burning facilities. Last but not least, also agricultural practices are responsible for environmental pollution by thallium.
The present paper reports, for the first time, an electroanalytical procedure for the voltammetric determination of ultra-trace thallium(I) by square wave anodic stripping voltammetry (SWASV) in herbal medicines, using a conventional three-electrodes cell: a stationary hanging mercury drop electrode (HMDE) as working electrode, and a platinum electrode and an Ag/AgCl/KClsat electrode as auxiliary and reference electrodes, respectively. The analytical procedure was verified by the analysis of the standard reference materials. Precision and trueness, expressed as relative standard deviation and relative error, respectively, were generally lower than
7% in all cases. Once set up on the standard reference materials, the analytical procedure was transferred and applied to commercial herbal medicine samples, and a critical comparison with spectroscopic measurements was done to evaluate the analytical performance.
The sugar content of certain foods and drinks is controlled by European legislation (Neeley, 1972). As sugars are
known to play a vital role in the progression of major health problems (e.g., obesity) and diabetes disease, their
total or single (especially glucose) identification is an analytical challenge. Sugarsweetened soft drinks,
constituting the largest single source of calorie-rich U.S. diet and increasing the risk of obesity, require special
investigation and monitoring (Apovian, 2004). The reducing properties of monosaccharides and disaccharides, as
environmentally friendly materials, have also allowed the synthesis of nanoparticles, and there are numerous
metal nanoparticle synthesis methods in the literature related to this advantage. Thus, it was the aim of this work
to combine the economic and environmentally friendly nature of AgNP synthesis using saccharides with the
determination of reducing sugars in a simple and practical nanocolorimetric assay. The principle of the method
relies on the formation of silver nanoparticles by the reduction of the Ag + ion in the presence of aqueous ammonia
and sodium hydroxide to zerovalent silver (Ag 0 ) by reducing sugars. Although there are a number of nanoparticle-
based determination methods for reducing sugars in the literature, it is not possible to adjust the particle size and
distribution in alkaline solution necessarily used for sugar oxidation, which could only be made feasible by the
Tollens reaction incorporating ammonia for alkalinity. Thus, a single analytical wavelength with excellent linearity
of response was achieved. The limit of detection of the developed method was at the nM level, and both the linear
correlation coefficient (r = 0.9999) of the calibration study and the molar absorption coefficient (ε = 1.5 × 10 5 L
mol −1 cm −1 ) were satisfactory for glucose as the representative compound. The proposed method could be
selectively applied to various synthetic mixtures of reducing sugars with polyphenolic compounds, and to honey,
milk, and commercial fruit juice as real samples using solid phase extraction as a clean-up process. The method
has also been validated against the alkaline CUPRAC method (Başkan et al., 2016) as the reference method of
reducing sugar determination established in the literature. The recommended method is simple and cost-effective,
which can conveniently be applied even in traditional laboratories because of the easy accessibility and low cost
of the reagents used. It is believed that this work may open the way to innovative studies employing
nanotechnology in sensitive and linear-response sensing of reducing sugars.
Apovian, C. M. (2004). Sugar-sweetened soft drinks, obesity, and type 2 diabetes. Jama, 292(8), 978-979.
Başkan, K. S., Tütem, E., Akyüz, E., Özen, S., & Apak, R. (2016). Spectrophotometric total reducing sugars assay
based on cupric reduction. Talanta, 147, 162-168.
Neeley, W. E. (1972). Simple automated determination of serum or plasma glucose by a hexokinase/glucose-6-
phosphate dehydrogenase method. Clinical Chemistry, 18(6), 509-515.
Bioactive thiols play an important role in many crucial biological processes; they are considered important biomarkers and are intimately related to numerous diseases. L-Cysteine (L-Cys), one of the main biothiols, is a common nonessential amino acid, whose deficit may cause skin alterations, edema, heart diseases, psoriasis and weakness. Due to the importance of this amino acid, it is fundamental to develop simple, selective and sensitive analytical methods for its quantitation. The use of luminescent systems that make use of lanthanide ions (called Lanthanide-Sensitized Luminescence, LSL) has been very important within the field of Analytical Chemistry due to the high sensitivity and selectivity of the methods developed. The implementation of nanoparticles, such as silver nanoparticles (Ag NPs) and graphene quantum dots (GQDs), in LSL-based analytical methods can provide additional characteristics such as sensitivity and selectivity.
We propose two analytical methodologies that make use of Tb(III)–GQDs and Tb(III)-Ag NPs complexes as luminescent probes. Both systems are based on the quenching effect that L-Cys provokes on the time-resolved luminescence of lanthanide-nanoparticles systems. L-Cys also quenches the luminescence of terbium ions; however, the introduction of the mentioned nanoparticles produces important increases in sensitivity. The method proposed present linear dynamic ranges of 0.3-5 µg mL⁻¹ for Tb(III)-Ag NPs and 0.05-3 µg mL⁻¹ for Tb(III)-GQDs, with limits of detection of 0.09 and 0.015 µg mL⁻¹, respectively. The proposed luminescence probes were applied to the determination of L-Cys in food supplements, obtaining satisfactory results.
In the Food Industry, it is estimated that around 30 – 40% of fruits and vegetables are loss during postharvest due to mishandling, spoilage and pest infestation. As a consequence, quality problems may appear such as physiological deterioration in the form of oxidation reaction such as browning reactions or fungal infection.
In this aspect, plastic materials (e.g. plastic films) have been used for the food industry to reduce fruits and vegetables losses, therefore, maintaining quality and extending the shelf life of the product. However, the excessive use of plastic has had a negative impact on the environment due to their non-biodegradable nature. Therefore, it is imperative for the food industry to search for alternative to plastic materials to develop new food packaging such as active films to be used on fruits and vegetables.
In addition, the use of synthetic additives during the production of plastic containers such as butylated hydroxyanisole (BHA) or butylated hydroxytoluene (BHT), which have been shown to have harmful effects on human health, has highlighted the need to look for safer and more efficient packaging alternatives and additives. Therefore, in recent years the food industry has been searching for new materials and on the other hand, additives that can respond to changing market needs, resulting in active packaging and obtaining active compounds from agro-industrial waste, respectively. The Chilean chestnut industry (Castanea sativa Miller) presents a great opportunity as a renewable source for the generation of active compounds that could be used as new raw materials for the development of a novel biodegradable active film.
Thus, the objective of this study was to characterize the shells of the Castanea sativa Miller fruit grown in Chile for the identification of active compounds with antioxidant activity. Hence, through the use of an experimental design, optimal conditions were obtained for the extraction of compounds with antioxidant activity from chestnut shells (Castanea sativa Mill.). Then, the antioxidant properties of chestnut extracts (Castanea sativa Mill.) obtained were evaluated through several chemical tests: DPPH, ABTS and FRAP. Also, the contents of flavonoids, o-diphenolic compounds and tannins were also obtained. Finally, the compounds present in the extract were separated and analyzed using HTPLC-ESI-MS.
The results showed that the optimal conditions to extract antioxidant compounds from chestnut shell were 50% ethanol extracted for 30 minutes at room temperature. In relation to antioxidant activity, it was obtained 902.9 and 761.0 mg Trolox/g equivalents, for ABTS and DPPH respectively, and 229.2 mg ascorbic acid equivalents /g for FRAP. The content of flavonoids, o-diphenolic compounds and tannins was determined, these being 384.17 mg catechin/g equivalents, 302.71 mg caffeic acid equivalents/g and 123.18 mg gallic acid equivalents/g, respectively. Finally, the compounds tentatively identified by HPTLC-ESI-MS responsible for the antioxidant activity were classified as phenolic compounds, coumarins and flavonoids.
In Chile, honey production is one of the most important emerging industries supporting many small farmers. Its qualities depend on the flowering of the place where the beekeeping activity takes place, which produces differences between honeys in terms of their macroscopic characteristics and physicochemical properties. These differences would give honeys a unique characteristic. One of these differences would be the carbohydrate profile present in honeys. Thus, the objective of this work is to characterize the carbohydrate profile present in honeys commercialized in the Bio-Bio region through HPTLC. Specifically, the following sugars were analyzed: Glucose, Fructose, Sucrose, Isomaltose and Erlose. The HPTLC method for the analysis of these sugars was optimized and validated according to the ICH standard for linearity, repeatability, limit of detection and limit of quantification.
An HPTLC chromatographic method was implemented for the detection and quantification of glucose, fructose, sucrose, isomaltose and erlose in honey (Apis mellifera L.). The mobile phase used was as follow: chloroform+ acetic acid + water (7+6+1 v/v) + acetonitrile + water (80+20 v/v) using an automatic development chamber. Under these conditions, it was possible to separate all the sugars considered.
The method was linear for glucose (8.5 - 51.4 ng/band), fructose (18.4 - 110.3 ng/band), sucrose (25.7 - 128.7 ng/band), isomaltose (26 - 130 ng/band) and erlose (87.8 - 438.8 ng/band). In relation to repeatability, this was less than 5% for all sugars. The detection and quantification limits were: 1.73 and 8.66 ng/band for glucose; 0.68 and 3.40 ng/band for fructose; 2.44 and 8.12 ng/band for sucrose; 0.33 and 1.12 ng/band for isomaltose; and 0.08 and 0.42 for erlose, respectively.
When the method was applied to the analysis of commercial honeys (n=15) from the Bio-Bio region, the following results were found: 191.49 - 327.13 g/kg glucose; 310.32 - 408.32 g/kg fructose; 8.49 - 18.62 g/kg sucrose; 21.13 - 214.73 g/kg erlose; 7.21 - 34.21 g/kg isomaltose.
Honey is a natural food product of great benefit to human health. It characterised by a complex composition. Although it consists mainly of sugars and water, it also contains about 200 substances in smaller amount such as enzymes [1, 2]. Enzymes present in honey are mainly produced in the hypopharyngeal glands of the bees (animal origin). Other possible origins could be nectar, honeydew and pollen (vegetal origin) or honey microorganisms . Invertase (α-glucosidase) is one of the most important honey enzymes, it hydrolyses sucrose into fructose and glucose during honey ripening process. Invertase activity can be used for characterising the quality and freshness of honey because this enzyme is the most sensitive one to thermal treatment. It can indicate the aging or overheating of the honey, but it may give information about adulteration as well.
Our aim was to develop a novel analytical method for the fast determination of invertase activity that can be used during quality control of honey samples. Our assay based on the application of an artificial substrate, namely p-Nitrophenyl-α-D-glucopyranoside. p-Nitrophenol produced by the enzyme reaction is detected by amperometric method which is much more sensitive than the traditional spectrophotometric determination .
Screen-printed carbon electrodes (DropSens, Spain) and a QuadStat 164 potentiostat (eDAQ, USA) were used for amperometric measurement. Our measuring system worked in flow injection system. The measuring parameters (polarization potential, pH, temperature, etc.) were optimized. The applicability of the method was tested by analysis of honey samples.
Acknowledgments: This research was supported by the grant EFOP-3.6.1-16-2016-00001 (“Complex improvement of research capacities and services at Eszterhazy Karoly University”).
 O. Escuredo, M. Míguez, M. Fernández-González, M.C. Seijo (2013) Food Chemistry, 138, 851–856.
 P.M. da Silva, C. Gauche, L. V. Gonzaga, A. C. Oliveira Costa, R. Fett (2016) Food Chemistry, 196, 309–323.
 A. A, Machado De-Meloa, L. B. de Almeida-Muradian, M. T. Sancho, A. Pascual-Mate, (2018) Journal of Apicultural Research, 57, 5-37.
 P. Fanjul-Bolado, M. B. González-García, A. Costa-García (2006) Analytical and Bioanalytical Chemistry, 385, 1202–1208.
Horsemint (Mentha longifolia (L.) L.) is a widespread wild-growing species in Hungary, but no up-to-date industrial application has been reported until now.
This work is the first evaluation of extractability of horsemint performed on a larger number of samples from Central Europe. Beside chemotaxonomical investigations, our goal is the selection of polyphenol-rich populations for cultivation as source of antioxidants.
Thirty-six spontaneous populations from Northern Hungary were sampled. Soxhlet and ultrasonic extractions were performed with methanol (MeOH) and ethanol:water 7:3 (WA). Antiradical activity was checked by DPPH and reducing ability by FRAP assay. Total polyphenol content (TPC) by Folin-Ciocalteu method.
The TPC of samples depend on the solvent and also on the METHOD: MeOH extracts produced higher values by the UH method while WA extracts gave higher values by Soxhlet. MeOH Soxhlet extracts reached 33243 mg GAE/kg d.w as a mean, while WA extracts showed 50-52000 mg GAE/kg d.w.
Against DPPH, extracts are stronger than carvacrol (EC50 =1776 mg/l), weaker than BHT (EC50=87.36 mg/l). Approx. 40% of samples exhibit EC50=150-320 mg/l from WA extracts, similar to data obtained from cultivated Mentha taxa . FRAP results show medium activity, reaching the value of BHT (12169 mg AAE/kg) only in some cases. Both DPPH and FRAP values obtained with WA ultrasonic extracts are better than the other methods.
Large variability (CV>20%) of the investigated parameters may refer to high diversity in polyphenol profile of samples.
Acknowledgments: The research was supported by EFOP-3.6.1-16-2016-00001‚ Complex improvement of research capacities and services at Eszterhazy Karoly University’
The authors gratefully acknowledge the valuable support of Bükk National Park in this project.
 H. J. Damien Dorman, M. Koşar, K. Kahlos, Y. Holm, R. Hiltunen (2003) Journal of Food and Agricultural Chemistry, 51, 4563.
Ponceau 4R (E-124) and tartracine (E-102) are synthetic azo colorants widely employed for imparting appealing color in many foods such as drinks and sweets. However, due to some adverse health effects related to migraines, anxiety an even mutagenic action and carcinogenicity, their employment must be strictely controlled. According to the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) the maximum daily intake of ponceau 4R (P4R) and tartracine (TR) are 4 mg/Kg and 7,5 mg/kg, respectively. Accordingly, in order to guarantee the consumers safety and respect the published regulations, accurate and reliable methods for the determination of these dyes are required. Widely employed methodologies are spectrophotometry, liquid chromatography and capillary electrophoresis but they are demanding in equipment and technical expertise. In contrast, electrochemical techniques are affordable and convenience for in-situ measurements.
In this work, we develop an electrochemical sensor for the simultaneous determination of both dyes in non-alcoholic beverages. The sensor, based on the modification of a glassy carbon electrode with two nanomaterials, WS₂ and diamond nanoparticles (GC/WS₂/DNPs), gives rise to an enhancement in the response with respect to both the bare GC and the sensor containing only one of the nanostructures, DNP or WS₂. This response consists in a pair of well-resolved peaks corresponding to P4R (+0.69 V) and TR (+0.95 V) and a redox peak at around +0.2 V, coming from both dyes. After optimizing the initial potential in DPV measurements, we found that if -0.3 V are applied to begin the scan, the only compound that shows the peak at 0.2 V is P4R. From a point of view of minimizing interferences, this latter peak, due to its low potential value, is more adequate to carry out the determination of P4R instead of that a higher potential.
Combining the synergistic effect between both nanomaterials for obtaining electrochemical sensors with improved sensitivities, with the adequate conditions for determining P4R at low potential for enhancing selectivity, the proposed methodology allows the simultaneous determination of both dyes with adequate analytical properties.
Phenolic compounds in their structure provide to appear in different colors of plants. They contained in plants are important substances due to their antioxidative and antimicrobial effects. The color also plays an important role in the attractiveness of food. Therefore, the colorants and their analyzes which constitute a group of food additives are of great importance. In the literature, in vivo and in vitro analytical techniques are developed for the analysis of pigments in plant materials.
In this study, it was aimed to make the total anthocyanin analysis of small amount of natural cherry samples with fiber optic reflection spectrophotometer. In addition, a sample preparation method has been developed in order to analyze the unstable anthocyanin pigments without any degradation in storage and measurement processes. In the developed method, extracted cherry samples were immobilized on chromatography paper and then reflection spectra were taken. The reflection measurements were successfully carried out since the chromatography paper was a smooth surface. It was also found that the samples impregnated on paper were not degradation for 15 days. Cyanidine 3-sophoroside chloride solutions (80 % methyl alcohol-HCl solution) were used for calibration. 11 different cherry samples which were collected from different regions of Turkey were analyzed by using the calibration graph. The total amount of anthocyanin in the samples was found to be between 1,56 and 10,12 mg / g in Cyanidine 3-sophoroside chloride equivalent. The results of the cherry samples were compared with the values obtained by spectrophotometric method and the difference between the results was not significant (p> 0.05).
Copper nanoparticles (CuNPs) have been synthesized and deposited on the surface of glassy carbon electrodes (GCE) to develop electrochemical sensors based on nanomaterials for sulfite detection. Two different CuNPs synthesis strategies have been employed: i) electrodeposition using copper chloride as a precursor; ii) physical evaporation using gas phase aggregation sources .
The morphological characterization by atomic force microscopy of the sensor obtained by CuNPs electrodeposition reveals a compact thin nanoparticle layer on the modified electrode surfaces, with typical measured dimensions of 10-22 nm in width (figure A). It should be noted that tip convolution effects enlarge the measured dimensions. On the other hand, sensors platforms based on CuNPs obtained from physical methods display an even more compact layer (figure B).
For the electrochemical characterization of the developed sensors, cyclic voltammetry is used as electrochemical technique and sulfite anion as an analyte in solution. The results obtained show that in all cases, considering the peak of oxidation and a given sulfite concentration, there is an increase in the analytical signal obtained with the CuNPs modified electrodes compared with the respective unmodified ones, which will allow to detect smaller concentrations of sulfite (as example, see figure C displaying results concerning the system with electrodeposited CuNPs). On the other hand, a decrease in the peak potential is observed, which will make it possible to avoid interferences from other substances present in the solution that could become also oxidized. The analytical parameters were obtained and compared for the different systems, obtaining better sensitives for sensors based on CuNPs from vapor phase. The developed analytical methodology is applied to the detection and quantification of sulfite in minced meat.
 L. Martinez et al. Scientific Reports 8 (2018), 7250
Reactive oxygen species (ROS) and nitrogen species (RNS) are continuously produced in the cellular system and are controlled by several antioxidants mechanisms. Reactive nitrogen species (RNS) take part in cell signalling under various physiological conditions and also provide host defense against bacterial and fungal pathogens (Kumar et al., 2013). While neither • NO nor O 2 •− are strong oxidants, ONOO − is highly reactive. They can cause damage to proteins, DNA, and lipids contributing to diseases ranging from atherosclerosis and aging to neurogenerative disorders such as Parkinson’s and Alzheimer’s disease (Dowding et al., 2012). Sodium
nitroprusside is stable in a dry environment, but it produces nitric oxide radicals in aqueous solution at physiological pH. Nitric oxide radicals are scavenged in the presence of antioxidant materials, and the excess of this radical is converted into nitrite by molecular oxygen (Ignarro et al., 1993). A novel nanomaterial-based colorimetric method was developed for sensitive and selective determination of nitrite by our laboratory. A literature searches reveals that there is no useful gold nanoparticles-based method for measuring either • NO or its scavengers. In the developed method, some parameters were optimized such as temperature, solvent medium, sodium nitroprusside concentration and reaction time. Before being scavenged with thiol type antioxidants, the nitric oxide blank absorbance (according to the proposed nano-colorimetric method) of the reference solution was stabilized at A ~ 1.100 after optimization of reaction parameters. The developed method was carried out between 7.27×10 -5 – 3.64×10 -4 mol L -1 final concentration range for L-cysteine, N-acetyl-L-cysteine, and cysteamine. As a result, nitric oxide radical scavenging activity of L-cysteine was found higher than N-acetyl-L-cysteine, and cysteamine.
Keywords: thiol-type antioxidants, nitric oxide radical, modified gold nanoparticles
This study was funded by Istanbul University-Cerrahpasa with the project number 23774.
Dowding, J. M., Dosani, T., Kumar, A., Seal, S., & Self, W. T. (2012). Cerium oxide nanoparticles scavenge nitric oxide radical
(˙NO). Chemical Communications, 48(40), 4896. doi:10.1039/c2cc30485f
Ignarro, L. J., Fukuto, J. M., Griscavage, J. M., Rogers, N. E., & Byrns, R. E. (1993). Oxidation of nitric oxide in aqueous
solution to nitrite but not nitrate: Comparison with enzymatically formed nitric oxide from L-arginine. Proceedings of the
National Academy of Sciences, 90(17), 8103-8107. doi:10.1073/pnas.90.17.8103
Kumar, S., Rhim, W., Lim, D., & Nam, J. (2013). Glutathione Dimerization-Based Plasmonic Nanoswitch for Biodetection of
Reactive Oxygen and Nitrogen Species. ACS Nano, 7(3), 2221-2230. doi:10.1021/nn305250p
For determination of semi-volatile components in wine samples was used HSSPME and vacuum-assisted HSSPME methods forward to compare the results of analysis. Focal point of this study was non-volatile additives in wine, such as sorbic acid, benzoic acid, polypropylene glycol. In sample preparation procedure wine samples were transferred into vials and evaporated up to removing volatile components, after these samples were equilibrated by freezing. Subsequently, equilibrated sample with air-evacuation step and without this technique analyzed by HSSPME and vacuum-assisted HSSPME methods following by parameters in gas chromatography mass-spectrometry equipment. Comparison of extracted semi-volatile constituents between two methods confirmed the hypothesis. Extracted benzoic acid, sorbic acid and polypropylene glycol by vacuum-assisted HSSPME method presented less extraction time and higher extraction capability than HSSPME. In this study for the first time, screening and quantitative possibilities of vacuum-assisted HSSPME method for the determination of semi-volatile components in wine have been evaluated.
Biogenic amines (BAs) are compounds generated by the enzymatic decarboxylation of amino acids (AAs). Common determination of both types of analytes is difficult, but interesting to obtain information about nutritional and hygienic quality , as BAs are an important quality index (high concentrations may indicate the presence of unwanted microbiological contamination or lack of cleanliness in food processing) [2, 3]. Furthermore, high concentrations of BAs can lead to toxicological problems, and some of them can produce negative effects on sensory quality of foods, giving them putrefaction or rotting flesh flavour .
Several factors affect the content of BAs in wine, among them the yeast strain and the amino acid composition of the must. A few studies have been conducted on the formation of BAs by yeasts quantifying only histamine [4-6] and influence of yeasts strain on BAs formation and AAs consummation on rosé wine made from garnacha  or Chardonnay white wine .
In the present research, the concentrations of 8 BAs and 9 precursor AAs have been determined in samples of sparkling rosé wine obtained from different yeasts (Saccharomyces cerevisiae and Torulaspora) and strains. The analytical method used combines online and automatic derivatization of analytes with their determination by UHPLC-FD .
The authors are grateful to the Ministerio de Economía y Competitividad of Spain (Project CTQ2017-82496-P) and the Junta de Extremadura (GR18-Research Group FQM003 and Project IB16058), both co-financed by the European Funds for Regional Development, for financially supporting this work.
 G. Fiechter, G. Sivec, H.K. Mayer. J. Chromatogr. B Anal. Technol. Biomed. Life Sci. 927 (2013) 191–200.
 S. Sentellas, O. Núñez, J. Saurina. J. Agric. Food Chem. 64 (2016) 7667–7678.
 M.V. Moreno-Arribas, C. Polo. Wine Chemistry and Biochemistry. Springer. New York (2008)
 Lafon-Lafourcade, S., Connais. Vigne Vin 1975, 9, 103-105.
 Somavilla, C.; Bravo, F.; Íñ] igo, B.; Burdaspal, P., Alimentaria 1986, 23, 37-42.
 Bravo, F.; Garcı´a, M. E., Alimentaria 1987, 24, 103-108.
 Torrea, D.; Ancín, C. Influence of yeast strain on biogenic amines content in wines: relationship with the utilization of amino acids during fermentation. Am. J. Enol. Vitic. 2001, 52 (3), 185-190.
 Torrea, D.; Ancín, C..J. Agric. Food Chem. 2002, 50, 4895-4899
Royal Jelly (RJ) is a natural product secreted by the hypopharyngeal and mandibular glands of worker bees. RJ contains many components such as water, sugars, amino acids, proteins, fatty acids and vitamins . Nevertheless, there is no international regulation concerning RJ harvest, production. Because of the poor storage conditions, royal jelly may be spoiled or lose its health-promoting properties . These changes occur due to the Maillard Reaction (MR). It is crucial to detect the MR from the early stages and furosine is commonly chosen as freshness indicator. Furosine is commonly quantified by liquid chromatography with UV detection. A purification step by SPE (Solid Phase Extraction) is usually conducted and long elution and acid hydrolysis times are general. Our main purpose was to develop a sensitive, rapid method using cation exchange seperation that is coupled with UV detection (HPCE-UV). The novel method has been applied to the analysis of 10 Turkish RJ.
RJ sample corresponding to about 30–70 mg of protein, was hydrolyzed with 20 mL of HCl 8N at 110◦C for 4h. The solution was filtered through 0.45 um syringe filter. We have to note that a purification of the hydrolyzate by SPE is indispensable to decrease matrix interferences for the usual determination of furosine. Here it is not necessary as the chromatographic conditions were specific to furosine. The HPLC analysis was carried out on an Thermo Accela UHPLC-UV system. The analytical separation was performed on a Grace Spec Furo column maintained at 40 ◦C. The flow was 1,2 mL/min and 10 uL sample were injected. The mobile phases were composed of 4% acetic acid and 0.34% KCl. The total run time was about 24 min.
To assess the linearity, working standard solutions of 5, 10, 20, 50, 100 and 200 ppm of furosine were injected in eight replicates. Calibration curves gave good fits (R2> 0.99). The LOD and LOQ were determined at 0,5 ppm and 1 ppm, respectively. The percent recovery was calculated it is found with 93% rate. To investigate the repeatability, 8 replicates of 3 calibration concentrations (5,20,50 ppm) were injected. The repeatability obtained were lower than 8%. After hydrolysis, the LC–UV method allowed analyzing a sample within 24 min. without further purification of the sample onto SPE cartridge. The furosine contents quantified just after harvest varied from 15.8 to 25,8 mg/100 g protein (mean value= 20.1 mg/100 g protein) for Turkish production. These values are in agreement with the literature.
HPCE-UV method was developed and it is more sensitive and rapid as compared to the common HPLC-UV methods and avoids cost and time intensive SPE purification step and shortened the time-consuming acid hydrolysis step (from 20-24 to 4 hour). Determination of furosine content in RJ by HPCE-UV was validated and 10 RJ samples were analyzed. So, furosine was a sensitive and efficient marker of the RJ degradation caused by the Maillard reaction during storage and it can be easly quantified using low cost and effective novel HPCE-UV methodology.
In this study, a novel online RP-HPLC method combined with post-column detection using CUPRAC (cupric reducing antioxidant capacity) methodology was developed, enabling a sensitive, selective and simple measurement of authentication markers (including tocopherol isomers) related to the authentication of a wide range of commercial and traditional argan oils. The components were reacted with chromogenic CUPRAC reagent in a reactor coil within one minute after HPLC separation. The proposed online assay was validated with good precision, reproducibility and linearity. Simultaneous analysis of argan oil, including quantitative analysis of tocopherol isoforms, total tocopherol content and antioxidant capacity determination without pre-treatment were carried out within 20 minutes. Sixteen argan oil samples (100% pure-certified and other commercial samples of argan oil), possible adulterating vegetable oils (i.e. olive oil, sunflower oil, hazelnut oil, soya oil, cotton seed oil and almond oil) and synthetically adulterated 100% pure certified argan oil blended with olive, sunflower, corn and soya oils at levels of 5%, 10%, 15% and 20% were analyzed. Spectrophotometric CUPRAC, DPPH and ABTS assays were also applied and TAC values measured as µmol/g trolox equivalent. Discrimination of adulterated argan oils from virgin samples was performed by utilizing chemometric orthogonal partial least square discriminant analysis (OPLS-DA) modelling with good sensitivity and specificity. We suggested [gamma-toc/alpha-toc] value as a new first screening adulteration factor that could be used to assess fraudulent argan oil samples, The distinct decrement in AF value was observed by the increase of adulteration rate. The AF values for virgin argan oils ranged from 11.8 (lower limit) to 18.6 (upper limit). The presence of β-sitosterol detected in commercial argan oils (with AF values out of limit values) was evaluated as fraudulent which was in accordance with the proposed assay. Our method enabled the detection of argan oil samples at adulteration levels of >5% in the case of sunflower, olive and soya oils, >15% in the case of corn oil. This method may be an alternative and specific assay for the authentication and quality detection of commercial argan oils.
This study was funded by Scientific Research Projects Coordination Unit of Istanbul University. Project number:58066. The authors extend their thanks to Istanbul University-Cerrahpasa Application & Research Center for the Measurement of Food Antioxidants (IUC-GAAM) for sharing its research infrastructures.
Pethidine (Meperidine, Dolantine) is a class of synthetic agonists of the opioid drug group. Opioids have strong depressive effects on the central nervous system, except for their strong analgesic effects. In particular, pethidine-containing drugs abuse is frequently encountered on health workers and patients. Pethidine is intensively hydrolyzed to norpethidine and excreted from the kidney. Therefore, it is important to determine the amount of norpethidine in the urine.
In literature, there is no analysis method for simultaneous determination of pethidine and norpethidine in urine. A new method was developed for the simultaneous quantitative analysis of pethidine and norpethidine. The method was validated according to the European Medicines Agency-Guideline on bioanalytical method validation parameters. The method was linear in the range of 9.00 - 1800.00 ng/mL. The developed and validated method was successfully applied for the determination of both analytes in real samples.
Buprenorphine is quite common on the illicit market. Buprenorphine is hydrolyzed to norbuprenorphine and excreted from the kidney. Therefore, it is important to determine the amount of norbuprenorphine in the urine for forensic.
Therefore a new method was developed for the simultaneous quantitative analysis of buprenorphine and norbuprenorphine. The method was validated according to the European Medicines Agency-Guideline on bioanalytical method validation parameters. The method was linear in the range of 9.00 - 1800.00 ng/mL. The developed and validated method was successfully applied for the determination of both analytes in real samples.
The popularity of oral fluid (OF), as alternative biological matrix for drug abuse testing, is increasing considerably in the last years. Oral fluid consists of saliva, gingival crevicular fluid, cellular de-bris, and other substances that are present in the oral cavity. There are several evident advantages of OF sampling compared to traditional matrixes such as very simple collection procedure without the need for special medical expertise, non-invasiveness, and lower potential for adulteration compared to urine . Taking into account the trace concentration of analytes of interest in oral fluid samples, selective and sensitive analytical methods are needed for reliable and accurate measurements.
In present research high performance liquid chromatography coupled with fluorescence detector (HPLC – FD) method has been developed and validated for screening 7 of the most commonly abused drugs and their metabolites in Estonia – amphetamine (AMP), methamphetamine (METH), 3,4-methylenedioxymethamphetamine (MDMA), 3,4-methylenedioxeamphetamine (MDA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), cocaine (COC), cocaethylene (COET). The chromatographic separation of all analytes was successfully achieved using Agilent Poroshell 120 EC-C18 column (100 mm × 4.6 mm i.d, particle size 2.7 µm.) and gradient elution. Detector parameters were set at excitation and emission wavelengths of 210 and 285 nm for AMP and METH as well as 230 and 315 nm for the rest analytes. Validation step included linearity, sensitivity, precision, accuracy, recovery, matrix effects and stability.
Additionally, five different oral fluid collection devices were evaluated based on their suitability for effective analyte collection and extraction for following chromatographic analysis. The devices under study were StatSure Saliva∙Sampler TM, Oasis Diagnostics® Super∙Sal TM, OraSure Intercept i2 Oral Fluid Collection Device, Sarstedt Salivette as well as Dräger DrugTest® 5000. Analyte recovery was evaluated by careful loading of 1 mL (or 0.4 mL for Dräger) of spiked saliva sample on the collection pad. The collecting and extraction procedures were adapted to obtained the highest recovery efficiency. After optimization the recovery of the analyte was >90% in most cases.
 Valen A, Leere Øiestad ÅM, Strand DH, Skari R, Berg T, Determination of 21 drugs in oral fluid using fully automated supported liquid extraction and UHPLC-MS/MS. Drug Test. Analysis 2016,9, 808–823
The Estonian Research Council (Institutional Research Fund No. 33-20. The project is co-financed by the European Union through the Internal Security Fund and by the Ministry of the Interior of the Republic of Estonia.
Various colors of glass beads excavated at Khlong Thom archaeological site in southern Thailand were characterized non-destructively using proton induced X-ray emission spectroscopy (PIXE), scanning electron microscope coupled with energy dispersive X-ray spectrometer (SEM-EDS), and Raman spectroscopy in order to determine the glass composition and production technology in ancient time. The results show that most of them are alkali-based glass matrix. Some of them are high lead-bearing glass. The glass compositions are approximately the same as Mediterranean, Islamic, and Indian glasses but with higher concentration of aluminum. The colors are influenced by transition metal-ions content such as copper, iron, and manganese. High content of lead has been found in the samples with opaque color, especially the yellow opaque. The corroded and flaked surface of glass bead has been revealed by SEM. In comparison of glass composition, it can be proposed that there are some relationship in production technology between Khlong Thom archaeological site and other sites: South-East Asia; South Asia; East Asia; Asia Minor; and South Africa. This information indicates the historical link of both land and maritime networks for long distance trade and exchange in ancient time.
Biofilm structures are the most resistant form of active microorganisms against sanitation, disinfection and sterilization processes. Enterococcus faecalis is an important global cause of nosocomial infections. Many nosocomial infections results from the ability of this bacterium to form biofilm. In this study, the antimicrobial activity of nisin bacteriocin alone or in combination with CHX, NaOCl and EDTA against planktonic and biofilm cultures of four strains of Enterococcus faecalis was investigated.
In order to determine MIC and MBC values of CHX, EDTA, NaOCl and nisin, the method described by Tong et al. (2011) was used. Then the Time-kill kinetics assay was performed to study the activity of the antimicrobial agents against Enterococcus faecalis strain and the bactericidal or bacteriostatic activity of test agents was determined over time. Synergic effect of the test antimicrobials was evaluated by checkerboard testing method (Odds, 2003). Following the investigation of biofilm eradication concentrations of agents via MBEC test (Extremina et al. 2011), their impact on biofilm structure was visualized via SEM.
According to the MIC values minimum concentrations of antimicrobials were effective against the bacterial cells. In the Time-Kill study, nisin was effective against cells only after 6h of incubation time. In the Checkerboard assay, a positive additive effect was found between nisin, EDTA and NaOCl, but against some strains of E. faecalis, there was an antagonistic effect between nisin and CHX. In MBEC assay, NaOCl and EDTA were the most effective irrigants against E. faecalis biofilms. Scanning electron microscopy showed that, the damage to E. faecalis biofilm with the combined nisin and EDTA treatment was the most effective among all of the different combined antimicrobial treatments.
As a result of our study, it was shown that nisin and EDTA combination is a good tool to combat with biofilm structure. To the best of our knowedge, there is no any research in the literature on the potential usage of nisin to inhibit biofilm formation and mature biofilm eradication of E. faecalis. Thus, the project is original both scientifically and technologically and also has widespread common potential.
This work was supported by the Scientific and Technical Research Council of Turkey (TUBITAK) under Grant No. 114Z668
In this study, we investigated the marT gene-related regulation characteristics of 15 different genes having different functions in biofilm formation and pathogenesis in Salmonella by using S. Typhimurium 14028 and its marT-disrupted derivative strain, MZ1627. Single-gene knockout mutants of csgA, csgD, ompC, fimA, fimD, fimF, fimH, fliZ, stjB, stjC, marT, rmbA, sthB, sthE, yaiC genes performed using wild type S. Typhimurium 14028, via insertion of antibiotic resistance gene into the target gene. In order to determine the role of marT on transcription of target genes, expression level of genes were assessed by real-time PCR using gene specific primers.
As a result of the data obtained from the qRT-PCR trials, the marT gene was determined to be the regulator of 14 genes, namely fimA, fimD, fimF, fimH, stjB, stjC, csgA, csgD, ompC, sthB, sthE, rmbA, fliZ and yaiC. QRT-PCR studies were also showed that the protein encoded by the marT gene is an autoregulator positively regulating its own promoter. All these data strongly suggested that the MarT protein does not only regulate misL gene expression, but it rather acts as a global regulator in Salmonella.
The term sulfite is used to describe tetravalent sulfur-based materials such as sulfites, sulfur dioxides, bisulfites, and metabisulfites, which are commonly used in a variety of foods and beverages. Sulfite, which is a protective agent in various food industries, also is known as an allergen. Therefore, sulfite content in food must be monitored and controlled. In this context, a novel optical sensor is designed for simple, rapid and sensitive determination of the sulfite content in food samples. Based on the usage of pararosaniline (PRA) method of sulfite determination, we developed an optical sensor applicable to the determination of sulfite content of complex samples. Acidified PRA hydrochloride reagent in cationic form was immobilized on the surface of the solid membrane. In formaldehyde medium, the pale purple PRA-solid film was converted to rich purple due to the highly conjugated alkyl amino sulfonic acid formation in the presence of sulfite and the absorbance change at 588 nm was recorded. The proposed optical sensor gave a linear response in a wide concentration range for sulfite. The limit of detection (LOD) and the limit of quantification (LOQ) values obtained for sulfite were 0.084 and 0.280 ppm SO₂ equivalent, respectively. The proposed optical sensor was validated in terms of linearity, additivity, precision and recovery parameters. The sulfite contents obtained for real food extracts were found to be comparable to the conventional iodometric titration results. The proposed optical sensor is insensitive to positive interferences from turbidity and colored components of the sample. Sulfite determination in a complex food matrix can be performed using the rapid, simple and sensitive PRA-based sensor without a need for pre-treatment.
In the past years, a great level of attention focused on herbs and spices as sources of antioxidants. The antioxidant properties are caused by the presence of compounds from different classes, such as vitamins, flavonoids, terpenes, carotenoids and phytoestrogens, which enable the use of spices as food preservatives. Natural antioxidants in spices are particularly attractive because they do not possess high toxicity .
Among the various natural antioxidants, phenolic compounds are reported to be active, quenching oxygen-derived free radicals by donating hydrogen atom or an electron to the free radical. Recent studies point to the capability of plant extracts (black pepper) to have similar patterns of phenolic compounds and their antioxidant activity was attributed mainly to their active principle, piperine .
Piperine, a naturally occurring alkaloid extracted from piper nigrum, has numerous demonstrated health effects and beneficial therapeutic properties which are systematically reviewed . The antiinflammatory effect of piperine has been demonstrated in in vitro experiments, showing to protect against oxidative damage by inhibiting or quenching free radicals and reactive oxygen species and hydroxyl radicals . The reported studies based on in vitro experiments point out that piperine has become one of potential candidates of antioxidants, but little attention has been paid to its chemical or electrochemical oxidation mechanism.
This study presents the electrochemical investigation of piperine using voltammetric techniques and different conditions to fully understand its oxidation mechanism. Electrochemistry is particularly useful to characterize the reducing potency of a compound, and controlled-potential techniques, such as cyclic voltammetry is commonly applied to rapidly assess the possible antioxidant activity.
The redox behaviour of piperine was compared to that of chosen model (reference) antioxidants: ascorbic acid, protocatechuic acid, syringic acid and tyrosine, given their ability to engender great electro-oxidation current.
The potential antioxidant properties of piperine were investigated by using different in vitro peroxidation models assays: (i) 2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO) scavenging; (ii) 1,1-diphenyl-2-picryl-hydrazylfree radical (DPPH) scavenging; (iii) ferric ions (Fe3+) reducing power; (iv) hydrogen peroxide (H2O2) scavenging.
Romanian National Authority for Scientific Research and Innovation, CNCS/CCCDI – UEFISCDI, project number PN-III-P3-3.6-H2020-2016-0011.
 L. Calucci, C. Pinzono, M. Zandomeneghi, A. Capocchi, S. Ghiringhelli, F. Saviozzi, S. Tozzi, L. Galleschi, J. Agric. Food Chem. 51 (2003) 927.
 R.S. Vijayakumar, D. Surya, N. Nalini, Antioxidant efficacy of black pepper (Piper nigrum L.) and piperine in rats with high fat diet induced oxidative stress, Redox Rep. 9 (2004) 105-110.
 L. Gorgani, M. Mohammadi, G.D. Najafpour, M. Nikzad, Piperine - The Bioactive Compound of Black Pepper: From Isolation to Medicinal Formulations, Comprehensive Reviews in Food Science and Food Safety 16 (2017) 124-140
 R. Mittal, R.L. Gupta, In vitro antioxidant activity of piperine, Methods Find Exp Clin Pharmacol. 22 (2000) 271-274.
In the present study, a capillary electrophoresis method, with a native fluorescence detection for the quantification of three amphetamine derivatives, methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-methamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA) in an oral fluid is described. The reported CE method has made it possible to assess Ecstasy abuse in approximately 15 min, including a saliva sample collection, pretreatment procedures and capillary electrophoresis (CE) analysis. The proof of the principle that was demonstrated on a home-made lab scale instrument has had the potential to be easily translated onto a truly portable instrument for on-site measurements. The baseline CE separation of the three illegal drugs was achieved in 10 min, by applying an aqueous background electrolyte (BGE) that was composed of 40 mM phosphoric acid and 10 mM triethanolamine. The amphetamine derivatives were detected at their λex/λem maximum (280/326 nm) with LOD values of about 3 ng/mL for each amphetamine. The recovery of the compounds from the collection pad was about 40% of the LOQ concentrations and the inter-day precision was less than 6% for all of the analytes. The procedure was applied to a quantitation of oral fluid (OF) samples that were collected during the Baltic Weekend Music Festival that was held in Estonia.
This paper proposed three stochastic microsensors for the assay of four interleukins: IL-1β, IL-6, IL-12, IL-17 with importance for early diagnosis of diabetes. Three types of chitosan: chitosan I, chitosan II, and chitosan III were used to modify the diamond paste needed for the stochastic microsensors. The stochastic microsensors were able to perform a qualitative analysis of the four interleukins, followed by a quantitative analysis. The response characteristics, selectivity, and validation of the proposed microsensors will be shown. The utilization of these microsensors for screening tests of whole blood of asymptomatic patients as well as of patients with diabetes will open a new chapter in the research of diabetes, and will establish the role of these interleukins in early detection of diabetes.
Acknowledgements. The authors wish to thank the financial support provided by the national project PN-III-P4-ID-PCE-2016-0120.
The biosynthesis of normal sphingolipids is started on the initial step of serine-palmitoyl transferase(SPT) activation which uses pyridoxal phosphate as a cofactor. However, several cases of type 2 diabetes or the hereditary sensory and autonomic neuropathy type 1(HSAN1) were reported to produce unusual sphingolipid, 1-deoxysphingolipids which formed by an alternate substrate usage of the enzyme, SPT. To investigate a sensitive quantitation and functional studies for 1-deoxysphinganine, fluorogenic analysis was used and ortho-phthalaldehyde(OPA) derivatization method was developed. Pig Kidney Epithelial cells, LLC-PK1 cells and Human Keratinocyte cells, HaCaT were extracted to analyze 1-deoxysphinganine by high-performance liquid chromatography(HPLC) linked to fluorescent detection(FLD)(Ex.340nm, Em.455nm). The isocratic elution of 90% acetonitrile successfully separate 1-deoxysphinganine from other impurities for quantitative analysis. The 48 hr incubation of cells with L-alanine increased the contents of 1-deoxysphinganine in a dose dependent manner. A ceramide synthase inhibitor, fumonisin B1 highly accumulated 1-deoxysphinganine and sphinganine indicating these sphingolipids were turned out to corresponding ceramide structures. Fumonisin B1 is a mycotoxin that inhibits ceramide synthases and causes kidney and liver toxicity and other disease. We compared the amounts of 1-deoxysphinganine and sphinganine by adding alanine and serine at different concentrations along with Fumonisin B1. furthermore, We changed the environment of the medium for give the stress. however the condition which is time, concentration and capacity etc are same. The results were derived according to the degree of oxidation of the medium and in the 37 degree of CO2 incubator or room temperature of the lab and with diffent amount of Fetal Bovine Serum(1 and 10%) in the medium. Experiments have shown that the stress of the cell affects the amount of 1-deoxysphinganine, Now, we are investigating the optimal protocol of the analytical method for 1-deoxysphinganine and related sphingolipids in HPLC-FLD system for further precise studies.
This research was financially supported by the Ministry of Trade, Industry, and Energy (MOTIE), Korea, under the “Regional Specialized Industry Development Program” (P0002162) supervised by the Korea Institute for Advancement of Technology (KIAT).
Due to the abuse of antibiotics, the emergence of drug-resistant strains bacteria has become a challenge in hospitals in recent decades. Simultaneously drug-resistant Acinetobacter baumannii causes a high mortality rate also to beget a serious problem in hospitals especially in the intensive care unit (ICU) ward around the world. Therefore, we developed the photodynamic antimicrobial method against the pathogen. We used reduced graphene oxide rGO/Ag/Fe-TiO₂ and BiOCl / BiVO₄ as a photosensitizer, according to their surface plasmon resonance property shift its absorption to visible light. Forevermore, these composite materials were producing superoxide anion (O2-̇) radicals of reactive oxygen species (ROS), and hydroxyl radicals (HO•). They can inactivate drug-resistant A. baumannii. In this study, a visible light source was selected, combined with 0.1, 0.01, 0.001 mg/mL of the photosensitizer nanoparticle concentration mixed with imipenem-resistant A. baumannii, irradiated 1.8 W/cm², 5.4 W/cm², and 10.8 W/cm² energy blue light. We found that when the nanoparticle was used alone, it had little effect on A. baumannii inactivation, but the blue light could trigger the antibacterial ability of rGO/Ag/Fe-TiO₂ and BiOCl / BiVO₄ nanoparticles to A. baumannii. It is shown that combines visible light combine with nanoparticles that can effectively inhibit clinical resistance bacteria.
Sweeteners are functional food additives that impart sweetness in food. Artificial sweeteners are being used as sugar substitutes in considerable and increasing amounts in food and beverages, especially for those who are diabetic and/or obese. Sugar cannot simply be replaced by these type of intense sweetener because the question of bulk, quality, intensity of sweetness and physical characteristics. These sugars tend to have desirable sweetness but are not metabolized in the human body and therefore do not provide calorie intake. Heavy artificial sweetener use (>1680 mg per day) leads to an increased relative risk of 1.3 for bladder cancer in humans. Aspartame is a low calorie sweetener used to sweeten a variety of low and reduced calorie foods and beverages including low calorie tabletop sweetener as well as for use in gum, breakfast cereal and other dry products. Acesulfame—k is not metabolized in the human body, thus it provides no calories and does not influence potassium intake despite its potassium content. Cyclamate itself shows very low toxicity but is metabolized by the gut bacteria to cyclohexylamine which shows greater toxicity because of the nature of cyclamate metabolism.
Results obtained using three stochastic sensors based on matrice of nanodiamond powder (nDP) modified with solutions of α, β, and γ cyclodextrin 10-3 mol L-1, for the simultaneous determination of aspartame, acesulfame K and cyclamate will be discussed. The three sweeteners were reliable determined in biological fluids and food samples using the proposed stochastic sensors.
Acknowledgemen: The authors gratefully acknowledge the Romanian National Authority for Scientific Research, UEFISCDI for financial support, under grants, PN-III-P4-ID-PCE-2016-0050.
The theoretical investigation of the physico-chemical properties of pyrazolooxazine systems, which could exhibit anti-inflammatory activity, has been carried out using DFT/B3LYP calculations. Calculations are performed in the gas phase with the Gaussian09 programin order to determine and analyze the equilibrium geometries of the pyrazolooxazine derivatives.The stability of these compounds has been analyzed using natural bond orbital analyses NBO. The results of analysis frontier orbitals show that pyrazolooxazine-2-thiones, which have a HOMO-LUMO energy gap (2.961 eV) lower than that of pyrazolooxazine-2-ones (3.211 eV), are therefore the most reactive and they have a nucleophilic behavior.The structure activity-properties of a large series of derivatives were investigated using the results using the HyperChem 8.0.6 software considering the Lipinski’s “ rule of five”.
It has been found that these compounds should exhibit good cell plasma membrane permeability. The results showed that the most promising compound is that where a thiophen ring being attached to the nitrogen atom which has the highest LipE value of the dataset could be considered as a good candidate for biological testing.
Sphingomyelinases (SMases) hydrolyse sphingomyelin, releasing ceramide, and creating a cascade of bioactive lipids. These lipids include sphingosine and sphingosine-1-phosphate, all of which have a specific signalling capacity. Thus SMases are involved in lipid signaling processes that render it a key regulator of the cell's fate. The molecular details of the most studied acid Sphingomyelinase (ASM) like its localization during signaling and its interplay with other proteins; however appear to be very complex.
Different probes were designed to monitor and quantify the activity of the ASM enzyme either in vitro or within living cells by means of Förster resonance energy transfer (FRET) techniques with real time resolution. The target of the design was to combine both higher substrate recognition, better 2P excitabillity and Synthetic potential.
Concerning the substrate recognition we manged to synthesize a probe with a quaternary nitrogen center highly mimicking the natural sphingomyelin which we expect that it will not only Speed up the enzymatic cleavage but may also allow the recognition of the probe by the neutral sphingomyelinase enzyme or other species comparable enzymes.
For better 2P excitabillity, a bromocoumarin dye derivative with high 2PE crosssections σ2 was selected to be used as a FRET doner with NBD as acceptor. With a perfectly 2P excitable probe we plan to reduce phototoxicity and increase imaging depth through our future live cell/tissue experiments.
With those probes in hand we are looking forward to start abroad range of applications which do not include only the searching and optimization of SMases inhibitors but also studying the complex nature of SMases production and localization in addition to the related physiological disorders.
Mycotoxins are a problematic and toxic group of small organic molecules that are produced as secondary metabolites by several fungal species that colonise crops. With wide ranging structural diversity of mycotoxins, severe toxic effect caused by these molecules and their high chemical stability, the requirement for robust and effective detection methods is clear. The most relevant group of mycotoxins is that of aflatoxins, carcinogenic products belonging to the Flavus, Parasiticus and Nomius species of the genus Aspergillus; among these, aflatoxin B1 (AFB1) is a potent human carcinogen (first hazard class in accordance with the classification of the International Agency for Research on Cancer).
In this work, an electrochemical enzyme-linked oligonucleotide array to achieve simple and rapid multidetection of aflatoxin B1 (AFB1) is presented. The assay is based on a competitive format and disposable screen-printed cells (SPCs). Firstly, the electrodeposition of poly(aniline-anthranilic acid) copolymer (PANI-PAA) on graphite screen-printed working electrodes was performed by means of cyclic voltammetry (CV). Aflatoxin B1 conjugated with bovine serum albumin (AFB1-BSA) was then immobilized by covalent binding on PANI-PAA copolymer. After performing the affinity reaction between AFB1 and the biotinylated DNA-aptamer (apt-BIO), the solution was dropped on the modified SPCs and the competition was carried out. The biotinylated complexes formed onto the sensor surface were coupled with a streptavidin-alkaline phosphatase conjugate. 1-naphthyl-phosphate was used as enzymatic substrate; the electroactive product was detected by differential pulse voltammetry (DPV). The response of the enzyme-linked oligonucleotide assay was signal-off, according to the competitive format. A dose-response curve was obtained between 0.1 ng mL-1 and 10 ng mL-1 with a limit of detection of 0.086 ng mL-1. Finally, preliminary experiments in maize flour samples spiked with AFB1 were also performed. From the obtained results, the developed analytical tool has proven itself to be applicable for screening field analysis.
Dopamine (DA) is one of the most important neurotransmitters present in the brain tissues and body fluids. Its change in the concentration levels has been associated to various mental diseases and disorders such as Alzheimer and Parkinson. Thus, there is a constant need in developing new sensing systems for the fast detection of dopamine neurotransmitter.
In the last couple of years, most of the work was devoted for synthesizing new sensing nanocomposites to improve a sensor performance in terms of sensitivity, selectivity, and biocompatibility. Of those synthesized nanomaterials, conducting polymers composites have been widely used in the construction of sensor surfaces. The synergy of multifunctional materials, recognition elements, and electrochemical methods is improving the selectivity, stability, and reproducibility, thus promoting the development of sensors for assays and bioassays. Graphite-based electrodes have been usually employed as working screen-printed electrodes and their modification with various nanomaterials, such as nanowires, nanoparticles, and carbon nanotubes, have been investigated for increasing the measurement sensitivity.
This work had as main objective the development of new platform based on graphite screen-printed electrodes for electrochemical sensing application. The electrode surface is modified with polyaniline and gold nanoparticles and the electrochemical characterization of the modified electrodes was studied in detail through cyclic voltammetry (CV) in the presence of the redox probe Fe(CN)63−/4−. The results showed the electrochemical processes at the electrode surface were controlled by diffusion of the electroactive species from the interior of the electrolyte solution to the electrode support.
Finally, the platform was applied for DA detection by differential pulse voltammetry (DPV).
A linear correlation was obtained in the range 5 – 100 µM of DA standard solutions, where the interference study was also performed to test its selectivity. The chemosensor showed good stability and reproducibility for multiple analyses and was further tested in real samples with a good recovery.
Parathyroid hormone (parathormone, PTH) is secreted by the chief cells of the parathyroid glands as a polypeptide which contains 84 amino acids. The changes in the PTH-level within serum can directly indicate the parathyroid gland disease. For example, hyperparathyroidism can result in excessive production of PTH. PTH can not only regulate calcium and phosphorous levels in extracellular fluids, but also stimulate the multiple intracellular signals of cyclic adenosine mono-phosphate (cAMP) and both protein kinases A and C. Moreover, the PTH level is also associated with cardiovascular and chronic kidney diseases, and several types of cancer . In this study, an ITO-PET (indium tin oxide- polyethylene terephthalate) based immunosensor system was developed for PTH detection. To detect the analytical characterization of 3-CPTMS (3-cyanopropyltrimethoxysilane) modified immunosensor, linear range, repeatability, reproducibility, regeneration studies were performed. Kramer's-Kronig transform was used to understand whether the impedance spectra of the biosensor system are affected from the variations that occurred because of the external factors. Kramer's-Kronig transform is a powerful tool to validate the impedance spectra . The interactions between anti-PTH antibody and PTH antigen were followed by Single frequency Impedance technique (SFI). The morphological images of the modified ITO-PET electrodes were observed with Scanning Electron Microscopy (SEM). Also, the shelf life of the developed biosensor was investigated. Finally, the real human serum samples were analysed with the constructed immunosensor for PTH detection. The results showed that the designed biosensor system presents high potential for medical use.
Permanent hair dyeing is a popular process adopted by millions of people around the world, and involves complex oxidative reactions between precursor agents (aromatic amines) and couplers (phenolic compounds), in oxidizing alkaline medium, inside the hair strand. The p-toluenediamine (PTD) has been increasingly used in permanent hair dye compositions as precursor agent and it is associated with many adverse effects, such as allergies, dermatitis, skin infections, eye irritation, opacity of the corneas, stomach ulcers, aplastic anemia, and it is recognized for its high genotoxic, mutagenic and carcinogenic properties.
However, little is known about the interaction mechanism of hair dyes with the capillary fiber. In this way, the investigation of the interaction of PTD with keratin is important since will enable in a better understanding of the physiological mechanisms of action and the side effects of hair dyes.
The evaluation of the keratin interaction with PTD in incubated solutions, by differential pulse voltammetry and ultraviolet-visible spectroscopy, and in situ using a keratin-electrochemical biosensor, was investigated. The effect of the keratin-PTD interaction was electrochemically followed comparing the changes in the queratin electroactive amino acid residues oxidation peaks, in the absence and presence of the PTD.
The interaction occurred in two ways. First, PTD interacts with keratin causing the condensation/aggregation of keratin, producing a rigid PTD-keratin complex structure, with a preferential interaction between the keratin amino acid residues carboxylic groups with PTD. Subsequently, the intercalation of PTD molecules in the keratin structure, cause greater exposure of the keratin amino acids residues at the GCE surface and, consequently, greater ease in oxidizing them. The peaks attributed to the keratin amino acid residues oxidation detected, suggest that, under the experimental conditions used, PTD induce keratin oxidative damage.
Acknowledgements: PhD Grants 2015/12998-1 and 2018/12449-6 (J. C. Souza) from FAPESP/Brazil are gratefully acknowledged.
In this work, we present a smartphone-based multiplexed enzymatic biosensor utilizing the unique colorimetric properties of the poly(aniline-co-anthranilic acid) (ANI-co-AA) composite film coupled with horseradish peroxidase (HRP), glucose oxidase (GOx), horseradish peroxidase-glucose oxidase (GOx-HRP) and tyrosinase (Tyr) enzymes. The enzymes are immobilized on the composite polymer film by adsorption and they catalyze a reversible redox color change of the host polymer from green to blue in the presence of their substrate. A smartphone was applied as color detector, for image acquisition and data handling. A ColorLab® android application, free of charge software application, was used to enable easy and clear display of the sensors’ response indicating remarkable changes in the optical features. The results were confirmed by the spectrophotometric measurements. The developed colorimetric enzymatic biosensors were studied and optimized in relation to different experimental parameters. Moreover, the colorimetric enzymatic biosensors were applied to food and pharmaceutical analysis. It has been shown by these studies that the colorimetric biosensors are promising as quick and simple tests for handheld analysis in various fields.
Heat shock proteins are defined as molecular chaperones and they play an important role in the cellular stress response including heat, toxicants, reactive oxygen species, injuries, diseases, and other stressors . One of the most important members of HSP familly is HSP70,its exist in all alive organisms. HSP70 is preventing protein aggregation and informs about increased tumor cells .
In this study, an ITO-PET (indium tin oxide polyethylene terephthalate ) based biosensor is configured to detect HSP-70. Then, coated with gold nanoparticles, ITO-PET electrode surfaces were modified thionin. Then, gluteraldehyde was used as crosslinker. The HSP-70 concentration, antiHSP-70 concentration and incubation time, HSP-70 incubation time were optimized. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were used for immobilization,optimization and analytical studies; Linear range, repeatability, reproducibility, regeneration studies were investigated to characterize the proposed biosensor. Kramer's-Kronig transform was used to understand whether the impedance spectra of the biosensor system are affected from the variations that occurred because of the external factors. The storage life of the biosensor was determined. Square wave voltammetry technique was applied to the biosensor. Single frequency technique was used to monitor the interaction between the anti-HSP-70 and HSP-70. Finally, the designed biosensor was applied to real human serum.
Cigarette butts are an important residual and peripheral environmental pollution threat because of primarily containing cellulose acetate. 5.8 trillion of cigarettes are smoked global per annum producing >800000 metric tons of cigarette butts.These butts contain many toxins, which cause leaking to ground and waterways, damaging living organisms that contact with them. The findings of this study reveal that hydrothermal carbonization (HTC) of cigarette butts generates porous carbons that have a high surface area (1012 m₂g⁻¹). Among the available techniques for obtaining porous carbon, hydrothermal carbonization provides promising features for various applications.HTC derived carbon material have chemical stability and porous structure with the consist of conjugated furanic skeleton.Carbon materials have recently been used in sensor design. The high conductivity of these carbon materials is ideal for the electrochemical signal transduction, while its high porosity can achieve adsorption of large molecules. Additionally heteroatom (N, S)doping into the carbon skeleton provides a useful way in order to adjust their physical and chemical properties such as the catalytic performance, electrical conductivity and sensing sensitivity. In this study, porous carbon obtained from HTC of butts was applied in an electroanalytical application.The effects of two important properties such as porosity and heteroatom, which affect electrical conductivity and surface area, have been investigated. Trandolapril is an angiotensin-converting enzyme inhibitor used to lower blood pressure. It could be easily absorbed and metabolized in liver indicating higher lipophilicity compared to other ACE inhibitors.The voltammetric behaviour of antihypertensive drug trandolapril (TRD) was investigated on glassy carbon electrode (GCE) that modified by cigarette butts derived char/Nitrogen doped carbon spheres (c-char/NCS).The electrooxidation of TRD using bare and modified glassy carbon electrode was investigated by differential pulse (DPV) and cyclic voltammetry (CV) (figure 1). The dependence of the current on pH, concentration and scan rate were investigated to optimize the experimental conditions for the sensitive quantification of TRD. The oxidation of TRD was exhibited a diffusion-controlled fashion at pH 3.0 phosphate buffer (PB) solution. The calibration curve was linear between the 8×10⁻⁸ and 8×10⁻⁵ M with the detection limit of (LOD) 1.09×10⁻¹° M by DPV in pH 3.0 PB solution. LOD was obtained as 2.57×10⁻⁸ M by DPV in pH 3.0 PB solution in presence of human serum sample. According to literature, there has no any study about TRD detection by voltammetry, so that this study will be first at this point. The oxidation mechanism was investigated in detailed with selected model drugs. The used method did not need to any separation, pretreatment steps or complex sample preparation. It is very easy and it can be considered for clinical application with portable devices in future to prevent long time analysis periods. To the best our knowledge, this is the first time a novel electrochemical sensor was developed for detecting drug TRD using various carbon structures produced from urea and cigarette butts.
The authors gratefully acknowledge the support of the Scientific Research Projects Coordination Unit (BAP) of Ankara University, Turkey (Project No: 18B0430007).
Therapeutic monoclonal antibodies (mAbs) play a crucial role in treatment of a variety of human diseases, such as inflammatory diseases, cancer and some autoimmune disorders in recent years. Monitoring their levels of individual patient is of great importance and could control patient-specific dose and improve therapeutic outcomes. However, because of the complexity of biological samples, the determination of mAbs concentration in serum is often fraught with difficulties.
In this study, a facile electrochemical impedance biosensor integrated with CD20 epitope mimic peptide recognition unit, and poly adenine (polyA) sequence as anti-fouling layer was fabricated to detect Rituximab (RIX) in serum. Cysteine-terminal affinity peptide (CN14) was preferentially anchored on the surface of gold electrode, and polyA was subsequently modified on it to block superfluous sites. The fixed peptides on electrode can specifically capture RIX, and a well-designed signal amplifier was introduced to enhance the sensitivity of biosensor. Results show that the optimized polyA sequence can not only effectively avoid the matrix interference, but also possesses lower background signal compared with the the traditional gold active sites blocking reagents such as bull serum albumin and 6-Mercapto-1-hexanol. Additionally, the secondary antibody mediated signal amplifier can gain about 5 fold signal amplification which is proper for the RIX detection in the complicated serum sample.
Express diagnostics of cancers is one of the most important tasks today. Monitoring of the tumor marker's levels, specific proteins expressed by cancer cells, simplifies the pre-symptomatic diagnosis of cancer, and also allows to evaluate the effectiveness of the therapy (Siegel et al., 2018). The development of the biosensors conception will greatly simplify and expedite the differential diagnosis, as well as make it available to people. Addressed covalent immobilization the receptor layer contributes to an improvement in the analytical characteristics of biosensors, an increase in the lifetime and miniaturization of the devices. One of the most widely used methods for electrode functionalization is aryl diazonium salts electrografting (Bouden, Pinson, & Vautrin-Ul, 2017). It is known the electroreduction of diazonium salts is accompanied by the irreversible transfer of one electron in the potential range of -0.2 - -0.6V with subsequent separation of molecular nitrogen and the formation of a covalently-immobilized functional monolayer on the electrode surface (Bélanger & Pinson, 2011). Excess aryl radicals formed in the near-electrode layer can react with an electrodeposited monolayer by intermolecular interaction, and also be kept on the electrode under the action of electrostatic forces. Such films are suitable for further bioconjugation, however, they block the transfer of electrons and therefore have a negative effect on the analytical characteristics of electrochemical immunosensors. The degree of blocking increases as the film grows. Changing the film thickness is carried out by electrografting parameters (potential, time, composition of the working solution), the use of radical traps or, more rarely, the synthesis of diazonium salts with non-benzene radical (Paloma Yáñez-Sedeño, Susana Campuzano, & José Pingarrón, 2018).
The aim of this research was to create a label-free electrochemical immunosensor for the determination of carcinoembryonic antigen (CEA) with an addressed-immobilized receptor layer by electrografting 3-carboxy-1,2,4-triazoldiazonium salt.
In the course of the study, the electrografting of 3-carboxy-1,2,4-triazoldiaonium chloride on a gold electrode was explored. The mechanism was proposed and the working conditions of electroreduction were chosen. The differences in the structure of the functional layer formed by electrografting of 4-carboxyphenyldiazonium and 3-carboxy-1,2,4-triazoldiaonium salts on a gold electrode were established. The immunoreceptor layer was immobilized by carbodiimide cross-linking onto the surface of the modified gold electrode. Under the selected operating parameters, the detection limit of the immunosensor was estimated as 0,1 ng/mL, the linear range was 10-1000 ng/mL.
|Electrografting of diazonium salts||CV from 0,7 to −0,8 V (scan rate of 50 mV/s) during 5 cycles|
|Carbodiimide binding of antibodies||Incubation in 100 mM NHS and 400 mM EDC for 20 min (PBS pH = 5,0)|
|Immunocomplex formation||Incubation during 40 min in antibodies and 80 min in CEA suspensions|
|Analytical signal detection||CV from -0,5 to 0,8V (scan rate of 100 mV/s) in the 10 mM K3[Fe(CN)6] / 10 mM K4[Fe (CN)6] and 1 M KCl|
The modification of graphite powder with copper oxides is presented by using a simple method. This work reports on the fabrication of sensitive and selective gas sensors fabricated using graphene and/or copper oxide (CuO). Graphite powder is impregnated with copper(II) nitrate by stirring the powder in copper(II) nitrate solution for 1 hour and subsequently thermally treated at 800K. The modified carbon powder was characterized using powder FTIR, XRD, UV/VIS, SEM/EDS and the existence of both copper(II) oxide have been ascertained by means of XPS. The electrochemical behavior of copper(II) oxide nanoparticles in alkaline media has been exploited to develop a sensitive electrochemical method for CuO as a gas sensor.
DNA nanobiosensors are significant in diagnostic tests for gene sequences analysis, gene mutation and cancer detection at early stages.. Among all biosensors electrochemical sensors were widely investigated particularly because of their high sensitivity and selectivity. With the advancement of Nanoscience and nanotechnology nanomaterials were also introduced to improve sensor design and its performance. A very sensitive DNA biosensor has been developed based on MWCNT-NH2 modified GCE. Gemicitabine Hydrochloride (GMB) is a synthetic pyrimidine nucleoside and is widely employed in standard treatment for pancreatic cancer, tumours of the bladder, breast, lung, renal cell carcinoma and biliary tract cancer. The developed nanobiosensor were employed to explore the interaction between Gemcitabine and dsDNA by differential pulse voltammetry. Also, electrochemical impedance spectroscopy studies was performed to compare of the modified electrodes. In order to define and visualize the interaction mechanism between GMB and dsDNA/NH2fMWCNTs/GCE at molecular level, in silico methods were exerted.
These interaction studies provide an opportunity to learn about the mechanisms of interaction and may be useful in designing new DNA target drugs.
Fourier Transform Infrared Imaging (FTIR imaging) and Multivariate Analysis were used to identify, at microscopic level, the presence of Florfenicol (FF), an antibiotic very used in salmon industry as therapy against several diseases affecting the salmon farming. Since FF is added to the feed pellets by surface-coating and considering that the distributional homogeneity of an active principle in a pharmaceutical formulation is very important to ensure its effectiveness, we studied how much FF penetrates evaluating its distribution from the surface to the center of the pellets. Hyperspectral images obtained with FTIR imaging system in attenuated total reflection mode (ATR) with pixel size of 6.25 μm × 6.25 μm in different zones of the feed pellets with FF concentration of 1.28 ± 0.004 mg FF/ g of pellet, were analyzed with partial least squares – discriminant analysis (PLS-DA). We described FF distribution in images obtained from the surface and at 100 µm and 150 µm of depth and we found absence of FF at 200 µm and 800 µm (center of the pellets), showing that FF remains close to the surface. Additionally, we assessed the homogeneity percentage (%H) of FF in the images in order to evaluate how FF is distributed in these zones with macropixel analysis and homogeneity curves 
Even the very low concentration of FF in the pellets, we demonstrated the powerful ability of the used spectroscopic technique and multivariate analysis to study this active principle into a complex matrix and at microscopic level, with results that allow monitoring the incorporation of the drug to the feed pellets.
 Neirivaldo Cavalcante da Silva et al. Chemometrics and Intelligent Laboratory Systems, 2018.
Direct measurement of human renin in plasma matrix is not applicable for determination by liquid chromatography coupled to mass spectrometer (LC-MS) due to its high molecular weight. Therefore, low abundant proteins like human renin require extended purification and digestion procedures prior to quantification of the unique signal peptide. In preliminary experiments the digestion procedure –as suggested by the kit supplier- resulted in insufficient chromatographical response. Due to the impact and linking of each factor on the digestion, a design of experiments (DoE) was selected to optimize the signature peptide response and to shorten the digestion procedure after enrichment with immobilized antibodies.
500 µL human plasma was used as matrix spiked with 20 ng human recombinant renin. Immunocapture was performed by anti-human renin antibodies immobilized and covalently coupled to Dynabeads Protein G. The unique signature peptide (VVFDTGSSNVWVPSSK) with the transition 854.9 m/z to 418.2296 m/z was optimized for determination by Sciex TripleTOF 6600 mass spectrometer. The optimization of digestion was addressed by a design of experiments (MODDE pro, v12.0). To optimize the signature peptide response: trypsin concentration (investigated range: 50-1000 ng), temperature (15-70 °C), vortexing speed (0-800 rpm), digestion time (6 minutes - 30 hours) and pre-digestion (0-4 hours) were investigated. D-optimal design was regarded as acceptable if the goodness of fit (R2) and the goodness of prediction (Q2) were above 0.5.
Since model’s goodness of fit and goodness of prediction were successfully proven (Q2: 0.916; R2: 0.950), the D-optimal response surface model was accepted for predicting optimal conditions. The digestion procedure were substantially optimized by identifying best settings for the impacting parameters. Increasing the trypsin concentration revealed the most influent parameter, which allowed for an increase of LC-MS response (75% increase by raising from 50 to 1000 ng trypsin). An additional improvement of 59% was achieved by performing the digestion at 15 °C instead of 70 °C. The impact of the vortexing speed (800 rpm) led to an increased up to 59% compared to absence of it. A sufficient digestion was achieved in the pre-digestion step at 2.5 hours, which led to the highest response (Figure 1). Subsequently, the duration of the process was shortened to only 2 ½ hours compared to conventional protocols which are performed over-night. Combining the optimal conditions (1000 ng trypsin, 15 °C, 800 rpm, 2.5 hours of pre-digestion and 0.19 hours of digestion) resulted in a predicted probability of failure of 0.1%.
This investigation led to a substantial shortening and improvement in signal intensity of the signature peptide response. The optimized digestion marks a crucial step towards a sensitive detection of endogenous renin by LC-MS.
In this study the capacity of the confocal laser scanning microscopy (CLSM) for the analysis of solid pharmaceutical tablets was evaluated in order to extend this application as a novel analytical technique of hiperespectral imaging. A multicomponent system of a solid dosage form composed by a mixture of acetominophen and caffeine (Active ingredients) and three exipients where at least one excipient fluoresce, were evaluated using this technique for qualitative and quantitative studies, supported by chemiometric analysis of emission spectra. Chemical mappings of synthetic tables (512 μm x 512 μm) were obtained using a spectral confocal Zeiss microscopy LSM780 and with a 405nm excitation laser. Principal component analysis (PCA) and multivariate curve resolution with alternating least squares (MCR-ALS) were applied on spectra for localization of fluorescent components (Figure 1). While partial least squares (PLS) was applied to obtain a calibration model to quantify caffeine, which was validated by cross validation and external validation to finally predict the caffeine concentration. A quantification per pixel of image was also archieved through multivariate image regression.
Results showed that CLSM has great advantages on other hyperspectral techniques in analysis of pharmaceutical tablets.With high resolution images obtained in a reduced time (less than 5 min). Besides, CLSM supported with multivariate analysis, allowed solving systems with a high level of overlap with the best results obtained by MCR-ALS. PLS models showed standard errors of prediction around (5-8% w/w) in external validation and high values of regression coefficients (r2) between predicted and expected values. This can demonstrate that CLSM is an image analysis technique and not only microscopy, it can be useful for quality control processes in the pharmaceutical industry where is required not only the localization but also the quantification of active fluorescent principles.
Acknowledgements: Fondecyt Regular Project 1191281.
Phenolic composition of food and beverages have been widely studied and received increased research intensity due to their nutritional benefits and biological activities.
Two untargeted fingerprinting techniques (UPLC–ESI–TOF/MS and UPLC-DAD) were comparatively investigated to assess their capability to classify ninety-five extra-virgin Argan oils (EVAO) with a protected geographical indication, according to their Moroccan geographical origins (‘AitBaha’, ‘Agadir’, ‘Essaouira’, ‘Tiznit’ and ‘Taroudant’). In a preliminary step each chromatogram was handled individually prior to the application of chemometric tools. Principal component analysis (PCA) was used as an exploratory technique to distinguish the five origins (groups) based on both sets of chromatographic data. Further, three multivariate pattern recognition techniques, i.e. Soft Independent Modeling of Class Analogies (SIMCA), Partial Least Squares Discriminant Analysis (PLS-DA), and support vector machine (SVM), were applied to classify the samples by both fingerprint types. The obtained classification models were highly sensitive and accurate. The predictiveness of the classification models was confirmed with an external data set and high recognition and prediction abilities were seen. Both the results from the UPLC-DAD platform and the UPLC-QTO/MS profiling were able to categorize the samples with high accuracy. Potential phenolic bio-markers responsible in the classification were identified and quantified using both platform techniques.
Metabolic fingerprinting approaches based on phenolic profiling were performed and demonstrated to provide useful data to classify the Argan-oil geographical origins.
Solid phase microextraction (SPME), is a sampling and sample preparation technique in which the extraction of analytes is based on an equilibrium established between a sample and extractive phase coated on a tip of a fiber. Thin film microextraction (TFME) which is a type of SPME provides high analytical sensitivity in environmental and biological samples and has gained interest in areas where no other technique can provide solutions. In this study, the aim was to develop biocompatible and flexible contact lens shaped thin film extractive membranes applicable to in vivo investigations with the ultimate goal of using them for small molecule sampling from eye surface. To make them suitable for sampling from the eye surface, the membranes are synthesized with polydimethylsiloxane (PDMS) using special templates. These extractive lenses are modified with various functional moieties to enhance their extraction coverage for polar and nonpolar analytes. Afterward, the membranes are tested for their extraction performances with in vitro test model. The small molecules (‹1500 Da) extracted from this model are separated by gas chromatography and liquid chromatography and detected by mass spectrometry (MS).
Tissue metabolomics brings a few challenges comparing to most common biofluid analysis. Firstly,
tissue sample is often non-homogenous. Moreover, sample preparation is more complex and includes more steps which have to be controlled to avoid bias and contamination. However,
while studying a disease, tissue is a matrix where specific biochemical changes can be directly
observed. In this study, we focused on gastrointestinal stromal tumour (GIST), which is a rare
type of cancer affecting around 15 people per million in Europe. Although genetic
backgroundof the disease has been extensively studied, metabolic patterns during GIST development
have not yet been investigated and elucidated.
To acquire knowledge about biochemical status of cancer tissue, we chose to apply untargeted
metabolomics with the use of LC-MS. The first stage of the study was focused on selecting the
most appropriate sample preparation method. Due to limited availability of GIST tissue samples,
we aimed at developing a method that provides possibility of extracting both polar and lipophilic
metabolites from one small GIST specimen. Tissue samples were homogenized with a 50:50
mixture (v/v) of methanol and water in ratio 1:10 (w/v) and obtained homogenate was subjected
to five different methods of extraction. They included monophasic extraction with methyl tert-
butyl ether (MTBE) and methanol, biphasic extraction with different ratios of MTBE, methanol
and water as well as with dichloromethane, methanol and water, and two-step extraction with the
same solvents. Organic extracts were analyzed with reversed phase LC-TOF-MS, while HILIC
separation was used for polar extracts. Sample preparation methods were assessed based on the
number of features detected in the extracts and reproducibility of extraction procedure.
The selected method will be further used in metabolomic fingerprinting of GIST tissue
specimens, which will be complementary to genomic studies on GIST. Metabolomic analysis of
GIST tissue may provide better insight into the disease or propose potential new therapeutic
Every year a large number of hospital-acquired infection cases are recorded in the world. There are several reasons for this: a decrease in the immunity of patients, the development of resistance of microorganism strain, an increase in the number of patients in medical institutions, including insufficient hygiene of medical staff hands.
Health care workers handle hands in two ways: hygienic hand washing with soap and water to remove contaminants and reduce the number of microorganisms, and treatment of hands with the skin antiseptic to reduce one to a safe level. However, a high level of hospital-acquired diseases shows a lack of quality of these procedures.
It is known that the level of hand hygiene is increased by increasing the availability of antiseptic or control procedures by the managing staff. The introduction of alternative forms of antiseptics (foam, gel) did not bring the desired results.
This work proposes the new control method for this procedure, which consists of the introduction of a marker substance into the composition of the skin antiseptic. The indicator will interact with the marker substance. To implement this method, the following requirements are imposed on the marker substance:
• no impact on the effectiveness of skin antiseptic
• no irritating effect
• connection availability
Dimethylglyoxime, also known as Lev Chugaev’s reagent, was chosen as a marker substance. As a result of the interaction of dimethylglyoxime with a nickel cation (Ni2+), a scarlet-colored bis-(dimethylglyoxime) nickel(II) chelate compound is formed.
The initial stage of the control procedure consists in the treatment of hands with a skin antiseptic containing dimethylglyoxime. This compound is not immediately absorbed into the skin, which makes possible to collect it from the surface of the hands with an alcohol moistened tampon. Since the transition metal salts are toxic, it is necessary to minimize contact of the containing nickel(II) solution with human hands. Therefore, a solution of nickel salt and sodium hydroxide solution is applied to a tampon. As a result of the interaction, the scarlet staining of the tampon can be observed. The appearance of a color spot indicates that the hands were treated with a skin antiseptic.
Further optimization revealed dependence between the intensity of stain and the time interval between the treatment of hands and the procedure of washing. Thus, it was found that the optimal time is less than an hour, as with its increase dimethylglyoxime can be completely absorbed into the skin, and the components of the antiseptic can contribute to the speed of this process.
However, the procedure for determining the influence of the main components of the skin antiseptics, such as alcohol, emulgators, quaternary ammonium compounds, polyhexanide hydrochloride, chlorhexidine digluconate, dyes, and perfumes, was not detected. To determine the condition of dimethylglyoxime in the composition of skin antiseptics spectroscopic and chromatographic methods were used.
During assess tests the effect of dimethylglyoxime on the toxicological properties of skin antiseptics with typical formulations were investigated. No negative influence was revealed in the study by in vivo and in vitro methods.
A disinfectant is defined as a product that is intended to kill harmfull organisms by chemical means. Today there is a wide variety of disinfectants. They have different formulations and different combinations of active sub-stances. However, among all formulations, cationic surfactants are more often used as active substances. The most widely used: quaternary ammonium com-pounds (QAC), guanidine derivatives and N,N-bis (3-aminopropyl) dodecylamine.
The are some methods for the determination of cationic surfactants involves a number of different problems arising from the specificity of sample matrix type and analytes (contaminants, low level of surfactants, chemical structure of active substances).
The aim of our research was the development and validation of a HPLC-based method for the simultaneous determination of benzalkonium chloride (ADBAC), alkyldimethyl(ethylbenzyl)ammonium chloride (ADEBAC), didecyldimethylammonium chloride (DDAC), chlorhexidine digluconate (CGBG), polyhexanide hydrochloride (PHMB), and N,N-bis (3-aminopropyl) dodecylamine (TA) in the disinfectants.
For the determination of ADBAC, ADEBAC, CGBG, and TA in the disinfectants a reverse phase high performance liquid chromatographybased method with a diode array detector was proposed. Chromatographic analysis was performed on the column Acclaim™ Surfactant, 5 μm 120Å (4.6 x 250mm). Experiment was carried out under gradient elution conditions at a flow rate of 1 mL / min. The mobile phase composition was a mixture of ace-tonitrile as eluent A and 0.1 M aqueous ammonium acetate acidified to pH 5.4 with acetic acid as eluent B. Determination of TA was carried out with preliminary derivatization of p-nitrobenzaldehyde.
Hydrophilic interaction chromatography (HILIC) is valuable alternative to reversed-phase liquid chromatography separations of polar, weakly acidic or basic samples. Thus a rapid and simple method for the determination of PHMB by HILIC with a diode array detector was developed. Best separation was achieved using of analytical column Phenomenex Luna NH2 (250×4.6 mm) with a particle size of 5 μm. The mobile phase composition was a mixture of acetonitrile as eluent A and 0.1 M aqueous ammonium acetate acidified to pH 5.4 with acetic acid as eluent B.
Because of DDAC does not absorb in visible and UV spectral regions, the diode array detector can’t be used for its analysis. In this work, the determination of DDAC was carried out by reverse phase high performance liquid chromatography with a charged aerosol detector (CAD). The gradient elution mode consisted of acetonitrile (Eluent A) and 0.1 M acetate buffer with pH = 5.4. Experiments were shown, that benzalkonium chloride, alkyldimethyl(ethylbenzyl)ammonium chloride, guanidine derivatives and other surfactants do not influence on the determination of didecyldimethylammonium chloride.
The proposed methods show relative measurement uncertainties better than ±5%. The linearity range for all substances were from 0.005 % to 1 % with good dynamic ranges (R² > 0.99). The result of the analysis does not depend on the ratio of cationic surfactants in disinfectants.
Lesinurad (LES) (ZURAMPIC®) is an oral urate–anion exchanger transporter 1 (URAT1) inhibitor developed by Ardea Biosciences (a subsidiary of AstraZeneca) for the treatment of hyperuricaemia associated with gout . It reduces serum uric acid (sUA) levels by inhibiting the function of the transporter proteins (URAT1 and organic anion transporter 4) involved in uric acid reabsorption in the kidney . In December 2015, LES was approved in the USA as combination therapy with a xanthine oxidase inhibitor for the treatment of hyperuricaemia associated with gout in patients who have not achieved sUA target levels with a xanthine oxidase inhibitor alone . The aim of this research was to develop a simple, rapid and precise stability-indicating high-performance liquid chromatography (HPLC) method for the quantitative estimation of LES in the presence of its degradation products. The separation was achieved with using a second generation C18-bonded monolithic silica column (Chromolith® High Resolution RP-18e, 100 × 4.6 mm, Merck KGaA) with a mobile phase containing acetonitrile: 20 mM ammonium format buffer: water, in the ratio of (20:24:56, v/v/v); pH of buffer was adjusted to 4.0 with formic acid. Flow rate was 1.5 mL.min-1, column temperature was 40 °C, injection volume was 0.3 µL and the compounds were monitored by photodiode array detector set at 228 nm.
Extreme stress conditions were applied on the samples, in addition to the ones recommended by ICH, and all were analyzed by the proposed method. Major degradation of LES was observed under acidic, alkali and oxidation conditions. The described method was validated as per ICH Q2(R1) guideline, and validation results such as system suitability, linearity, accuracy, precision, specificity and robustness were within acceptable limits. The method was found to be safe and suitable for quantitative estimation of LES in pharmaceutical preparations.
1. Miner, J.N., et al., Lesinurad, a novel, oral compound for gout, acts to decrease serum uric acid through inhibition of urate transporters in the kidney. Arthritis research & therapy, 2016. 18(1): p. 214.
2. Fleischmann, R., et al., Pharmacodynamic, pharmacokinetic and tolerability evaluation of concomitant administration of lesinurad and febuxostat in gout patients with hyperuricaemia. Rheumatology, 2014. 53(12): p. 2167-2174.
3. Hoy, S.M., Lesinurad: first global approval. Drugs, 2016. 76(4): p. 509-516.
A pre-concentration and determination method for antibiotic residues in milk samples was developed based on cloud point extraction (CPE) and HPLC-DAD analysis. Amoxicilline and chloramphenicol molecules was extracted to surfactant phases of poly ethylene glycol (PEG-6000) in the presence of pH:7.0 buffer and high electrolyte concentration. The samples were centrifuged in order to increase phase separation and then diluted and filtered by 0.45 μm membrane filter prior to HPLC determinations. Experimental variables were optimized and examined such as concentration of electrolyte and surfactant, pH, time effect. All analytical merits were calculated by using experimental results such as detection limit, linear range, preconcentration factor.
In developed method, determination of Amoxicilline and Chloramphenicol molecules in the surfactant rich phase was carried out by isocratic elution of su;acetonitrile (70:30) solvents. All analysis were performed with DAD detector at 273 nm and 276 nm througtout study. By optimization all experimental parameters, linear ranges for both wavelengths were calculated as 10-1000 ng mL^(-1) and 25-800 ng mL-1, respectively. Detection limits were 2.98 and 7.46 ng mL-1 for two wavelenghts while relative standard deviations (RSD%) were lower than 4.20 % for 100 ng mL-1 Amoxicilline and chloramphenicol. Finally, the developed method was applied to milk samples.
"Acknowledge: This study has been supported by Sivas Cumhuriyet University Scientific Research Projects Commission as the research projects with the ECZ-048 code."
Chiral imidazole derivatives are widely used human and veterinary drugs and also agrochemicals and it’s as an important category of antifungal agents. Analytical methods used for the separation of imidazole type of pharmaceuticals include HPLC, CE, CEC, etc., Furthermore, CE technique has a great interest for the separation of enantiomers of the chiral compounds.
The instrumental parameters using injection by pressure at 50 mbar 3s with 15°C of separation temperature, and 30 kV of applied voltage. The concentration of Heptakis (2, 3, 6 tris-O-methyl)-β-CD was ﬁrst varied in the range of 1–100 mM using initially 50 mM phosphate buffer solution and acidic pH (pH 2.5).
All studied enantiomers of chiral imidazole derivatives was successfully separated, the migration time increased when the concentration of Heptakis (2, 3,6 tris-O-methyl)-β-CD increased and improved the excellent resolution of peaks.
The observation for isoconazole (ISO) is while increasing the concentration of CD the resoluiton was decreasing. The optimum CD concentration was found 6 mM for ISO, it reached the highest resolution (R= 1.39, α= 1.07) with reasonable analysis time (6 min). In the case of ketoconazole (KET), resolution of the enantiomers increasing when the concentration was increasing. The best separation was achieved with the 100 mM CD with reasonable analysis time (6.5 min). For miconazole and tioconazole baseline separation of the enantiomers could not be obtained. Lastly, sertaconazole, has the good resolution by using 50 mM of CD. The analysis completed around 17 minute with the baseline separation.
As a result of this study, Heptakis (2, 3,6 tris-O-methyl)-β-CD was found as good alternative for the separation of enantiomers of some chiral imidazole derivatives
The authors would like to thank University of Tahri Mohamed Bechar for supplying internship and their financial assistance with this project. And lot of thank for Department of analytical chemistry faculty of pharmacy of Ankara University for Scholarly resources and for providing labs for this work.
A precise, simple and accurate method was developed and validated for estimation of toltrazuril in oral solution, reversed phase high performance liquid chromatographic ( RP – HPLC ) method was developed for routine quantitation.
Chromatographic separation was achieved on a BDS Hypersil C18 ( 5µ, 250x4.6 mm) using mobile phase and degassed mixture of acetonitrile: buffer solution pH 3,5 ( ajuster 1% O-phosphoric Acid) ( 45-55 V/V) at a flow rate (1 mL / min) with UV detection at 240 nm.
The method has been validated for linearity, accurancy and precision.
In RP-HPLC method, the calibration graphs were linear in the concentration range (2.5 - 7.5 µg/mL) for active ingredient pharmaceutical.
The results of this study are rapid, accurate and precise. Each analysis required no longer than 15 min. Therefore, the proposed method can be used for routine analysis of toltrazuril in liquid pharmaceutical oral solutions.
Meropenem is a carbapenem antibiotic that is relatively stable against dehydropeptidase-1 in humans and used parenterally. For this reason, there is no need to add DHP-1 inhibitor. Meropenem, bacterial wall synthesis exerts a bactericidal action by disrupting vital.In this study, a new, sensitive and selective high performance liquid chromatographic method was developed for the determination of Meropenem in human serum. In the developed method, C18 column (3,9 x 150 mm; 5 µm) was selected as stationary phase at 30°C and methanol: acetic acid solution mixture was used as mobile phase with gradient programme. Chromatographic separation was carried out at a flow rate of 1 mL/min and detection was performed at 300 nm with diode array detector (DAD) detector. Doripenem was selected as an internal standard and the analytes were extracted from serum using protein precipitation method with ortho-phosphoric acid: methanol. Detection wavelength was selected as 300 nm. The developed method was validated according to ICH guidelines. The calibration curve was linear over a concentration range of 0.8-240 µg/mL with correlation coefficients of 0.9987. The limit of detection and limit of quantification values were found as 0.08 and 0.3 µg/mL, respectively. In order to test the clinical applicability of this method, serum samples were collected from patient volunteers at different time intervals and therapeutic drug monitoring of Meropenem has been investigated.
Guaifenesin is an orally used expectorant in the treatment of allergy, common cold and upper respiratory tract infection (1). This substance reduces the viscosity of mucus secretion by reducing adhesiveness and surface tension. Guaifenesin (3-(2-methoxyphenoxy)-1,2-propanediol), also referred to as glyceryl guaiacolate ether, was originally derived from the guaiac tree. Various drug-substance manufacturers now make guaifenesin synthetically, and it has current approval by the US Food and Drug Administration as a safe and effective expectorant (2).
In this study, voltammetric analysis of the guaifenesin and its determination from the pharmaceutical dosage form were performed by cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry using boron doped diamond electrode. Firstly, the effect of pH on the redox reaction of guaifenesin was carried out using different buffer solutions to determine the optimum supporting electrolyte. As a result of pH scan, guaifenesin gave an irreversible anodic peak at all pHs and 0.5 M acetate buffer solution at pH 3.5 was selected as supporting electrolyte for further studies. Scan rate study showed that the oxidation reaction of guaifenesin was diffusion controlled. In the calibration study, the linearity ranges for differential pulse voltammetry and square wave voltammetry were 4×10-7 ˗ 1×10-4 M (r=0.998) and 8×10-7 ˗ 1×10-4 M (r=0.997), respectively. Limit of detection values (LOD) were calculated as 1.47×10-9 M for differential pulse voltammetry and 2.92×10-9 M for square wave voltammetry.
Quantitative determination of guaifenesin from the pharmaceutical dosage form was carried out without any pre-separation and filtration steps. Consequently, sensitive and fast methods with high accuracy and precision were developed for the voltammetric analysis of guaifenesin.
1. Bankar, A. A., Lokhande, S. R., Sawant, R. and Bhagat, A. R., 2013. Spectrophotometric estimation of guaifenesin and salbutamol in pure and tablet dosage form by using different methods, Der Pharma Chemica, 5, 3, 92-97.
2. Seagrave, J., Albrecht, H., Park, Y. S., Rubin, B., Solomon, G., and Kim K. C., 2011. Effect of guaifenesin on mucin production, rheology, and mucociliary transport in differentiated human airway epithelial cells, Experimental Lung Research, 37, 10, 606-614.
In the developing pharmaceutical industry, it aims to work on controlled release systems of the existing one, instead of producing a new active substance. Drugs given to the body by classical means may rapidly fall below the effective level or exceed the toxic level as a result of rapid increase in plasma concentration and a rapid decrease to the next administration. Controlled drug release allows the active substance to be released regionally or systematically at predetermined rates and at specific time intervals .The main target in controlled drug release is to keep the active substance concentration in the blood plasma constant.
Hydrogels are cross-linked networks of water-soluble polymers. Hydrogels are widely used in clinical applications, in experimental medicine, tissue engineering and regenerative medicine, diagnostic, cellular immobilization, separation of biomolecules or cells, and barrier materials that regulate biological adhesion. Their porosity also allows the drug to be loaded into the gel matrix and then release of the drug at a rate depending on the diffusion coefficient along the gel network of the small molecule or macromolecule . Smart polymers have a tremendous use in a variety of applications. In particular, intelligent polymeric drug delivery systems have been investigated as intelligent delivery systems released at the appropriate time and at the site of action of drugs in response to specific physiological triggers. We investigated the responses of hydrogels containing cefotaxime sodium to changes in pH. pH-sensitive polymers consist of an acidic or basic group that can accept or release a proton in response to changes in environmental pH. One advantage of pH-sensitive polymers is the rapid response of the system 
In this study, cefotaxime sodium and their metal complexes active substance in antibiotic class was preferred as a model drug. Cefotaxime sodium is the main active agent of drugs used against urinary tract infections, genital infections, meningitis and other central nervous system infections, skin and soft tissue infections, bone and joint infections. Controlled release systems are intended to increase the duration of the drug and the effectiveness of the drug in the treatment of these diseases.
: Bhowmik, D., Gopinath, H., Kumar B.P., Duraivel, S., K. P., Kumar, K.P.S., Controlled Release Drug Delivery Systems. The Pharma Innovatıon Journal, 2012, 1, 24-32.
: Hoare T.R., Kohane D.S., Hydrogels in drug delivery: Progress and challenges, Polymer, 2008, 49 1993-2007.
: Li M.H., Keller P., Stimuli-responsive polymer vesicles, Soft Matter, 2009, 5, 927–937
Tribulus terrestris L. is recognized as one of the best medicinal plant of polymorphic pharmacological efficiency and therapeutic action in modern medicine. By numerous researches it has been established that T.terrestris affects almost on all vital functions of an organism that is caused by the biologically active substances which are contained in the plant.
We have received new data during the study of T. terrestris of the Georgian flora.
Three C13-norisoprenoids, Damascone and Ionone type megastigmane glycosides and 5 nucleosides (adenosine, guanosine, cytidine, uridine and adenine) were isolated from the aqueous alcoholic extract of air-dried leaves of T. terrestris by purifying and further chromatography on the Diaion HP-20, Sephadex LH-20 and silica gel columns, one of which is a new organic compound; it called vajikoside (Fig.). The structures of the isolated compounds were elucidated using mono- and two-dimensional NMR experiments (1H, 13C, HSQC, HMBC, COSY), as well as mass spectroscopy (ESI/MS).
Study of analgesic activity of T.terrestris fruits’. The extract exhibited analgesic effect. Non-opioid mechanism of action is suggested, presumably due to inhibition of the synthesis of prostaglandins. Additional pharmacological study of T.terrestris fruit extract will be carried out along with other research activities in order to develop natural analgesic remedy based on previously mentioned extract.
In medicine, Coloring agents make products look better or make it easier to distinguish products of similar shape, and have the effect of preventing the decomposition of fragile contents in the light. However, Safety issues are being raised. For example, Yellow No. 4 brings weight loss, allergy, asthma, diarrhea, HLD depression and Yellow No. 5 brings headache, urticaria, asthma. Red No. 3 is a carcinogen which brings atopic dermatitis, concentration disorder, hyperactivity and Red No. 2 is kidney disorder, cancer induction. Green No. 3 brings gastrointestinal disorder, Skin rash, Intestinal cell destruction, Blue No. 1 bring ADHD, asthma, allergen induced and Blue No. 2 brings ADHD, allergy. In Korea, UV-Vis and TLC are used as identification method and quantitative test method for tar color reference method in medicines. Therefore, it is difficult to carry out the present method when adding impurities to the pigment standard as the US FDA regulations. We use High-performance Liquid Chromatography-Photodiode Array Detector (HPLC-PDA) method based on the latest research trends for tar color analysis. We selected 7 of the 42 colorants that are currently used in the domestic market (Allura Red AC, New Coccine, Phloxine B, Sudan III, Brilliant Blue FCF, Sunset Yellow FCF, Tartrazine). Our reference was made to HPLC analysis of the same tar pigment as described in the latest version of Korea Food Code. The standards were dissolved in water to give a concentration of 1000 mg/L, and diluted to 1, 5, 10, 15 and 25 μg/mL with 10 mM Ammonium acetate solution and analyzed by HPLC-PDA. The wavelengths of the DAD were set to 254, 520 and 540 nm for red, 254 and 630 nm for blue, and 254, 420 and 520 nm for yellow. As a result, most of the pigments exhibited a high molar extinction coefficient at the set wavelength, and some of the pigments had a high absorbance at 254 nm. The R2 value of the linearity was over 0.99, and RSD was mostly less than 1%. In addition, when analyzed at 230 nm for comparison with the raw materials used in actual drug manufacturing, it was confirmed that the raw material contained impurities. In the future, we will use the QSAR tool to check the genotoxicity of impurities in each tar coloring agent. This research was supported by a grant (19172MFDS126) from Ministry of Food and Drug Safety in 2019.
In this study, a novel and sensitive electrochemical nanosensor for the determination of anti-HIV drug Rilpivirine is proposed using carbon quantum dots co-catalyzed with multiwalled carbon nanotubes and silver nanoparticles. Prior to electrochemical analyses of Rilpivirine, Surface characterictics were achieved using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) technique, scanning electron microscopic(SEM) technique, and SEM armed with EDX analysis. The Rilpivirine showed two irreversible oxidation peaks at 1.20 V and 1.42 V, at all the investigated pH values. The cyclic voltammetry results demonstrated excellent electrocatalytic activity of the modified electrode toward the oxidation of Rilpivirine as endorsed by the enhanced current responses compared to bare electrode. For the analytical application, adsorptive stripping differential pulse voltammetric (AdSDPV) technique was used and all operational parameters were optimized. Optimum accumulation potential and time were found as 0 V and 60 s, respectively. The influence of 500 fold higher concentration interfering agents was studied to examine the selectivity of the designed sensor.
The linearity range was found to be 1.00×10−9 to 7.00×10-9 M, and nanosensor displayed an excellent detection limit of 3.00×10-11 M and 6.40×10-11 M for peak 1 and peak 2 by AdSDPV, respectively. The developed nanosensor was successfully applied for the determination of Rilpivirine in biological fluids, urine and synthetic human serum as a real sample. Moreover, in order to evaluate the analytical applicability of the proposed method, it was applied to the determination of Rilpivirine with 1.79×10-10 M, 4.47×10-10 M in serum samples, 5.26×10-10 M and 8.27×10-10 M in urine samples for peak 1 and peak 2, respectively.
Fabricating a specific nanocomposite film with excellent electrocatalytic activity and a large surface area is an important aspect for its application as an electrochemical sensor. In this work, for the first time, an ultrahigh performance sensor based on an amine-functionalized multi-walled carbon nanotubes and over-oxidized polypyrrole modified glassy carbon electrode (oo-PPy/MWCNTs-NH2/GCE) was developed for the determination of zafirlukast. The composition, morphologies, and nanostructures characteristics of the oo-PPy/MWCNTs-NH2 composite film were completely studied by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electrochemical impedance spectroscopy (EIS). Electrochemical oxidation of zafirlukast (ZAF) was studied on the bare, NH2-functionalized multi-walled carbon nanotubes and over-oxidized polypyrrole modified (oo-PPy/MWCNTs-NH2/GCE) glassy carbon electrodes by cyclic, differential pulse and square wave voltammetric techniques. The oo-PPy/MWCNTs-NH2 composite film electrode exhibited an excellent electrocatalytic activity with enhanced electrochemical response towards the oxidation of zafirlukast, due to the more negative charge density of oo-Ppy on a 1D structure of MWCNTs-NH2 layer as well as high surface area to volume ratio that improved the adsorption for ZAF. The effects of some parameters on the ZAF response such as pH, the amount of MWCNTs-NH2, concentration of SDS and Py monomer, the number of cycles for the electropolymerization in the modification of electrode were optimized. The MWCNTs-NH2 and oo-PPy based sensor possessed an excellent features toward ZAF. Thus, with seeming stability, anti-interference performance, and selectivity, the suggested sensor have been successfully applied for the determination of ZAF in pharmaceuticals and biological samples.
The nonapeptide bradykinin is endogenously present in low femtomolar plasma concentrations and subsequently difficult to detect reliably by high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS). Since peptides adsorb to surfaces, the peptide-individual examination of materials and solvents helps to minimize losses. Further, the addition of modifiers to the chromatographic mobile phase can enhance signal intensity in peptide analysis by LC-MS/MS. Finding the optimal settings facilitates the measurement of the low-abundant bradykinin.
A design of experiments (DoE) approach (MODDE Pro 12.0, Umetrics) was applied to improve the signal intensity of bradykinin in LC-MS/MS. By means of a full-factorial screening, the sample collection materials standard glass, LC-MS glass, polystyrene, polypropylene and protein low-binding polypropylene were examined in 18 experiments with three centre-points, performed in triplicates. For the injection solvents, a mobile phase composition (90/10 water/methanol, 0.1% formic acid (FA)), the extraction solvent (25/75 acetonitrile/water, 0.3% trifluoracetic acid) and the stock solution solvent (water, 0.1% FA) were analysed.
To further optimize the chromatographic mobile phase composition of the gradient separation, a D-optimal was designed with 23 runs and one centre-point, analysed in quintuplicates. Water and the organic solvent, either methanol or acetonitrile, were mixed with one of the three modifiers dimethyl sulfoxide (DMSO), propionic acid (PA) or ethylene glycol (EG) (investigation range: 0-5%), as well as with FA (investigation range: 0.1-1%).
For a significant and reliable model, the reproducibility and the goodness of fit (R²) and of prediction (Q²) were at least expected to be greater than 0.5 with a maximal difference of 0.3 of the latter two.
The screening design, characterized by a reproducibility of 0.85, revealed an improvement of factor 12.0 when comparing the highest signal response, observed in polypropylene, to the lowest, in LC-MS glass. The protein low-binding material performed similar to polypropylene but was less affected by the use of the different solutions. However, when using the extraction solvent, the influence of materials was eliminated and closely reached maximal values observed in polypropylene.
The D-optimal design, classified by R²=0.91, Q²=0.88 and a reproducibility of 0.98, calculated an optimal mobile phase composition of 3.7% DMSO and 0.1% FA in methanol/water (Fig.1). The inclusion of DMSO led to an increase of factor 1.9 compared to 0.1% FA in methanol. Nevertheless, a similar enhancement was also calculated for the optimized concentrations with EG (1.8), whereas PA performed slightly below (1.6). Acetonitrile is less suitable for the determination of bradykinin, as the optimized composition (5.0% EG, 1.0% FA) accounts only for 0.5 of the optimum in methanol. When comparing the optimal setting to the poorest (0.1% FA, acetonitrile), an augmentation of factor 5.7 can be made up.
The application of a DoE approach was used to effectively investigate surface adsorption and increase the signal intensity in LC-MS/MS within few experiments. A total improvement of factor 12.0 for the injection solvent and sample collection material and of 5.7 regarding the mobile phase could be revealed. Those results form the basis to enable low concentration measurements of bradykinin.
Osteopontin (OPN) is an osteoblast-secreted protein with an aspartic acid-rich, highly phosphorylated, and glycosylated structure. OPN can easily bind to integrins, tumor cells, extracellular matrix and calcium, and is related to bone diseases, various cancers, inflammation etc. Elevated OPN concentrations have been reported in many diseases, and even higher levels than 1 µg/mL OPN in human plasma have been detected in many individual cases, such as heart failure, prostate carcinoma, breast cancer, cervix cancer and so on. Thus, OPN can be used as a biomarker by comparing the levels found for patients potentially subjected to these diseases with the levels found for healthy controls.
The commonly used methods for OPN analysis demands well characterized antibodies with high specificity for OPN in plasma. Immunoassay methods are very common and often highly useful. However, there are some intrinsic drawbacks concerning antibody specificity, cost etc. Here, an antiboby-free method based on DEAE-Cibacron blue 3GA (DEAE-CB) was used to extract recombinant osteopontin (rhOPN) from human plasma, and to deplete abundant plasma proteins (Fig. 1). Using selected buffer systems, rhOPN and human serum albumin (HSA) could be bound to DEAE-CB, while immunoglobulin G (IgG) was excluded. The bound rhOPN could then be separated from HSA by using different sequential elution buffers. By this method, 1 µg/mL rhOPN could be separated from the major part of the most abundant proteins in human plasma. After trypsin digestion, the extracted rhOPN could be successfully detected and identified by MALDI-TOF MS/MS using the m/z 1854.898 peptide and its fragments.
Keywords: Osteopontin, preconcentration, MALDI
Fig 1. Schematics of the enrichment method for rhOPN in plasma samples (sample and buffer volumes were doubled for 1 µg/ml rhOPN in plasma samples). 
 Y. Zhou, J. Romson and Å. Emmer, PLoS ONE 14 (2019) e0213405.
Ovarian cancer is one of the main causes of deaths from gynaecological cancer. Ovarian cancer causes many deaths due to the lack of adequate physical examination and the absence of specific symptoms. Therefore, this situation usually detected in late stages and after the metastasis has occurred (Chen et al., 2017). CA125 is important in the diagnosis of ovarian cancer. The detection of CA125 biomarkers in the diagnosis of ovarian cancer is routinely performed. Although CA 125 immunosensors for determination of CA 125 are available in the literature, it is important to develop label-free CA125 immunosensors that are fast, practical, cost-effective, and suitable for point of care.
In this study, label-free CA125 biosensor is prepared on screen-printed electrodes and electrochemical characterizations are performed. For this purpose, firstly, the screen-printed electrodes (SPCE) were modified with reduced graphene oxide (RGO), polyneutral red (PNR) and gold nanoparticule (AuNP). Then, the surfaces of the electrodes (SPCE/RGO/PNR/AuNP) were modified by GA, Anti-CA125, BSA and CA125, respectively, and the CA125 biosensor was prepared (SPCE/RGO/PTH/AuNP/GA/Anti-CA125/BSA/CA125). Schematic representation of preparation of CA125 biosensor is given in Figure 1. The incubation times of antigen and antibodies, pH and amount of antibodies of the prepared immunosensors were optimized. The preparation stages of immunosensors and optimization studies were characterized by electrochemical methods. CV, DPV, SWV and EIS were used as electrochemical analysis methods.
This project was supported by Tubitak (Project No: 118R030).
1. Chen, F., Liu, Y., Chen, C., Gong, H., Cai, C., Chen, X., 2017. “Respective and Simultaneous Detection Tumor Markers CA125 and STIP1 Using Aptamer-Based Fluorescent and RLS Sensors”, Sensors Actuators B Chem. 245, 470–476.
New chelating polymeric sorbent on the basis of maleic anhydride styrene copolymer by the chemically modification with streptocide has been synthesized. Sorbent has shows complexing properties. The synthesized sorbent has been investigated by IR spectroscopy. It′s sorption characteristics toward palladium(II) ions has been studied.
|CMe x•10-3, mol•l-1||0,2||0,4||0,8||1,0||2,0||4,0||6,0||8,0|
This poster reports the performance comparison between exhaustive and equilibrium extraction using classical Avantor C18 solid phase extraction (SPE) sorbent, hydrophilic-lipophilic balance (HLB) SPE sorbent, Sep-Pak C18 SPE sorbent, novel sol-gel Carbowax 20M (sol-gel CW 20M) SPE sorbent and sol-gel CW 20M coated fabric phase sorptive extraction (FPSE) media for the simultaneous extraction and analysis of three inflammatory bowel disease (IBD) drugs that possess logP values (polarity) ranging from 1.66 for cortisone, 2.30 for ciprofloxacin, and 2.92 for sulfasalazine). Both the commercial SPE phases and in-house synthesized sol-gel CW 20M SPE phases were loaded in SPE cartridges and the extractions were carried out under exhaustive extraction mode. FPSE was carried out under equilibrium extraction mode. The drug compounds were resolved using a Luna C18 column (250 mm × 4.6 mm; 5 m particle size) in gradient elution mode within 20 minutes and the method was validated in compliance with international guidelines for the bioanalytical method validation. Novel in-house synthesized and loaded sol-gel CW 20M SPE sorbent cartridges were characterized in terms of extraction capability, breakthrough volume, retention volume, hold-up volume, number of theoretical plate, and retention factor.
In these researches, was highlighted that for the tested compounds is nowadays not available a “universal” phase. In fact, for some analytes were not possible to evaluate the breakthrough volume (VB), retention volume (VR), hold-up volume (VM), retention factor (k), and theoretical plates number (N), because no quantitative data were obtained after SPE steps. Consequently, was not possible to perform the analysis by Boltzmann’s function due to a “floating point error”.
Comparing breakthrough volume and enrichment factors data allowed us to evaluate the performance of both FPSE and SPE techniques. SPE technique shows the highest enrichment factors; consequently, this method is more suitable for samples with low analytes concentration.
An ultra-fast and simple method for the ABO and rhesus (Rh) blood group typing from individual erythrocyte is proposed in this study. Blood group-specific antibodies immobilized to gold nanoparticle (BG-AuNP) were utilized for the identification of blood groups from individual erythrocytes by objective type dark field microscopy. The scattering of free BG-AuNP and its Brownian motion as well as BG-AuNP attached on erythrocytes could easily be observed by dark field microscopy with low N.A. objective and low-cost complementary metal-oxide-semiconductor camera. All of the erythrocytes with different blood group antigens including A, B, D, C, c, E, e could be exactly identified by BG-AuNP immediately when mixed with suspension of red blood cells without any incubation. The specificity of this method was confirmed by testing of antigen-identified screening cells that are used for antibody screening in blood banks of hospitals. As a result of high-speed antigen identification by direct observation of BG-AuNP scattering on attached erythrocytes, the waiting time for the blood group typing is thereby minimized to a few seconds. Therefore, the BG-AuNP combined with objective type dark field microscopy demonstrated the feasibility and advantage in the emergency transfusion as a result of unmatched transfusion caused by unknown blood group of patients.
We report on a concentric thin layer cell accommodating pencil graphite disposable working electrode with a non-standard diameter of 0.2 mm (Pentel Ain Stein, Japan). Prior to flow experiments, electrochemical properties of the pencil leads were investigated using cyclic voltammetry of potassium ferricyanide in aqueous and ferrocene in non-aqueous environment with the result that the 0.2 mm pencil graphite surface surface has a character of microelectrode array. Then, the pencil lead was applied in in-house designed flow cell which was tested in conventional HPLC setup. Operation in mobile phases containing both low and high content of organic solvents provided satisfactory results in HPLC analyses of phenolic acids and tocopherol isomers was investigated. HPLC separation of model mixtures of gentisic, caffeic and dihydrocaffeic acids showed a remarkable electrolytic efficiency exceeding 80% at 200, and 50% at 500 μL/min, while for gentisic acid the limit of detection (LOD) was 0.4 nmoL L−1 at 20 microliter sample loading (8 fmoL on-column). Similar LODs (e.g. 0.8 nmoL L−1 for delta-tocopherol) were found in the model separation of tocopherol isomers in non-aqueous mobile phase. The developed flow-through detector allows an easy replacement of pencil graphite working electrode in a highly reproducible manner. The relative standard deviation for the HPLC analysis of tocopherol isomers was of 5.3% (n=3, C=500 nmoL L−1). Near-coulometric operation at normal flow rates and sub- or nanomolar detection limits was demonstrated for mobile phases containing low and high content of organic solvents.The combination of simple construction, excellent electrochemical performance and hydrodynamics identical to that of commercial UV-VIS HPLC detector suggests that the proposed device is a viable low-cost alternative to commercially available electrochemical detectors.
Since naproxen is one of the most widely used non-steroidal anti-inflammatory pain medications, it is found in the urban wastewater, surface waters and also in drinking water sources. Even at very low doses, naproxen adversely affects human health and causes environmental pollution. Therefore, removal of toxic drug compounds, such as naproxen from water has been one of the increasingly important environmental problems in recent years and it is important to develop alternative treatment methods for the removal of these compounds causing significant problems in the environment. As novel treatment methods were studied for removal of these micro-organic pollutants, the majority of the investigations highlighted the applications of phase-change processes, such as adsorption or membrane methods. Among the methods used for treatment of wastewater, adsorption is preferred because of the ease of application and high removal efficiencies. Various materials are used for water treatment, such as chitosan, montmorillonite, activated carbon, biochar and carbon nanotube. Among them, biochar has unique chemical, physical and biological properties, such as large specific surface area, high pore volume, enriched surface functional groups and high mineral content. Because of these properties, biochar is a preferred material in many areas including reduction of greenhouse gas emissions, soil remediation, catalyst and wastewater treatment.
In this study, naproxen removal from aqueous solutions was investigated by using the batch adsorption method. The peanut husk used as biomass was pyrolysed at two different temperatures (550°C and 800°C) and prepared biochar were used as adsorbent. Prepared biochar was characterized by SEM, XRD, FTIR and BET analyzes. The characterization results showed that the physicochemical properties of the peanut husk were extremely changed. In batch adsorption experiments, the effect of adsorbent amount, temperature and pH on adsorption were investigated. The equilibrium data were evaluated using the Langmuir and Freundlich model equations and the kinetic data were evaluated with pseudo first order, second order and Elovich kinetic models. In addition, the adsorption thermodynamics of the proposed method in the optimum conditions was also investigated.
In recent years, the increase in industrialization has caused a wide range of pollutants which spread the environment and following harm it seriously. Among these pollutants, many heavy metal cations are considered as dangerous environmental pollutants even at trace levels. In general, the toxicity of it is relatively low and it is also a necessary element for human diet because of vitamin B12. However, its large amounts can cause toxicological effects including vasodilatation, flushing and cardiomyopathy for humans and animals. Therefore, the sensitive, accurate and precise analytical methods should be used for the determination of it especially in the food, water and environment samples. Cobalt are generally determined in various real samples by using different methods, such as atomic absorption spectrometry (AAS), inductively coupled plasma atomic emission spectrometry (ICPAES), and inductively coupled plasma mass spectrometry (ICPMS). Among them, AAS is still widely used due to availability of the instrumentation in routine laboratory, its simplicity, relatively higher speed, precision and accuracy. However, determination of cobalt by AAS is a problem owing to its low concentrations in real samples including complex matrix. Therefore, researchers used some separation and preconcentration methods, such as solid phase extraction, solvent extraction, cloud point extraction, ion exchange, coprecipitation, and electroanalytical techniques before detection step by AAS.
In this study, we have developed a simple analytical methodology using solid phase extraction method for the separation and preconcentration of Co(II) and AAS was used in the detection step. The effect of some experimental parameters on the separation and preconcentration of Co(II), such as pH, type and concentration of eluent, flow rate of sample and eluent solution, resin amount, sample volume and interference effects were investigated and their optimum values were determined. During the separation and preconcentration of Co(II), a column filled with Amberlite CG-120 resin was employed. As far as we can ascertain, Amberlite CG-120 resin has not been used for the separation and preconcentration of Co(II). Furthermore, the developed method was used for the determination of Co(II) in the drinking and waste water samples. The accuracy of the method was also tested by the certified reference material of TMDA-70.2 Ontario Lake Water at a 95% confidence level.
We report on the straightforward preparation of graphite nanomaterials (GNMs) through a direct graphite-to-substrate electric discharge at ambient conditions at 1.2 kV between pencil leads and low-cost graphite screen-printed electrodes (SPEs). The so-modified sparked GNM-SPE was characterized by Raman spectroscopy, scanning electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. GNM-SPE sparked electrodes endowed sensitivity to plain SPEs to the cathodic voltammetric detection of various nitroaromatic explosives. Different commercially available pencil leads including “graphite pencil” (Faber−Castell, Castell 9000) of different degrees of hardness (4H, 2H, HB, 2B and 4B), “high-purity graphite leads” (Pilot, ENO−G, HB), “needle-crystal leads” (Uni-ball, Uni, HB) and “nanodiamonds leads” (Uni-ball, Nano−Dia, HB) were examined. Taking as criterion the highest response to the electro reduction of 2,4,6-trinitrotoluene (TNT), Castell 9000 (2B) pencil was selected as optimum. SPEs that have been modified with 200 sparking cycles showed an excellent repeatability (RSD50ppb = 1.8%, n=5), reproducibility (RSD10ppb = 3.0% and RSD50ppb = 2.8%, n=5) and linear response over the concentration range 1−100 ppb TNT. Data fit the equation I (μA) = (0.0137 ± 0.0002) [TNT(ppb)] − (0.0043 ± 0.0020), R2 = 0.9989, while the limit of detection based on the 3σ/m criterion was calculated 0.44 ppb. The interference effect of other nitroaromatic explosives and masking compounds, which are used to hinder the detection of TNT, was extensively investigated.
Moreover, GNM-SPE sparked electrodes were successfully applied to the determination of TNT in drinking water samples fortified with 2, 5 and 10 ppb TNT. Recovery was from 101±8 to 109±7%. Results demonstrated a new type of GNM-SPE low cost electrodes lend themselves to extremely simple preparation while offering enhanced detection capabilities and a wide-scope of applicability. Remarkably, GNM-SPE sparked electrodes can be prepared on-demand, within 3-4 min, through a totally green and solution-free method that requires only a pencil lead and a power supply.
The advantages of dispersive solid phase microextraction using pipette tips (μ-dSPE-PT) are higher recovery due higher contact of sorbent with sample, no need of vacuum manifold, and only small volumes of samples and organic solvents needed for extraction. On the other hand, μ-dSPE-PT sorbents are expensive and only few types are commercially available. This can be a limiting factor during the development of microextraction method for samples containing e.g. analytes with differences in physicochemical properties. Mixed-mode sorbent containing reversed phase and a strong anion exchange is often necessary for the μ-dSPE-PT approach due to better selectivity and adequate recovery of different types of analytes. Due to unavailability of these tips on the market, the new extraction device was developed to facilitate extraction method based on dSPE. The analytes of interest were natural compounds from the group of flavonoids and isoflavonoids including: (i) phenolic acids with lower molecular weight and (ii) flavonoids/isoflavonoids. The analytes differ significantly in their physicochemical properties which makes their separation and extraction challenging.
The extraction device was developed and printed by 3D printer DeltiQ (Trilab, Czech Republic) with the 0.2 mm nozzle. The polyethylene terephthalate – glycol and polypropylene filaments (1.75 ± 0.05 mm, Filament-PM, Czech Republic) were used as the printing material. The temperature 250°C was set up for the first layer. Subsequently, the temperature of 240°C was applied for further printing steps. The sorbents including resin with weak anion-exchange properties, C18, and polymeric sorbent with anion-exchange groups were tested as well as their different amounts in the range of 2 mg – 120 mg. 30% methanol (MeOH) was used as a conditioning solvent. 10% MeOH with 0.1% formic acid (FA) was chosen as the optimal loading solvent. 10% FA in MeOH offered the best recovery. After thorough optimization of all parameters of this sample preparation method, the recoveries of all 13 analytes were in the range 60 – 110 %.
The analysis was carried out using previously developed UHPLC-MS/MS method at following conditions: BEH Shield RP C18 (2.1 x 100 mm; 1.7 μm) column, gradient elution with methanol and 0.1% aqueous solution of formic acid, and mass spectrometry system with triple quadrupole (Agilent 6495b).
This work was supported by the project EFSA-CDN (No. CZ.02.1.01/0.0/0.0/16_019/0000841) co-funded by ERDF, by SVV 260412 and by GAUK 1574317.
Pistachio (Pistacia vera L.) is a small tree species belonging to the Anacardiaceae family, native of the Middle East and Central Asia, and widely cultivated also in California and in Mediterranean countries such as Greece and Italy. Major producers of pistachio are Iran, United States and Turkey. Besides being a delicious nut, pistachio, due to its wholesome nutritional properties, could be considered as a functional food. According to the results of several studies, pistachios have been proven to have various groups of valuable phytochemicals such as anthocyanins, flavan-3-ols, proanthocyanidins, flavonols, isoflavones, flavanones, stilbenes and phenolic acids, possessing excellent biological activities.
Most common analytical techniques employed for analysis of such phenolic compounds are based on liquid chromatography separation coupled to photodiode array and mass spectrometry detection. However, conventional LC can present some limits, especially in terms of resolving power. A powerful alternative is represented by comprehensive two-dimensional liquid chromatography (LCxLC), where two columns of (possibly) different selectivity are connected by means of a suitable interface, most often represented by a switching valve.
In this contribution, the phenolic fraction of pistachio nuts harvested in different geographical regions was thoroughly elucidated by LCxLC-PDA-qMS, using a 150 mm microbore cyano column (2.7 μm dp), and a 50 mm superficially porous C18 column (2.7 μm dp) in the first (¹D) and second (²D), respectively. A micro LC pump was employed in ¹D of the comprehensive system, capable to deliver reproducible flow rates down to the microliter range for operation of the ¹D column (1.0 mm I.D.). A shifted ²D gradient was investigated, in order to reduce the correlation of elution patterns in the two chromatographic dimensions and to allow for an increase in the overall peak capacity.
Acknowledgments. The authors gratefully acknowledge Merck and Shimadzu for their continuous support.
The correct characterization of furocoumarins in cosmetic products is a great debated topic. At this regard despite the official regulation of the European Parliament (EC n. 1223/2009), the scientific committee for food (ISCC) and the International Fragrance Association (IFRA) are still discussing about the maximum content of psoralen in rinsing and discharging products. As well as to the most recent phototoxicity tests and to the imposed limits by the use of Photo Dyode Array (PDA) detectors.
Considering that liquid chromatography (LC) coupled to PDA is still the main analytical approach for the quantification of furocumarins, the following research focused attention on the determination of the correct detection limit (LOD) and limit of quantification (LOQ) of furocumarine in citrus essential oils, that are responsible of the presence of oxygenated heterocyclic compounds in cosmetic products.
Three different distilled essential oils (lemon, bergamot, mandarin) were used to evaluate the influence of the matrix on the LOD and LOQ calculation. Moreover, PDA calibration curves were constructed also by spiking the matrices above mentioned in order to evaluate potential coelutions and to avoid the over estimation of the target compounds.
To overcome the limitations imposed by the PDA method, a new LC method coupled to triple quadrupole mass spectrometry (QqQ MS) was validated, providing very low LOQ. Calibration curves were realized in Multiple Reaction Monitoring mode and used to quantify furocoumarins at trace level in the finished cosmetic products.
Both techniques were applied to analyze several samples, such as body wash and perfumes, providing useful information which can help the awarding bodies to establish a defined regulation.
Moreover, in order to reach an unequivocal identification of these target molecules, the Linear Retention Index approach was employed for the first time as an extra criterion to UV-Vis, MS and QqQ MS libraries through both LC-PDA and LC-QqQ MS methods. The libraries were built collecting the spectra of furocoumarin, coumarin and polymethoxyflavone standard compounds.
Adknowledges: The authors gratefully acknowledge Merck and Shimadzu for their continuous support.
Quercetin, a polyphenolic flavonoid, commonly exists in human diet such as various vegetables, fruits, grains, tea etc. Flavonoids that are strong antioxidants prevent DNA damage and possess pharmacological properties including anticancer, anti-inflammatory and antiviral activities. These biological actions are related to their mechanism of actions. In this study, the modes of interactions of quercetin and its sulfone derivatives to DNA were evaluated using UV–Vis spectrophotometry and electrochemical techniques. In particular, the interaction of double strain DNA (dsDNA) and its quercetin derivative were compared with those of quercetin standard. The approach provides a simple technique to study the in-situ binding and the values of the binding constants (Kb) of flavonoids to dsDNA were determined. Binding constants were calculated and the interactions explained with fluorescence quenching. Interaction of quercetin and its derivative with dsDNA have been also analyzed by several voltammetric techniques using glassy carbon electrode at physiological pH 7.4 and the binding constants (Kb) of flavonoids to DNA were determined.
The presence of mineral oil hydrocarbons (MOH) in food has been known since 1989, when Biedermann and co-workers (1989) reported its presence accidentally in irradiate hazelnuts. However, such a contamination problem was only brought at the attention of the public opinion 20 years later when the same authors related the presence of the high amount of MOH find in dry food to the use of recycled fibers for food contact material (Biedermann et al., 2009). The analysis of such a contaminant in food is a challenging task, mainly due to the high complexity of the matrices and the high affinity with the lipid fraction and many of its components. Due to this challenge, the use of powerful confirmatory techniques is required. The European Food Safety Authority (EFSA, 2012) proposed the use of on-line LC-GC/FID as the most effective method for the routine analysis of MOH, but the presence of false positive and the doubts on the nature of the chromatographic hump originated with this analysis remain, due also to the lack of a proper confirmatory method. Most recently, in February 2019, the European Joint Research Center (JRC, 2019) published the Guideline reporting the minimal requirements of the method to be used to investigate MOH contamination in food and extending the range of volatility considered up to C50. The goal of the present study is to optimize a GC×GC-MS/FID for the simultaneous quantification and confirmation of the results. A careful optimization is necessary to proper elute up to C50 without losing the inherent advantage of structured chromatograms obtained when using GC×GC.
Amikacin is a semi-synthetic aminoglycoside antibiotic that is derived from kanamycin A. Amikacin is synthesized by acylation with the l-(-)-γ-amino-α-hydroxybutyryl side chain at the C-1 amino group of the deoxystreptamine moiety of kanamycin A. Amikacin's unique property is that it exerts activity against more resistant gram-negative bacilli such as Acinetobacter baumanii and Pseudomonas aeruginosa . Amikacin also exerts excellent activity against most aerobic gram-negative bacilli from the Enterobacteriaceae family, including Nocardia and some Mycobacterium . There are some analytical tools such as chromatography , spectroscopy  and electrophoresis  for determination of amikacin in literature. Most of these methods needs high-cost instruments and time-consuming pretreatments for analysis. In other hand, electrochemical methods are low-cost, simple, easy with high sensitivity and selectivity. Amikacin has no oxidation peak at the surface of bare glassy carbon electrode. Gold nanoparticles (AuNPs) due to their properties such as continuity in synthesis and unique optical properties, are the perfect scaffold for the fabrication of novel biological and chemical sensors . Also, use these nanoparticles on surface electrodes as modifier, increases the efficiency of the electrodes by high mass transfer, catalysis, high surface area. In this study, a voltammetric sensor for the determination of Amikacin with gold nanostructures is proposed. Gold nanostructures were electrochemically deposited at the surface of glassy carbon using constant potential in fixed time. The time and potential of deposition was optimized. Scanning electron microscopy and diffusion reflectance spectroscopy were used for characterization of gold nanostructures. Electrodeposited gold nanostructures show oxidation-reduction peaks which decrease in presence of amikacin. We has used this point for determination of amikacin using voltammetric methods. The effect of pH and scan rate was investigated. Calibration curve obtained by plotting decreasing reduction peak currents of gold versus amikacin concentrations. The limit of detection was 2×10-9 M and dynamic linear range was 1×10-8- 5×10-4 M the ability of sensor for determination of amikacin was tested in real samples such as human serum and pharmaceutical ampules.
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Evidence of presence of antiretroviral drugs in environmental surface water is now of serious concern for both water and food stakeholders as well as environmentalists. Their presence in surface water sources is a cause for concern because these drugs work against a human immune-deficiency virus with a tendency to mutate if there is a deviation from prescription specifications. WHO has recommended Atripla, a fixed dose combination regimen pill consisting of tenofovir, efavirenz and emtricitabine as a starter for anyone recently diagnosed with HIV. It is estimated that at least 21.78 tons of Atripla are being consumed worldwide every day. With such high levels of ARVs reported in surface water, focus has shifted towards finding ways of eliminating or minimizing their presence in drinking water sources. This study reports the potential degradation of these Atripla components (emtricitabine, tenofovir and efavirenz) in water sources in the presence of light and a TiO2-based catalyst. Zidovudine, nevirapine and lamivudine have been shown to appear prominently in surface water and were also included in the study. The effects of various parameters on the degradation of the ARVs are investigated. These include initial ARV concentration, catalyst dosage and re-usability, pH, contact time as well as some matrix effects. The degradation pathways followed the first order kinetics with several intermediates and final products identified using a UHPLC-Orbitrap/MS. The mineralization products were identified using ion chromatography. The toxicity of the stable intermediates was also investigated. This study has shown that photocatalytic degradation can be a viable remediation process to convert antiretrovirals in drinking water sources to non-toxic by-products.
In this poster we aimed at the simultaneous separation and quantification of Gemcitabine and Irinotecan hydrochloride (injected both as single components and in combination) from Sprague Dawley rat plasma by using a validated method obtained through the use of a High Performance Liquid Chromatography (HPLC)-diode array detector (DAD).
Gemcitabine and Irinotecan hydrochloride were detected and quantified using a Zorbax Extend C-18 column (250 mm × 4.6 mm; 5 μm particle size) in gradient elution mode. The chromatographic analyses were carried out in 15 minutes. The analytical mode was calibrated and validated in the concentration range from 0.1 to 18 μg/mL both for Gemcitabine and Irinotecan hydrochloride. Sprague Dawley rat plasma was used to perform the analysis. 3-methylxanthine was the internal standard. The weighted-matrix matched standard curves of Gemcitabine and Irinotecan hydrochloride showed a good linearity up to 18 μg/mL. Parallelism tests were also performed to evaluate whether the over-range samples could be analyzed after dilution without affecting the analytical performance. The intra- and inter-day precision (RSD%) values of Gemcitabine and Irinotecan hydrochloride were ≤7.14% and ≤11.5%, respectively. The intra- and inter-day trueness (Bias%) values were in the range from -11.5% to 1.70% for both drugs.
The analytical mode performance was further tested after collecting Sprague Dawley rat plasma following a single-dose administration of chemotherapeutics or their association. The validated HPLC-DAD method allowed the simultaneous quantification of Gemcitabine and Irinotecan hydrochloride in the rat plasma, besides the evaluation of the pharmacokinetic parameters and drug delivery.
Neuropeptide Y (NPY) is involved in various physiological processes, including the regulation of feeding behavior and energy homeostasis and, as recently reported, the regulation of bone homeostasis. The Y1 receptor has been identified as major contributor to this latter biological effect. In fact, Y1 receptor (Y1R) has been recently recognized as a potential regulator in the local control of bone turnover, suggesting that an anti-receptor strategy may be a useful therapeutic approach to prevent and/or reverse bone loss. BIBP 3226 is a potent and selective Y1R antagonist that has been successfully used in in vitro studies showing a positive impact in bone turnover and thus providing good perspectives towards its application as a pharmacological tool for bone regeneration.
Having in mind the therapeutic potential of BIBP 3226 and also the need to elucidate receptor-antagonist internalization mechanisms, the present work targeted the development of a method based on high-performance liquid chromatography coupled to triple quadrupole-tandem mass spectrometry for determination of the low quantities of BIBP 3226 expected to be internalized by cells.
Chromatographic separation was achieved using a reversed phase Kinetex core-shell C8 column at 30 °C and elution in isocratic mode using a mixture of acetonitrile and water (30:70, v/v), containing 0.1% (v/v) formic acid, at 0.25 mL min⁻¹. Each run required only 5.0 min, with a retention time of 3.7 min for the target compound. The MS/MS was operated in positive ionization mode (ESI+) and data were acquired in selected reaction monitoring mode (m/z 474>167 for quantification and m/z 474>107 for identity confirmation). Calibration curves were linear for concentrations ranging from 0.25 to 30 ng mL⁻¹ with LOD and LOQ values as low as 0.1 and 0.3 pg in cell extracts and 16 and 48 pg in supernatant culture media, respectively. The method proved to be sensitive, selective, precise, accurate, and no significant matrix effect was observed. BIBP 3226 was successfully quantified in cell extracts and supernatants obtained from internalization assays performed with two cultures exhibiting different levels of NPY Y1 receptor expression. The determined values ranged from 1.30 ± 0.05 pg for Wt bone marrow cells to 107 ± 1 pg for MCF7 cells. Therefore, the determined amount of BIBP 3226 was related to the level of receptor expression.
Acknowledgements: This work received financial support from the European Union (FEDER funds) and National Funds (FCT/MEC, Fundação para a Ciência e a Tecnologia and Ministério da Educação e Ciência) under the Partnership Agreement PT2020 UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265, project NORTE-01-0145-FEDER-000012, project "Institute for Research and Innovation in Health Sciences" (POCI-01-0145-FEDER-007274). E. M. P. Silva acknowledges funding from FEDER - Operational Competitiveness and Internationalization Programme (COMPETE 2020) through project NORTE-01-0145-FEDER-000011.
Persistent infection with human papilloma virus (HPV) can cause malignant tissue transformation and lead to various types of cancers, most often cervical cancer in women . HPV-16 and HPV-18 are two most oncogenic high-risk HPV types which cause over 70% of HPV-positive cervical carcinomas. Current detection methods  involve complex protocols, need for skilled personnel and expensive reagents and instruments.
Electrochemical methods of detection may circumvent these challenges by offering rapid, simple and inexpensive assays . In our work, we focused on development of such assay by combining loop-mediated isothermal amplification (LAMP) reaction to amplify DNA from cancer cells, magnetic beads for improved selectivity and amperometric measurement performed on carbon electrode arrays for parallel measurements to speed up the protocol. We were able to determine and discriminate HPV16 and HPV18 types not only in cervical cancer cell lines, but more importantly in clinical samples isolated from cervical smears obtained during gynecological examinations .
Currently, we are adapting this method also for detection of oncoviral mRNAs, E6 and E7 mRNAs, which better reflect virus activity and may thus help to reveal disease progression before cellular changes become visible in classical cytological examination.
Authors acknowledge GACR 17-08971S and MEYS-NPS I-LO1413.
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In the present work we analyzed the hydrophobicity and hydrophilicity properties of several non-steroidal anti-inflammatory drugs (NSAIDs) by using molecular dynamic simulation which is able to describe the relationship between chemical properties and motion behaviour of a small molecule (Fig 1). The greatest difficulty of the simultaneous extraction of drugs from different therapeutic classes concerns the choice of the best SPE sorbent to give an acceptable recovery of all the analytes having different physicochemical properties.
The four parameters obtained from the molecular dynamic simulation were used independently to investigate how these parameters correlate with the extraction recovery of NSAIDs using solid phase extraction. The highest correlation belongs to the theoretical descriptor representing the hydrophobicity of the compounds (Fig 2). The Pearson correlation is 0.95, indicating an high positive correlation between hydrophobicity and the recovery percentage (The p-values was 0.0003). The HPLC-PDA method was validated according to the FDA guidelines. The recovery of the NSAIDs were within 76.6% to 97.4% with an high correlation between the theoretical and experimental values. The correlation was obtained using a “parameter free” correlation, thus without training the parameters through experimental data.
This parameter-free correlation could be an useful tool for predicting analyte sorbent interaction in order to save time, labour and cost.
Furthermore, an important advantage of the proposed method is to provide a set of four parameters linked to four different chemical properties of the analytes each of them can be used to investigate their behavior regarding the specific choice of the sorbent for solid phase extraction.
The use of a substance that may influence both athletes performance and health while having a high potential for misuse is contrary to the “Fair Play” rules. According to World Anti-Doping Agency nicotine is not officially recognized as a doping agent, but was included in the 2012 Monitoring Program in order to assess the prevalence of its use by the athletes. Nicotine is a psychomotor stimulant, which can be abused in sport to improve endurance, to increase the heart rate, blood pressure, and the release of glucose as well as the adrenaline into the blood. Moreover the effects of nicotine on human body such as marked decrease in stress, increased alertness, improvement in cognitive function, and the reduction of body weight are considered desirable by sportsmen. Although the professional sport is rather not associated with tobacco use, a significant increase in the consumption of nicotine products such as snuff, chewing tobacco, and snuss has been noted in recent years. The aim of this study was to assess the prevalence of the nicotine use by the athletes in Poland between 2013 and 2018.
The GC-MS quantitative method has been validated and acceptable validation parameters have been achieved (e.g. for nicotine: the LOD of 0.44 ng/mL the LOQ of 1.34 ng/mL; the repeatability of 0,6 – 2,2 % for 50 ng/mL and 0,5 – 1,2 % for 1000 ng/mL; the relative bias of 0,94 – 3,75 % for 1000 ng/mL; for cotinine: the LOD of 7,64 ng/mL the LOQ of 22,19 ng/mL; the repeatability of 0,5 – 3,7 % for 50 ng/mL and 0,3 – 2,6 % for 1000 ng/mL; the relative bias of 1,54 – 3,72 % for 1000 ng/mL). The presented method has been successfully applied to the routine analysis of urine samples collected during the anti-doping controls.
Our studies showed that more than 17% of all analyzed in competition samples were tested positive for nicotine or cotinine above the concentration of 50 ng・mL-1 indicating the active consumption nicotine-containing products. Nicotine were detected in 2133 (21,3%) out of 10006 analyzed urine samples collected during the competition (2013: 21,3%, n=1850; 2014: 19,4%, n= 1474; 2015: 14,1%, n=1466; 2016: 20,5%, n=1629; 2017: 23,5%, n=1982; 2018: 28,5%, n=1605). Moreover, nicotine was the most frequently detected in urine samples collected from athletes practicing: athletics, ice hockey, football, handball, volleyball, and weightlifting. The highest concentration of nicotine was detected in urine samples collected from athletes practicing: volleyball, wrestling, weightlifting ice hockey, and motorcycle racing.
We present the development and validation of a sensitive method for the reliable determination of sixteen polycyclic aromatic hydrocarbons (PAHs) in saliva samples, which can be used as exposure markers. This method was based on a liquid-liquid extraction and programmed temperature vaporizer-gas chromatography-mass spectrometry analysis (LLE-PTV-GC-MS). Since no matrix effect was found, quantification was performed using external calibration. The detection limits were lower than or equal to 0.057 μg L−1 for all analytes, and repeatability and reproducibility (relative standard deviation, RSD) were always lower than or equal to 11 and 19 %, respectively. The method was used to quantify polycyclic aromatic hydrocarbons in the saliva samples taken from firefighters and unexposed volunteers, detecting the presence of seven of the sixteen analytes analysed.Two of the compounds (fluorene and phenanthrene) were found in the both exposed and unexposed individuals, while the remaining five analytes (naphthalene, acenaphthylene, anthracene, fluoranthene and pyrene) were only detected in samples taken from the firefighters. Good discrimination between the firefighters and the unexposed volunteers was obtained through a principal component analysis.
A sensitive method for quantification of polycyclic aromatic hydrocarbons (PAHs) in saliva samples is proposed. The method is based on the use of microextraction by packed sorbents (MEPS), injection with programmable temperature vaporizer (PTV), gas chromatography (GC) and mass spectrometry with a single quadrupole (qMS). As far as we know, the MEPS technique has not been used to date for the analysis of PAHs in saliva samples
Due to the matrix effect found with ultrapure water and between different saliva samples, standard addition was used as a calibration strategy. Nine saliva samples were analyzed and phenanthrene was found (15 ± 6 ng L⁻¹) in one of them. To confirm the accuracy of the method, the concentrations added in the standard additions were compared with the value predicted by the calibration model. The values were ranged between 78 and 123 %. The detection limits found in saliva samples ranged between 5 and 79 ng L-1 and the repeatability and reproducibility were always lower than 10 and 16 %, respectively.
The main advantage of the proposed methodology over the existing ones is the complete automation of the analysis process (extraction, separation and detection). Once the saliva sample is placed in the vial, the entire process occurs on-line. It should also be highlighted that the only sample treatment carried out is a centrifugation and filtering of the saliva sample that is subjected to the MEPS process without dilution step.
Amino acids have been of great interest in clinical studies since variation in their concentration may provide information about different disorders. For the first time, a non-separative method based on single quadrupole mass spectrometry (qMS) for the simultaneous semiquantitative determination of sixteen amino acids in saliva samples has been developed. The method includes derivatisation of amino acids with ethyl chloroformate-pyridine-ethanol to obtain volatile products, liquid-liquid extraction (LLE) and further analysis using a programmed temperature vaporizer (PTV) coupled to qMS. This method could be applied to the analysis of a great number of saliva samples, limiting the use of separative methods only when abnormal concentrations of amino acids were found, reducing analysis time and cost. The results obtained in the determination of amino acids using the non-separative were compared to those obtained when a separative method based on gas chromatography (GC) was used, providing values of average relative predictive error (E %) ranging between 2 and 48 %. Repeatability and reproducibility were tested, obtaining relative standard deviation (RSD) values equal to or lower than 11 % and 16 %, respectively. Detection limits were in the range of 0.076-8.747 mg L-1 for the non-separative method. The use of simple instrumentation, as is the single quadrupole mass spectrometer followed by chemometrics, instead of equipment based on high-resolution mass spectrometers or tandem mass spectrometry makes the method applicable in common laboratories all over the world.
Multiple evidences have been reported regarding the role of hormones in different kinds of cancer. Relative concentrations of these analytes in urine can be used as risk biomarkers for cancer.
Urine is a relatively complex matrix from an analytical point of view, consequently mostly of analysis procedures require to isolate the compounds of interest using extraction and concentration steps, together with instrumental techniques that allow the detection of these contaminants, that are generally found at very low concentration levels.
Rotating disk sorptive extraction (RDSE) is a microextraction technique based on equilibrium rather than an exhaustive extraction technique. This technology employs a small rotating disk-extraction device (1.5 cm diameter), which allows to evaluate different sorptive phases easily and at low cost, to select the one that provide the best affinity with the analytes.
In this study, an extraction methodology of 11 hormones (progesterone, testosterone, estrone, estradiol, ethinylestradiol, estriol and the hydroxylated metabolites 2-hydroxyestrone, 4-hydroxyestrone, 16-hydroxyestrone, 2-hydroxyestradiol and 4-hydroxyestradiol) was developed, using RDSE to extract and concentrate the analytes from urine samples which were subsequently determined using liquid chromatography coupled to mass spectrometry (UPLC-TOF/MS). Styrene-divinylbenzene (S-DVB) and OASIS HLB were used as a sorptive phase. After optimization, the methodology was validated considering both phases. The optimal extraction conditions were: 2 mL of sample, diluted with 20 mL of ascorbic acid 0.05%, w / v, and an extraction time 60 min at 2000 rpm of rotation velocity.
The central problem was the interference of the urine pigments (v.e. urobiline), which are strongly retained together with the analytes in both S-DVB and HLB. To avoid the presence of these pigments in the final extract, two alternatives clean up steps were studied and successfully implemented. (a) Dispersive solid phase extraction using primary secondary amine (PSA). The optimal clean up condition was to disperse 300 mg of PSA in the sample simultaneously with the RDSE process. (b) The second clean up alternative was implemented after the RDSE process, which allows a selective desorption of the pigments from the phase, previous the elution of the analytes. In this case a previous desorption was performed using 10 mL of a mixture methanol/water (1:9 v/v), and the final desorption of the analytes was with methanol/ethyl acetate (1:1).
The optimized methodology showed a linear behavior in the range between 0.5 and 10 μg/L, with R2 values between 0.9920 and 0.9989. The analytes are extracted in both phases with absolute recoveries over 70% and RSD between 2 and 10%. The labeled estrogen (20,21) -13C2EE2 was used as a surrogate standard for quantification.
The authors thank to FONDECYT (Project 1180742) for financial support.
Currently there is a great interest in the determination of compounds of clinical significance in biological matrices involving non-invasive methods of sample collection. The use of this kind of matrices (such as urine, sweat or saliva) avoids patient suffering. Hence, in this work, we have developed a high performance method for the determination, by means of a screening-confirmation approach, of polar endogenous compounds (polyamines and related compounds) in urine samples.
In order to perform the analysis, the screening step is carried out using a non-separative method by flow injection analysis coupled to a triple quadrupole mass spectrometer (FIA-QqQ-MS), while the confirmation step is carried out using a separative method by means of a liquid chromatographic system coupled to the aforementioned MS system (HPLC-QqQ-MS). The change from one to another is done using a six port valve, which implies that it is no need for instrumental configuration to be modified.
In order to optimize the methodology, several parameters have been evaluated. First, different urine treatment conditions were studied, selecting the following ones as optimum: freeze the sample at -26ºC, thaw at room temperature, centrifuge at 4500 rpm during 10 min, filter the supernatant and dilute it. Then, an evaluation of possible isobaric compounds in urine samples that could interfere with the target analytes was performed. Next, different parameters regarding the separative method were optimized, such as the chromatographic conditions and the selection of unique MRM transitions, among others. After that, different experimental parameters of the non-separative method were optimized. The possibility of modifying the connection to the MS, using a RAM cartridge or a guard column (C18), was studied in order to increase the sensitivity of the analysis. Also, different dilution conditions were studied with the aim of improving both the sensibility and the morphology of the peaks obtained for the different compounds. Finally, once the optimal parameters for both methodologies (separative and non-separative) were selected, a validation step was performed in order to evaluate the applicability of the proposed strategy.
The methodology was applied to the analysis of urine samples from non-diagnosed subjects. In the first place, the non-separative method was used and subsequently the results obtained by this modality were confirmed with the HPLC-QqQ method.
The main advantage of the proposed methodology is that for the screening step no prior chromatographic separation is required, which allows an increase of the number of samples analyzed per hour. Only suspicious samples, with increased concentrations of the target compounds, are analyzed using of time-consuming chromatographic separation.
Polyamines are ubiquitous aliphatic amines with low molecular weight, which play a critical role in many mammalian processes, such as DNA synthesis and stability, transcription and ion channel regulation, and protein phosphorylation (Koda, 2011). These compounds have long been associated with cell proliferation and tissue growth, and are known to be involved in the development of several tissue types. The association of increased polyamine synthesis with cell growth and cancer was first reported in the late 1960s. However, their use as cancer biomarkers remains controversial. Variations in polyamine levels have also been reported in diseases such as cystic fibrosis, muscular dystrophy or rheumatoid arthritis (Khuhawar and Qureshi, 2011).
Liquid chromatography (LC) methods have primarily been used for the determination of these compounds in biological samples, although other techniques have also been proposed. In most cases analysis has been based on the detection of different derivatives following pre or post-column derivatization (Tsutsui, 2013). When gas chromatography (GC) is used for the analysis of these compounds, a derivatization reaction is mandatory because of their polarity and volatility (Casas Ferreira et al, 2016).
The aim of the present work is to develop a method for the determination of polyamines in urine samples. The approach is based on the study of the new strategies of derivatization based on the use of ketones as derivatizing agents. Following derivatization, reaction products are extracted using ethyl acetate, and the extract is injected (direct injection, DI) into a GC–MS using a programmed temperature vaporizer (PTV) as the injection device. To the best of our knowledge, this is the first time that this approach (DER-DI-PTV-GC–MS) has been proposed for the determination of polyamines in urine samples.
The experimental development of the procedure involves the optimization of the variables that affect the derivatization process: amount of reagent, pH, temperature and reaction time. All the variables that affect the extraction process of the derivatives (type of solvent and volume), the injection (type of liner, temperature and time of venting and injection volume) and separation and chromatographic detection have been optimized..In this sense, the use of a PTV, operating in the solvent-vent mode, allows the injection of large volumes improving the overall sensitivity of the process.
In the optimized experimental conditions the analytical characteristics of the method were evaluated and the determination of polyamines in urine samples was carried out.
Casas Ferreira, A. M., Moreno Cordero, B., Crisolino Pozas, A. P., Pérez Pavón J.L. (2016). J. of Chromatogr. A, 1444, 32-41.
Khuhawar, M., Qureshi, G. (2001). J. Chromatogr. B, 764, 385-407.
Soda, K. (2011). J. Exp.Clin. Canc. Res., 30, 95-104.
Tsutsui, H., Mochizuki, T., Inoue, K., Toyama, T., Yoshimoto, N., Endo, N., Todoroki, K., Min, J.Z., Toyo’oka, T. (2013) Anal. Chem., 85, 11835-11842.
Doping control in sport is conducted by the WADA-accredited anti-doping laboratories that analyze human doping control samples in order to detect substances prohibited in sport. Due to the complexity of the urine matrix that contains inorganic salts, organic compounds such as proteins, hormones and a wide range of metabolites depending of what is introduced into the body, it is important to minimize its impact on the obtained results of the analyzes and their proper interpretation. The urine samples collected from athletes during doping controls undergo a complex and multi-stage sample preparation prior to the analysis using either GC/MS system or, starting from 2011, GC/MS/MS system.
Tetrahydrocannabinol (THC), or more precisely its main isomer (−)-Trans-Δ9-tetrahydrocannabinol, is the principal psychoactive constituent of the cannabis plant. Tetrahydrocannabinol can be used in sport to improve endurance as it causes a marked decrease in stress. Additionally, it has anticonvulsant and analgesic properties. Small doses of THC in addicted athletes can cause euphoria, bliss, and at the same time reduce both intellectual and physical abilities. In 2004, the active metabolite of THC (Carboxy-THC) was officially classified as a doping substance in the competition in concentrations above 15 ng/ml. In May 2013, the World Anti-Doping Agency increased the acceptable concentration of Carboxy-THC from 15 to 150 ng/ml.
In Polish Anti-Doping Laboratory two methods, using GC/MS/MS and GC/MS systems, have been developed to determinate the concentration of Carboxy-THC in analyzed urine samples. The first method is the routine method for the detection of not only Carboxy-THC, but also the anabolic-androgenic steroids. The second method is devoted to the quantification of Carboxy-THC concentration in samples that were reported as positive for Carboxy-THC based on the routine analysis.
The aim of this study was to show the impact of the change of the decision threshold on the use of this substance by Polish athletes. Retrospective evaluation of the results of a routine anti-doping testing was performed for the period from 2009 to 2018. Urine samples collected during the anti-doping control were tested for the presence of Carboxy-THC by means of gas chromatography combined with mass spectrometry (GC/MS, GC/MS/MS). In this approach Carboxy-THC was detected in 1128 (4.4%) out of 25791 analyzed urine samples (2009: 1.7%, n=2637; 2010: 1.45%, n=2689; 2011: 1.97%, n=2691; 2012: 3.2%, n=2718, 2013: 5.6% n=3224, 2014: 7.2% 2800, 2015: 6.3% n=2654, 2016: 6% n=2788 and only in competition: 2017: 5.2% n=1982, 2018: 5.5% n=1608 ).
The consumption of THC during the out-of-competition periods increased drastically from 1% in 2009 to 9.1% in 2014 and about 7.2% in 2013, 2015 and 2016. Additionally, the concentration of Carboxy-THC in analyzed samples rose after the WADA increased the allowed concentration of carboxy-THC in urine. Similar situation presented itself in samples collected in-competition. The number of positive samples increased from 1.2% in 2010 to 5.4% in 2014 and it has been stable until now.
1) A. Pokrywka, R. Grucza: Marihuana w sporcie. Medycyna sportowa 2006
2) WADA Technical Document – TD2019DL
Selective androgen receptor modulators (SARMs) were developed as a treatment of choice for diseases such as muscle-wasting, breast cancer, and osteoporosis which are currently cured with steroidal androgens. The main advantage of SARMs over endogenous compounds results from higher tissue-selectivity . Owing to their mechanism of action, high potency combined with a significant reduction of adverse side-effects, SARMs are often considered as successors of anabolic agents, the most frequently detected class of drugs misused by the athletes for over three decades. Hence, in 2008 the World Anti-doping Agency (WADA) prohibited their application by sportsmen .
Nevertheless, the demand for new doping agents among athletes grew stronger. Regardless of the fact that only Ostarine reached the III phase of clinical trials, over one hundred of samples have already been reported positive for the presence of SARMs. Additionally, the compounds were recurrently seized by customs and owing to the FDA investigations, some dietary supplements containing Ostarine and Andarine were recalled from the market.
The aim of presented study was to determine the main metabolites of four structurally unrelated SARMs, namely: BMS 564929, GSK 2881078, PF 06260414, and TFM-4-AS-1. Although the compounds are undergoing different phases of preclinical or clinical trials, they are already available in online stores. Thus, routine analytical methods used in doping control analysis should involve screening for those compounds and/or their metabolites.
Within the presented study, the metabolites were synthesized with the use of two human liver fractions – the microsomes (to investigate I phase metabolism) and the S9 fraction (in order to obtain both I and II phase metabolites). In pursuance of gathering as wide spectrum of metabolites as possible, a few alterations of standard protocol were used. Moreover, three different sample preparation procedures were tested to minimize the analytes’ loss.
The identification of products and development of the analytical method (validated according to WADA technical documents) were carried out on two different LC-HRMS/MS systems. The first step was performed using an Ultimate 3000 RLSCnano system (Thermo Scientific Dionex) combined with an Orbitrap Tribrid Fusion mass spectrometer (Thermo Scientific), while the second involved a Vanquish UHPLC system combined with an Q-Exactive mass spectrometer (Thermo Scientific).
Finally, the metabolites, mainly resulting from a single or multiple hydroxylation, methoxylation, or the combination of both reactions, and the following II phase modifications, were discussed as potential markers for doping control analysis.
Presented study was conducted as a part of the research project founded by the National Science Centre of Poland (grant No. 2015/17/N/ST4/03923). Part of the study was carried out at the Biological and Chemical Research Centre, University of Warsaw established within the project co-financed by European Union from the European Regional Development Fund under the Operational Programme Innovative Economy 2007–2013.The financial support of the Ministry of Science and Higher Education of Poland (Agreement No. 6844/IA/SN/2018) is also greatly appreciated.
1) R. Narayanan, C.C. Coss, J.T. Dalton. Development of Selective Androgen Receptor Modulators (SARMs), Mol Cell Endocrinol. (2018), 465: 134–142.
2) WADA, 2019 List of Prohibited Substances and Methods, available at: https://www.wada-ama.org/en/resources/science-medicine/prohibited-list-documents.
Flavonoids are group of secondary plant metabolites, derivatives of phenylchromone. They differentiate based on the structure of the dihydropyron ring and hydroxylation and subsequent methylation and glycosylation. Humans are exposed to flavonoid through everyday diets; fruits and vegetables present rich sources of flavonoids. Many of them have beneficial effects on health that include antibacterial, antiviral, hepatoprotective, antithrombotic, anti-inflammatory, etc. When ingested, flavonoids usually undergo hydrolysis of sugar moieties and are absorbed as aglycones. These aglycones are metabolized in liver and one of the major enzymes involved in their biotransformation is cytochrome P450 1A2 (CYP1A2). In this study objective was to determine inhibitory effect of flavonoids on CYP1A2.
Study was conducted on 30 flavonoids most commonly found in Croatian medicinal plants. All flavonoids were used in 1 µM concentration. Inhibition was determined using O-deethylation of phenacetine as a marker reaction. Reaction mixture was monitored by reverse phase high performance liquid chromatography coupled with diode array detection.
In case of metabolic inhibition assay chrysin was the strongest inhibitor decreasing enzyme activity by 82% (P = 0.004), followed by morine 61% (P = 0.025), and hesperetin 45% (P = 0,029). However, majority of the observed inhibition in metabolic inhibition assay is consequence of direct inhibition. In direct inhibition, other strong inhibitors were morin, isorhamnetin, pinocembrin and hesperetin. As there was no statistically significant difference between direct and time-dependent inhibition, it can be concluded that majority of inhibition comes from direct inhibition of enzyme e.g. competition with a substrate.
Parkinson’s disease (PD) is the second neurodegenerative disorder after Alzheimer disease. It is a multifactorial disorder caused by aging, environmental and genetic factors.
We aimed to explore biomarkers profiles for ageing, in order to study the mechanisms involved in the pathogenesis of the disease.
We report a metabolomic profiling of a 54 PD Tunisian patients (27 men, and 27 women) with a mean age of 65.35±10.30and an average weight of 70.26±10.14 and mean Hoehn&Yahr (HY) 2±1, treated with Levodopa, using a gas chromatography-mass spectrometry (GC-MS) technique.
We analyzed a total of 63 metabolites and 92 unknown metabolites. Many of the identified metabolites are considered as metabolic fingerprints characteristic for PD. These metabolites represent key metabolic pathways related to oxidative stress, mitochondrial dysfunction, alterations in alanine branched-chain amino acids, fatty acid metabolism, aromatic amino acids and purine pathway.
The specific molecular feature of biomarkers can be helpful to understand the physiologic process of the PD. Our findings clearly demonstrated that mitochondrial dysfunction and oxidative stress could be the main factor in the onset of PD.
Angiotensin-II receptor antagonists with diuretics are mainly used in the treatment of hypertension and combined usage of them is listed in the Prohibited List of WADA. In this study, a capillary zone electrophoretic (CE) method was developed for the determination of hydrochlorothiazide (HCT), irbesartan (IRB), telmisartan (TEL) and valsartan (VAL) with diode array detection (DAD). After method validation, the CE-DAD method was applied to biological samples. A 40 cm effective length (48.5 cm total, 50 µm i.d.) fused silica capillary was used to separate the compounds. The related compounds were detected at 230 nm wavelength. The run buffer was 15 mM borate buffer containing 10% methanol (pH 9.0). The samples were injected for 10 s under 50 mbar pressure and the applied potential was 25 kV. Candesartan was used as internal standard (IS). Under these optimum conditions total run time was less than 7 minutes. The method was validated using spiked plasma samples according to official recommendation of ICH.
For the application of the method, plasma samples were collected from rats. The plasma samples were prepared and analyzed in accordance with CE-DAD system. The application of the method was successfully demonstrated for real rat plasma samples.
This study was carried out to evaluate the healing activity of autologous PRP by its topical application to the skin experimentally injured in a sheep model. In order to appreciate a reliable protocol for the production of autologous PRP in sheep, we have proceeded by a comparative study between four different methods of preparation. The results obtained showed that the mean number of platelets in whole blood was 521.56 ± 97.01 x 103 / μl. Group I and III PRP samples showed significantly higher mean platelet counts compared to Groups II and IV (1438.25 ± 221.72 × 103 / μL and 1430.75 ± 293.63 × 103 / μL)., respectively). It therefore appears that the group I PRP revealed the highest platelet mean number in comparison with the other groups. To evaluate its healing activity, full-thickness incision wounds, and complete excisional wounds of the skin were created on the back of each animal. The animals were randomly divided into 3 equal groups of 3 sheep for each. In group I, wounds were treated with PRP, in group II wounds were treated with Asiaticoside and in group III wounds were treated with saline. The different treatments were administered topically at an interval of 3 days. Morphometric measurements of the contraction surface of the wounds and histopathological biopsies were performed on the 3rd, 7th, 14th, 21st and 28th day of healing. The morphometric results obtained show that it had significant differences recorded on the 7th and 14th day of healing in favor of group I animals. Semi-quantitative histopathological evaluation showed that PRP reduces inflammation during the first 3 days post -surgical, and promotes epithelialization in 3 weeks of healing.
A rapid, simple and sensitivity method for the determination of fluoxetine and norfluoxetine enantiomers using Ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) coupled with field-amplified sample sacking (FASS) in capillary electrophoresis was developed. Sensitivity parameters that affect the efficiency of the extraction in UA-DLLME and preconcentration by FASS. Such as the kind and volume of extraction and disperser solvents, extraction time, addition of salt, and efficiency of FASS were investigated and optimized. Under optimum extraction and stacking conditions, the enrichment factor were obtained in the range from 2000-2800. The linearity of the method for fluoxetine enantiomers was in the range of 0.4-150 nM and for norfluoxetine enantiomers was in the range of 0.5-150 nM. with correlation coefficient (r2) greater than or equal to 0.9968 and relative standard deviations of the peak area analysis were in the range of 5.1%–5.3% (n = 5). The Limits of detection at a signal-to-noise ratio of 3 ranged from 0.12 to 0.17 nM. The relative recovery of fluoxetine and norfluoxetine enantiomers from urine and serum were in the range of 97.4%–107.2% and 97.5%–106.1%, respectively. The findings of this study show that UA-DLLME-FASS in capillary electrophoresis has demonstrated to be rapid, sensitivity and convenient method for identifying fluoxetine and norfluoxetine enantiomers in urine and serum.
Hops, the typical female organs of the hops plant (Humulus lupulus L.), is rich in secondary metabolites, (xanthohumol, isoxanthohumol, α-acids and β-acids, etc). These compounds are key as beer ingredients, since they impart their flavor (bitterness and hop flavor), greater foam stability and bacteriostatic activity. Additionally, the products derived from hops are used in alternative medicine for insomnia, anti-inflammatory and estrogenic ailments. In Valdivia, southern Chile there are several wild ecotypes of hops growing freely since the German pilgrims came to Chile and brought their hops plants to brew beer before the 1900s.
Due to the importance of hops to the Valdivian Province, we have studied six wild hops from the Valdivian region to find out the nutritional values, mineral and phenolic content and antioxidant properties and compared them with genetically modified varieties from other regions, such as Argentinean, German and American varieties. We have also manufactured a hop nutraceutical supplement with a selected ecotype and quantified the amount of bioactive phenolics.
Tangeretin is a flavonoid found in citrus plants. Structurally, it presents an O-polymethoxylated derivative of flavone. It has been extensively studied due to the possible beneficial effects on human health that include neuroprotective, anti-inflammatory, antiasthmatic, antidiabetic, anticancer and other properties. Although metabolism and pharmacokinetics of tangeretin has been studied, due to numerous metabolic products, not all metabolic reactions of tangeretin have been well characterized.
Thus, the objective of this work was to characterize tangeretin metabolism mediated by cytochromes P450. For this purpose, human liver microsomes (HLM) and recombinant cytochrome P450 enzymes were used. Metabolism was monitored by liquid chromatography coupled with mass spectrometry (electron spray ionization, time of flight detection) for metabolites determination and diode array detector for quantification.
Tangeretin generated more than 10 metabolites in the incubations with HLM. The largest number of detected metabolites refers to single and double demethylated tangeretin derivatives in various combinations and at different positions on the rings A and B. Two major metabolites, most commonly found in tangeretin incubations with HLM, were indirectly identified based on data obtained by LC-MS/MS analysis. MS/MS spectra showed a loss of -14.01564 Da on the ring B with the retention time of 9.52 min. Since only one methoxy group at position 4' is present in the tangeretin ring structure B, this metabolite was characterized as a 4'-demethylated tangeretin derivative, i.e., 4'-hydroxy-5,6,7,8-tetramethoxyflavone. Similarly, the structure of the second most commonly found metabolite detected at 7.83 min showed a mass increase of 1.9799 Da on the ring B, indicating demethylation at the 4' position and hydroxylation at the positions 3' and the formation of 3',4'-dihydroxy-5,6,7,8-tetramethoxyflavone.
Tangeretin metabolism was mediated by CYP1A2, CYP2D6, and CYP3A4 enzymes. Based on the amount of metabolite produced, it can be concluded that the most important enzymes are CYP1A2 and CYP3A4.
Total phenolic content, flavonoid concentration and antioxidant activity were determined by spectrophotometric methods in Teucrium flavum extracts. Water methanolic, ethyl acetate and aqueous extract were analyzed. The concentration of total phenolic compounds was determined by Folin-Ciocalteu reagent and the obtained values ranged from 157.45 to 189.38 mg EAG/g of extract. The concentrations of flavonoids in plant extracts of T. flavum ranged from 3.20 to 5.24 mg EQ/g of extract. The evaluation of antioxidant capacity by the method of free radical scavenging test showed that all of the extracts have a very good reductive activity, especially for ethyl acetate extract which presented a percentage of inhibition equal to 90% with an IC50 estimated to 12.76 ug/ml. On the other hand, the FRAP test and β-carotene bleaching method revealed that the aqueous extract has the best reducing power than those of the other extracts, but it remains relatively low compared to the ascorbic acid used as positive control. The obtained values show that some extracts of T. flavum are very rich source of phenolic compounds with strong antioxidant activity. The extract of T. flavum, could be considered as a source of potential antioxidants and will promote the reasonable usage of these plants in food technology and processing as well as for medical use.
Keywords: antioxidant activity. Total phenolic content, Total flavonoid content. DPPH
Surface-enhanced Raman scattering (SERS) spectroscopy was applied to study binding of natural alkaloid molecules, berberine and sanguinarine, with G-quadruplex (G4) DNA structure. The antiparallel “basket” type G4 structure was obtained upon annealing the human telomeric sequence d[TTAGGG]₄ (Tel24) in presence of sodium ions. In addition, the alkaloids selectivity for four-stranded over double-stranded DNA was investigated using calf thymus (ct) DNA. The SERS spectra of the alkaloid ligands, the DNA structures and their complexes in the [ligand]/[DNA] molar ratio of 1/1, 1/3 and 1/6 were acquired upon NIR excitation in a citrate-reduced silver colloid aggregated with sodium sulfate.
The same slight decrease in the SERS intensity of berberine bands, regardless of the [ligand]/[ct-DNA] molar ratio, implied very weak interactions with ct-DNA, associated with structurally nonspecific binding of the berberine molecules along the phosphate helix. Moreover, the SERS spectra of sanguinarine with ct-DNA resembled the spectrum of the ligand alone, not indicating any interactions of the sanguinarine molecules with the nucleic acid. On the other hand, notable spectral changes were observed for the complexes of the alkaloid molecules with G-quadruplex, particularly pronounced for the complexes of the [ligand]/[G4] molar ratio 1/3. While significant diminution in the overall SERS intensity indicated stacking of the berberine molecules onto the G4 structure, the upward shift of the guanine bands implied interactions of the sanguinarine molecules with the G4 grooves. The observed SERS spectra clearly pointed to different binding modes of berberine and sanguinarine with antiparallel G-quadruplex as well as to higher affinity of both alkaloid molecules for G-quadruplex over duplex DNA.
Conventional cigarette butts are the single most collected item in annual international coastal and urban clean-ups. Once dumped, they move through sewer systems and streams into the oceans and/or accumulate in localized areas. Environmental awareness on the disposal of tobacco products (TPs) mainly focuses on the inability of discarded filters to biodegrade. There is markedly less awareness on the potential of TPs to act as point sources and leach chemicals. To this end, past studies have found cigarette litter toxic to some aquatic species. At the same time, a novel ‘heat-not-burn’ TP was introduced that is becoming increasingly popular. The impact of disposing and exposing them to environmental water bodies is unknown. The present work aims to determine the inorganic components (Al, As, Ba, Cd, Cr, Cu, Hg, Ni, Pb, Se and Zn) and nicotine leached from heated tobacco sticks and conventional cigarettes in water. Two types of tobacco sticks (non-Aluminum and Aluminum versions) and one brand of conventional cigarettes were studied. Leaching from used and unused TPs into deionized water was initially considered. The resulting dissolved concentrations were compared to the total content of each metal and nicotine in used and unused solid TPs. Almost all metals were detected in leachates shortly after TP addition and almost all metal concentrations reached near-equilibrium conditions after 1 day of leaching. Arsenic was the only metal not detected in solid TPs (total concentrations) and leachates (dissolved concentrations) from used and unused TPs. Within 1 day of leaching, the dissolved concentrations of Hg and Pb were below the limits of detection of the method. The highest fractions of metals leached in water were recorded for Zn, Cu and Se. The total content of nicotine found in solid TPs was released into the aqueous phase after 1 day of soaking, reaching in all cases dissolved concentrations that exceeded the predicted no effect concentration under the set experimental conditions. The dissolved concentrations found in leachates from unused TPs were, for the majority of metals studied here and for nicotine, larger than those found from used TPs. The contribution of the different parts of TPs (i.e., filter, tobacco and paper) to the inorganic and nicotine content of leachates was assessed for used and unused TPs. Tobacco was the major source of metals for both the dissolved and total concentrations. Nicotine was only found only in tobacco in unused TPs whereas after smoking, the paper and filter also contributed to total and dissolved concentrations of nicotine. The effects of varying pH, salt and humic acids on the leaching behavior of metals and nicotine from TPs was also studied, next to the effect of matrix where rainwater, river water and seawater were used to leach from used and unused TPs. In all cases, the leaching behavior was similar to that in ultra-pure water Discarded TPs may look like the end point of a life cycle, but there is still a way to go in addressing post-consumer waste clean-up and responsible disposal.
In human body, numerous critical functions in cells and organs are dominated by electric signals. It has been established that electric potentials stimulate the distinct effect on distinct cells and can direct the movement and migration of cell types including corneal, epidermal and epithelial. Piezoelectric nanotransducers have ability to generate electric potential on their surfaces due to their piezoelectric virtue when exposed to mechanical force. Piezoelectric nanomaterials such as barium titanates (BaTiO3) and boron nitride nanotubes (BNNTs) are promising in biomedical applications especially for the stimulation of electrically responsive cells including nervous, cardiomyocytes, skeletal myotubes and osteoblasts. While preferring a nanomaterial for piezoelectric stimulation in medical use their mechano-electrical transduction (piezoelectric coefficient, d), the biocompatibility level, purity of the material, and the availability (synthesizable or commercially available) criteria must be taken into consideration. In this study, a novel piezoelectric composite which include both BNNT and BaTiO3 was synthesized in order to provide indirect electrical stimulation under low frequency ultrasound stimulation (US) to hOBs (human osteoblast cells). The piezoelectric feature of the synthesized composite was evaluated using piezo response force microscopy (PFM). The concentrations to be used in US stimulation studies were identified based on minimum cytotoxic and maximum uptake doses on hOBs. Osteoblastic function and maturation during US were investigated through assaying osteogenic markers such as osteopontin (OPN), alkaline phosphatase, osteocalcin (OCN) and assessing the mineral matrix’s quantity and morphology. This composite have been expected to be a powerful candidate to nanotransducer class due to its dual piezoelectric effect and will provide an advantage for the treatment of bone diseases.
Nanomaterials have unique optical, physical, chemical and biological properties when compared to their bulk form. These unique properties of nanomaterials are controlled by quantum mechanics rather than classical physics.
To use nanomaterials in biological applications including medicine, it is important to understand their interactions with biological structures ranging from small biomolecules to cells and tissues. For this, several techniques are employed including molecular and spectroscopic. Among many techniques, Raman spectroscopy is a powerful vibrational technique that can provide information not only about the interaction of nanomaterials with biological structures but also about the intracellular structures and pathways in a non-invasive and label-free way. The use of noble nanostructured metals, gold and silver, to enhance the Raman scattering is a unique opportunity to gather molecular information surrounding them in a complex biological environment. The technique is a nonlinear form of Raman spectroscopy and named as surface enhanced Raman spectroscopy (SERS).
In this study, endosomal pathway of AuNPs is investigated using SERS. To investigate the different types of endocytosis; specific inhibitors for each endocytosis type is used. Sodium azide is used for the ATP depletion; sucrose and chlorpromazine are used to inhibit the clathrin mediated endocytosis; nystatin is used to inhibit the caveolae mediated endocytosis and dynasore are used to inhibit the dynamin dependent endocytosis. Beas-2b (human bronchial epithelial cells) and A549 cells (adenocarcinomic human alveolar basal epithelial cell) are treated with the inhibitors for 2 hours and then with the AuNPs for 24 hours. To understand the uptake and inhibition of uptake of AuNPs, flow cytometry is used. SERS spectra are obtained from living cells after treatment of both inhibitors and AuNPs. From the obtained spectra, it is found that endosomal entry preference of AuNPs can be deduced and spectral changes according to the different type of endocytosis can be obtained by SERS.
Pearl Millet (Pennisetum glaucum (L.) R. Br) is a very important cereal mainly used in Africa and India, it has an interesting nutritional content reaching 65% starch and 16% protein (on dry basis), and can resist to the difficult arid Sahara conditions such as saline soils and unpredictable rain. This study aims to value and exploit Algerian Pearl Millet through the extraction of grains starch by both conventional wet milling method (in presence of a microbial growth inhibitor) and Ultrasound method. Extracted starches were considered in terms of yield, recovery, chemical composition, and other physical properties to estimate the efficiency of the extraction method. The ultrasound extraction method gave enhanced yields and recoveries, and higher starch purity, with ranges of (30 - 52 %), (46 - 75 %), and (91 - 94 %) respectively, all this in a short period of time without generating any alkaline waste. These results are expected to be helpful in the production of starch from Pearl Millet in Algeria, where this cereal is considered as a low cost and a high nutritious source.
In this study were established a fast and effective method to identify biological volatile organic compounds in antagonistic bacteria’s against fire blight, including Bacillus amyloliquefaciens, Pantoe agglomerans and Pseudomonas fluorescens by solid-phase microextraction (SPME) coupled with gas chromatography mass spectrometry (GC/MS). A novel approach was applied to reveal the relationship between the profile of biological volatile organic compounds and the relevant bacterium. The established method was successfully applied to identification of the five antagonistic bacteria. HS-SPME provides an efficient and non-invasive method for sampling a wide range of volatile compounds emerged from bacteria. Five commercial SPME fibers were applied for the sampling of bacterial VOCs released from antagonistic bacteria’s against fire blight when proliferated in different culture media. The effect of fiber coating was fully investigated. The results revealed that the CAR/PDMS fiber can absorb the highest number and amount of volatile compounds. Various volatile compounds such as esters, hydrocarbons, alcohols, ketones and aromatic containing species were identified.
Stochastic microsensors based on 2 types of reduced graphene oxide paste and myoglobin used as electroactive material were developed for the assay of luteinizing hormone (LH), and follicle stimulating hormone (FSH) in children’s saliva. During pre-pubertal age, levels of gonadotropins are low or undetectable, but rising when puberty starts to set. Precocious puberty occurs due to a hormonal unbalance that happens when the secretion of LH and FSH is not inhibited anymore, so the levels of these two hormones are getting higher than during childhood period
The two types of reduced graphene oxide powders are: a sulphur-reduced graphene oxide powder (commercial type) and a silver-reduced graphene-oxide nanocomposite powder (synthesized in the lab). SEM, TEM and XRD measurements were done for topographical characterization of the synthesized material.
The advantage of using such tools is the possibility to identify and quantify both hormones within minutes in small volumes of childen’s saliva. The good response characteriscs of the porposed stochastic microsensors obtained for LH and FSH made possible the molecular screening of saliva samples from prepubertal children. The main utilization of the proposed stochastic microsensors is to identify earlier problems related to early onset of puberty.
Environmental pollution caused by heavy metals such as lead has detrimental effect on human health. Heavy metals as aqueous pollutants are determined by whole cell microbial biosensors efficiently. For this purpose, the gram negative bacteria was isolated from Eymir Lake in Ankara, Turkey to investigate biosensors potential. The objective of work was the invention of new high sensitive whole cell microbial biosensors to determine heavy metals in aqueous solutions and optimise the working conditions.
The isolated bacteria was grown at nutrient agar plate for 48 hours at 30°C. Bacteria cells were collected from the agar surface and mixed with carbon paste as 1:9 ratios. Modified carbon paste was placed into handmade electrode with 2 mm diameter and used as working electrode. The counter electrode was platinum wire and Ag/AgCl was used as reference electrode. Heavy metal solutions were prepared with Pb(NO₃)₂ and Tris-HCl used as buffer solution at pH:7 at 24°C. All electrochemical experiments were triplicated and performed with CH Instruments 660B model Electrochemical Workstation (CH Instruments USA). The instruments were equipped with conventional three-electrode cell, containing 10 mL lead solution, deoxygenated by passing through pure nitrogen. The study shows that the sensor was found in linear range between 1x10⁻⁵ M and 1x10⁻⁸ M with the lowest detection limit 10⁻⁹ M. The optimum pre-concentration time and scan rate were measured as 10 minutes and 10 mV/s respectively. The results support that the new isolated gram negative bacteria has significant potential to determine lead as ppb level.
NADH (beta nicotinamide adenine dinucleotide, in its reduced form) is the cofactor of a large number of dehydrogenase enzymes and plays an important role in the electron transfer chain in many biological systems. Many enzymatic reactions useful for the manufacture of compounds in the industry are dependent on the reaction of this cofactor, but they require high electrochemical overpotentials to promote the oxidation of NADH. For this reason the use of modified electrodes is the tool most used by many researchers to address the problem of overpotential. However, the modification of electrodes is usually a slow and complicated process that involves the incorporation by covalent bonds of molecules to the surface of the electrodes. In this work, 4-phenylbutyl 3,5-dinitrobenzoate (3,5-DNBP) ) (Fig.1) was used to modify multi walled carbon nanotubes (MWCNT). This nitro compound was activated in the electrode surface generating a redox couple nitroso/hydroxylamine derivatives that acts as mediator for the oxidation of NADH. With this new methodology, the mediator redox couple is in the 3D structure formed by the nanotubes and the modification of the electrode is simple and fast. The use of the electrochemical mediator facilitates the oxidation of NADH obtaining greater current and low overpotentials compared to common electrodes. The measurements were made using differential pulse voltammetry. A 3mM solution of 3,5-DNBP in acetonitrile was used with a modification time of 10 seconds. The concentrations of NADH prepared in buffer B-R 0.1M at pH 7 range from 0.1mM to 0.6mM with an increase of 0.1mM at each point of the curve. Each measurement was made in triplicate. The sensitivity of the calibration curve corresponds to 70.46 [% i↓electrocatalytic / [NADH]] with a Detection limit (LOD) of 22.3 μM and a quantification limit (LOQ) of 74.2 μM.
Catecholamines act as neurotransmitters or hormones at central and peripheral levels and they are involved in the control of arousal, attention, mood, learning, memory, stress response and regulate mood, attention, motivation, sleep-wake cycles, cognition, etc. Abnormal concentrations of catecholamines are also associated with numerous diseases. A precursor to catecholamines is tyrosine, which is transformed to L-DOPA through a series of enzymatic reactions. Further enzymatic conversions are: L-DOPA - dopamine - noradrenaline - adrenaline. For the determination of catecholamines various methods were used, e.g., chromatography, spectrophotometry, flow injection analysis, capillary electrophoresis and electrochemical methods. The aim of this work was to investigate conditions for electrochemical detection of L-DOPA, dopamine, noradrenaline, and adrenaline in a flow system with four mini-reactors filled by mesoporous SiO₂ powders (SBA-15 and MCM-41) with covalently bound enzymes laccase (Lac) and tyrosinase.
Biosensors based on the above mentioned flow enzymatic mini-reactors and a tubular detector of silver solid amalgam as a working electrode were used for amperometric determination of L-DOPA, dopamine, noradrenaline, and adrenaline. Biosensor with Lac-MCM41 reactor proved to be the best one and basic parameters of dopamine determination were studied and optimized for it.
The detection potential is one of the most important parameters for amperometric determinations, influencing both sensitivity and selectivity of measurements. The largest current response was observed between +50 and –50 mV with maximum around 0 mV. These potentials correspond to the reduction of quinone molecules formed during enzymatic reaction.
The dependence of the peak current on the injection volume is approximately linear only at low volumes and then the increase of the current response gradually diminishes. Increasing the flow rate from 0.01 to 0.20 mL min⁻¹ increases the current response 1.9 times.
Reactor volume (Vreactor) affects measurement sensitivity, a reactor lifetime, consumption of enzyme-coated powder, etc. The powder of Lac-MCM41 was used for gradually filling the mini-reactor. The current response increases only to a reactor volume of about 12 μL. Further growth of Vreactor increases the reactor's enzymatic capacity, and hence its lifetime, but also increases a hydrodynamic resistance in the system.
Dependence of the peak current on analyte concentration was measured in the concentration range 0.004 – 0.50 mmol L⁻¹ of dopamine. The linearity is lost at higher concentrations and a linear section ended under used conditions at dopamine concentration 0.2 mmol L⁻¹.
Repeatability and lifetime of the biosensor. Statistical results of parallel determinations of studied analytes with the biosensor have proven its good accuracy (RSD = 1.82 – 5.18 %) and sensitivity (5.46 – 15.5 µmol L⁻¹). The lifetime of the studied biosensor is quite long and it allows determining catecholamines for several months.
A current response of the Lac-MCM41 biosensor was 100 % for dopamine, 32.1 % for L-DOPA, 26.2 % for noradrenaline and 0.71 % for adrenaline.
The biosensor based on the Lac-MCM41 reactor was successfully used for the electrochemical determination of dopamine and noradrenaline in medical solutions for infusions.
This work was financially supported by the Czech Science Foundation (project no. 17-03868S).
Electrochemical immunosensors take a leading position among portable test systems for the rapid determination of bioanalysts. Of particular interest are immunosensors for the diagnosis of oncological diseases (Hasanzadeh & Shadjou, 2017). Addressed covalent immobilization of antibodies improves analytical characteristics, and also opens up broad prospects for automation, miniaturization, and the creation of lab-on-the-chip devices.
The methods of biorthogonal conjugation, for example, the click-chemistry reactions are the most attractive for the immobilization of bioreceptors (Vranken et al., 2017). Such processes are carried out in "soft", i.e. close to physiological conditions, characterized by high speed and yield of products (Kolb; Finn & Sharpless, 2001). In the reactions of azide-alkyne cycloaddition (CuAAC), the catalyst is Cu (I) ions, whose stability is maintained by the introduction of an antioxidant into the reaction medium. The most widely used catalyst systems are CuSO4 / sodium ascorbate (Rostovtsev et al., 2002). The main disadvantage of it is the duration of the process (8-12 hours). To reduce the reaction time, the electrochemical generation of Cu (I) ions from a solution of the Cu (II) salt was used. However, this usually leads to a loss of the immunoreceptor affinity (Lesniewski et al., 2015). The creation of “precursors” on the working electrode surface for latter covalent immobilization of the immunoreceptor allows to simplify the procedure as much as possible and contributes to maintaining the affinity of native antibodies.
The aim of this research are to create a method for addressed covalent immobilization of anti-carcinoembryonic antigen (CEA) antibodies using the CuAAC reaction catalyzed by copper particles incorporated into an electrochemically deposited polymer film on a carbon electrode surface.
According to the nucleophilic substitution reaction, vinyl benzyl azide was synthesized. The structure of the compound was confirmed by IR spectroscopy. The processes of electrodeposition / electropolymerization of vinyl benzyl azide on the carbon electrode surface are investigated. The features of the copper particles formation are studied both in the growing and in preliminarily obtained polymer film on the electrode. The working parameters for electrochemical deposition and electrically dissolving of copper particles from a polymer film were optimized. The successful reaction of the azide-alkyne cycloaddition of propargyl-N-hydroxysuccinimide ester catalyzed by the oxidation products of copper particles has been shown. The obtained original results allowed us to create a method of addressed covalent immobilization of proteins, in particular, anti-CEA antibody on the surface of carbon electrodes.
The proposed method is different by the strength of protein binding, helps to save the affinity of the native receptor, reduces the time, material and labor costs for immobilization, since it does not require prior stage of protein alkylation. All of this will ultimately contribute to improving the sensitivity and accuracy of electrochemical immunoassay.
|Stage||Selected working parameters|
|Electropolymerization VBA||CV from -0,5 to −3,0 V (scan rate of 100 mV/s) for 6 cycles|
|Reaction CuAAC||LV from 0 to −1 V (scan rate of 10 mV/s) for 3 scans|
|Antibody immobilization||30 minutes, room temperature|
|Detection||EIS in 10mM K3[Fe(CN)6]/10mM K4[Fe(CN)6] 0,1 M KCl water solution|
Any deviations in the blood glucose level from the permissible value are a sign of impairment of health, therefore the determination of glucose is one of the most demanded analysis in modern medicine. The currently available methods for the determination of glucose have a number of disadvantages, such as expensive enzymes and equipment, that needs large amounts of analysis. Enzyme biosensors for the determination of glucose have an insufficiently stable response due to changes in the activity of the enzyme over time, and they also lose their activity due to changes in pH, temperature and light. As a consequence, the creation of new highly sensitive, selective and express sensors, which exclude the use of enzymes and other expensive components from the determination of glucose, is required.
Promising methods for solving this problem are electrochemical methods of analysis, in particular, the use of electrocatalysts as sensitive elements of sensors. The use of electrocatalysts based on transition (Ni, Ru etc) and noble (Ag, Pd etc) metals to create sensitive enzymeless receptors is a promising direction in the determination of glucose and another blood components. Carbon nanomaterials (graphene, multiwalled carbon nanotubes (MWCNT) etc) are widely used in sensors construction as electrode modifiers due to their large surface and high electrical conductivity. They contribute to an increase in sensitivity and selectivity compared to a non-modified electrode.
Thus, the purpose of this work was to develop sensitive enzymeless receptors - electrocatalysts based on mixed organic complexes Ni(II)/Ru(III) immobilized on polydopamine/MWCNT, and Pd/Ag nanoparticles immobilized on MWCNT, as electrode modifiers that provide a stable and reproducible analytical signal from electrocatalytic oxidation of glucose.
Studies were performed using a Metrohm Autolab PGSTAT128N potentiostat/galvanostat (Metrohm AG, the Netherlands) and glassy carbon electrodes (GCE). Various electrode modifications with surfactant and MWCNT suspension, polydopamine and Ru(III)/Ni(II) complex in acetylacetone solution, ruthenium (III) chloride solution in acetylacetone, nickel (II) nitrate solution in acetylacetone and nickel acetylacetonate solution in acetonitrile, electrodeposited and thermochemically synthesized Pd nanoparticles (PdNP) and Ag nanoparticles (AgNP) were considered.
As a result of the studies, dependences of the increase of the catalyst oxidation current on the glucose concentration for both types of modifiers were obtained. It has been established that sequential electrode modification with the suspension of surfactants and MWCNT, polydopamine, a solution of ruthenium (III) chloride in acetylacetone and a solution of acetylacetone-nickel (II) complex in acetonitrile has better electrocatalytic properties towards glucose oxidation than other modifications. The sensitivity (dependence of the increase of the oxidation current peak on the glucose concentration) of such a modified electrode was 388.5 ± 13.1 μA/mM. The sensitivity of the electrode sequentially modified with suspension of surfactants and MWCNT, electrodeposited Pd nanoparticles and thermochemically synthesized Ag nanoparticles was 201.6±4.6 μA/mM.
The work was done with the financial support of the Russian Science Foundation (project No. 18-73-00224).
A new single used sensor system modified with clay-protein based composite nanoparticles (Mt-HSA NCs) was fabricated to be used in electrochemical cytosensing application. Mt-HSA NCs was synthesized with desolvation method and was structurally identified by different characterization methods such as attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR), dynamic light scattering (DLS), contact angle, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and ultraviolet–visible (UV-vis) spectroscopy. Pencil graphite electrode (PGE), was used as a working electrode, surface was modified Mt-HSA NCs with physical adsorption method. The electrochemical and contact angle studies showed that the Mt-HSA NCs/PGE had a biocompatible, hydrophilic and large surface area where cancer cells can easily attach to the surface. Besides, the biocompatibility of the PGE surfaces bare and modified with Mt-HSA NCs were carried out by XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay on MCF-7 and L929 cell lines. No cytotoxic effect was seen with both materials (bare and Mt-HSA NCs modified PGEs). Electrochemical impedance spectroscopy (EIS), which has become very popular in recent years, was chosen as a diagnostic method. Under optimum experimental conditions, the linear range was found as from 1.5 × 102 to 7.5 × 106 breast cancer (MCF-7) cells and the limit of detection was found to be 148 cells mL-1. Thus, a simple, effortless and cost effective electrochemical sensor platform for the diagnosis of MCF-7 was developed and applied successfully.
The design of the biological sensor is currently one of the most important fields of analytical chemistry and DNA-based bio (nano) sensors and to examine their compound-DNA interaction related applications continue to show great interest in last two decades (I.C. Lopes et al., 2012). Changes in DNA structure may have serious effects on human health, even for treatment purposes. Especially electroanalytical technique has an important role to determine these effects. In this study, an anticancer drug used in the treatment of cancer since the early 1970s was investigated to determine possible DNA damage during treatment. Drug-DNA interaction analysis has been investigated for the first time under optimized conditions with the drug, which gave an oxidation peaks near the guanine oxidation area using disposable pen graphite electrode (PGEs) and screen printed electrode (SPEs).
In this work, the metal nanoclusters are usually synthesized through a single ligand that limited the properties and applications by the nature of selected ligand. In this work, we developed a new strategy to synthesis gold nanocluster with bi-ligand. The bi-ligand Au NCs were synthesized through a simple one-pot method from mixing Au3+ ions, glutathione (GSH) and 6-aza-2-thiothymine (ATT). The nature and optical properties of bi-ligand gold nanocluster (Au NC) were studied. The green emission bi-ligand Au NC was sensitivity with the change of pH condition. The fluorescence intensity of bi-ligand Au NC would increase in high pH value. Finally the bi-ligand Au NC was applied in the detection of urea by the assistant of urease with a range from 0.1 to 1 mM and detection limit as 0.037 mM. The urea detecting system was also applied in human urine sample with a recoveries were between 95.2 to 104.2 % and the relative standard deviations (RSD) were below 1.59%. This strategy was easily applicable to other ligands, opening a new pathway for the synthesis of metal nanocluster.
In this study, the electrochemical anodic behavior of phenyramidol HCl (PhA) was investigated in aqueous medium. Amine functionalized multi walled carbon nanotube (NH2fMWCNT) modified glassy carbon electrode (GCE) was used as a sensitive and fast sensor for the assay of PhA. Cyclic voltammetry (CV) differential pulse voltammetry (DPV) and adsorptive stripping differential pulse voltammetry (AdSDPV) methods were employed to compare the redox responses of PhA on the surface of bare and modified electrode with NH2fMWCNTs. The results showed a considerable enhancement in the peak current of PhA with AdSDPV. Linear calibration curve was obtained in the concentration ranges of 0.8–100 μM, with a detection limit of 6.13×10-8 M and 2.78×10-8 M from peaks 1 and 2, respectively. The proposed procedure was easily and sensitively applied for the determination of PhA in human serum samples and tablet dosage form with satisfactory recovery value (recovery > 99 %).
Novel biosensors made of polymers offer several advantages over conventional technology such as easy sample preparation procedure and inexpensive characterizations. With the simple electrochemical synthesis of the two different thiazolothiazole containing multichromic polymer in our study, the novel surface was created for glucose sensing. Two different monomers namely 2,5-di(thiophen-2-yl)thiazolo[5,4-d]thiazole (TTzTh) and 2,5-bis(3-methylthiophen-2-yl)thiazolo[5,4-d]thiazole (TTzMTh) were synthesized and their electrochemical and optoelectronic properties were investigated in detail. Since polymer of TTzTh (PTTzTh) architecture showed the best sensing properties compared to the surface modified with poly(TTzMTh) (PTTzMTh), herein we report on the development of a sensitive electrochemical sensor based on a novel architecture composed of TTzTh based multichromic polymer functionalized with glucose oxidase enzyme. The PTTzTh/GOx modified electrode showed a very low limit of detection of 0.075 mM, a wide linear range (0.05-2.0 mM) and low KMapp value (0.97 mM) which are good indicators of the suitable sensor design. In addition, the biosensor was shown to be selective for glucose detection in the presence of several common interfering compounds. The developed platform was employed for real sample analysis, showing good accuracy towards glucose determination in beverage samples, and therefore, the biosensor was suggested as a potential tool for the determination of glucose in beverages.
The accumulation of chemical substances with a planar ring structure between the hydrogen bonds in the DNA helix is called intercalation. In general, these materials use for the detection of DNA hybridization because of their indicator properties. In other words, these chemicals interact in different ways with single (ss) or double strand (ds) DNA, so they show an indicator characteristics.In biosensor design studies, indicators that are electrochemically active use to provide the enhancement of sensor output signal (Aydinlik, Ozkan-Ariksoysal, Kara, Sayiner, & Ozsoz, 2011). One of the electrochemical hybridization indicator is Meldola’s blue (MDB) that is a cationic charged molecule has a planar aromatic ring. Some studies have shown that this substance is a DNA intercalator (Reid et al., 2002). On the other hand, nanomaterial-based detection strategies in biosensor area provide a relatively sensitive, low cost, rapid and easy DNA analysis. In this study, the intercalator ‘‘Meldola’s blue’’ was used in a nanomaterial modified pencil graphite electrode(PGE) and was applied to detect DNA hybridization in connection with differential puls voltammetry. The increased surface area was obtained by nanomaterial modification. In this way, the hybrid signal obtained from the MDB showed a ten-fold increase compared to the bare electrode. Thus, hybridization analysis was performed as highly sensitive with the help of nanomaterial modification. Several factors affecting the DNA hybridization analysis such as probe immobilization, hybridization and indicator accumulation times, etc. were also studied.
2-((2,4-dichlorophenylimino)methyl)-5-(diethylamino)phenol (DMDP) is a novel synthesized Schiff base whose electrochemical properties and DNA interaction were investigated in this study. Differential pulse voltammetry (DPV) was applied to determine the influence of pH of the buffer medium on the anodic peak potential and peak current of 100 µM DMDP in wide pH range (2-10) at glassy carbon electrode (GCE). The DP voltammograms showed one anodic peak (P1a) in the first scan. In the second scan of DPV another peak (P2a) at lower oxidation potential was appeared. From the plot of Ep vs pH, pKa value was obtained as 4.82. Cyclic voltammetry (CV) of 0.1 mM DMDP was performed within the potential range of 0 V to 1.2 V at GCE in order to get useful information about the redox mechanism of Schiff bases. The cyclic voltammogram showed one clear oxidation peak (P1a) in pH 3 buffer solution at about 0.980 V followed by a reduction peak at about 0.390 V in the first scan. While, in the second scan one more oxidation peak (P2a) was appeared at about 0.430 V. The influence of scan rate on the peak current of DMDP was also determined by CV on GCE. The cyclic voltammograms of 0.1 mM DMDP were recorded at multiple scan rates between 5-500 mV s⁻¹. The peak current was plotted against square root of scan rate and scan rate independently for both peaks. The greater correlation coefficient values (0.9979 and 0.9985 for P1a and P2a, respectively) of I vs v½ than (0.9836 and 0.9891 for P1a and P2a, respectively) I vs v indicated the oxidation process of DMDP to be diffusion controlled. The slope values of logI vs logv were observed to be 0.5073 and 0.6837 (∼0.5 theoretical value for diffusion-controlled process) for both peaks, respectively. Hence, the diffusion-controlled process of DMDP was confirmed.
DPV was also used to investigate the DNA-DMDP interaction. The decay in peak current of DMDP by the addition of varying concentration of DNA was used to quantify the binding constant of the DMDP-DNA adduct. The binding constant was calculated to be 5.73 × 10³. DNA biosensor was developed for sensing the DMDP. dsDNA modified GCE was prepared and DP measurements showed the signals of guanine (~1 V) and adenine (~1.2 V) in pH 4.7 acetate buffer solution. After the immersion of dsDNA modified GCE in 40 µM DMDP solution for 3 minutes, the current intensity of the electrochemical signals of dsDNA were observed to decrease. The effect of interaction time on the binding of the Schiff base to dsDNA was performed by DPV. The electrochemical signals of guanine and adenine were observed to be decreased on increasing the interaction time. The largest decrease in adenine and guanine oxidation signals was observed at 600 s. This decrease could be explained as a possible damage in the oxidizable groups of the electroactive bases of DNA. polyG and polyA modified GCEs were also prepared and the results were in line with dsDNA modified GCE.
Nanotechnology development has had a wide impact in a variety of applications, from electronics, energy storage to drug-delivery and tissue engineering. Recently, it became relevant in the construction of biosensing devices. This entails the nano-engineering of electrode surface by nanoscale materials such as nanofibers (NFs). Electrospinning is an efficient and versatile technique for producing complex NF assemblies from a variety of materials, which are suitable platforms for biosensing due to the biocompatibility, customizable morphology and large surface area.
One of the main tasks associated with the development of NF-based biosensors is retaining the functionality of the biomolecule. A suitable approach to this issue is the immobilization of enzymes within clay matrices. This often helps by maintaining the native conformation of the enzyme and promotes adequate orientation, whilst stabilizing it against external factors. Clay minerals have 2D-layered structures and exchangeable cations in the interlayer space, which makes them amenable to modification by a variety or molecules. Although clay-based biosensors have been widely reported, the design of clay-NFs composites as biosensing interfaces is in early stages of research.
Herein, electrospun NFs based on polyacrylonitrile (PAN) and smectite clay, Montmorillonite (Mmt) were employed as base for the development of first generation amperometric glucose biosensors. Due to its cation exchange ability, the clay was intercalated with various organic molecules, prior to electrospinning and showed improved detection efficiency. The linear range of the developed biosensors was up to 2.45 mM with sensitivity up to 55.75 µA/mMcm-1 and detection limits in the range of 3.6 – 2.2 µM.
In the last few decades, foodborne pathogens are increasing concern related to human illnesses and death. It becomes a challenge to detect and identify harmful microorganisms in rapid response and effective ways. The conventional techniques are a laborious, time-consuming, and expensive process. The demand for advanced detection techniques is urgently needed to determine foodborne pathogens. The electrochemical biosensor is more advantages of high simplicity, sensitivity, selectivity, low cost, the rapid detection time for determination of foodborne pathogens . The biotic antibody was modified at the surface of the citrate-capped gold nanoparticles for the capturing of targets. The structure of metal-organic frameworks supported by Fe3O4 nanoparticles was confirmed by uv-visible spectroscopy, transmission electron microscopy, and Ramon spectroscopy. The screen-printed carbon electrode (SPCE) was used, it is a disposable characteristic, and it can also be reused. The metal-organic frameworks (MOF) as supported with gold nanoparticles (AuNPs) for the detection of Escherichia coli K12 (E. coli K12). Previous studies revealed that the active AuNPs deposited with MOF catalyst in solution is challenging research for the target . The results of this study highlight that the developed electrochemical biosensor is a sensitive and reliable source for the detection of Escherichia coli with the linear detection range of 101 to 107 CFU/mL, and the lower limit of the detection was 101 CFU/mL. The proposed method is a more sensitive method for the detection of bacteria than most of the previously reported methods while showing some advanced features like simplicity, stability for a long term, and extended linear range of detection. Cyclic voltammetry (CV) noted that the presence of AuNPs plays an important role to enhance the analyte signal for the detection of E. coli K12. The electrochemical behavior and characterization of the MOF-AuNPs composite revealed the higher electroactive surface area. The developed electrochemical biosensor is very sensitivity, stability, and probably to have a good impact on the applications of foodborne diseases.
Oxidative stress occurs as a result of the imbalance of antioxidants and prooxidants in the presence of copper and iron ions which are major redox-active metals present in serum and tissue, causes the formation of various diseases. The reduced forms of the metal ions induce “site-specific” oxidative damage to the biological macromolecules such as carbohydrate, protein, lipid, and nucleic acid . In this work, protein-protected gold nanoclusters (AuNCs) were used in the determination of prooxidant activity of food, herb, and synthetic serum samples which contain various natural antioxidant compounds. The protein-protected AuNCs were formed using chicken egg white proteins (CEWs) containing thiol groups and gold(III) solution (HAuCl4) . Antioxidant compounds reduced Cu(II) ions to Cu(I) and the formed Cu(I) bound to the S-terminal residues of the CEW-AuNC structure. The protein bound Cu(I) was extracted to the solution medium via ethanolic neocuproine (Nc) as Cu(I)-Nc chelate which was colorimetrically determined at 450 nm. Green tea (Camellia sinensis), red wine, dried blueberry (Vaccinium myrtillus), apple juice, and synthetic serum were studied as real samples. Red wine, apple juice, and synthetic serum samples were prepared by diluting with distilled water in a different ratio. Dried blueberry and green tea were extracted with 80% aqueous methanol (v/v) using the microwave-assisted extraction technique. The total prooxidant activities were calculated as mM epicatechin (ECAT) equivalent. The order of the total prooxidant activities was as follows: green tea >> red wine > dried blueberry > apple juice > synthetic serum. The proposed biosensor is easily applicable, low-cost, convenient, fast, sensitive, and highly reproducible method that can determine the prooxidant activities of natural antioxidants.
The authors thank Istanbul University-Cerrahpasa Application & Research Center for the Measurement of Food Antioxidants (IU-C GAAM) for sharing its research infrastructures. Authors also acknowledge Istanbul University Research Fund, Bilimsel Arastirma Projeleri (BAP) Yurutucu Sekreterligi, for the support given to their Project NAP-2018-28955.
 Iwasaki, Y., Hirasawa, T., Maruyama, Y., Ishii, Y., Ito, R., Saito, K., Umemura, T., Nishikawa, A., Nakazawa, H. (2011) Effect of Interaction between Phenolic Compounds and Copper Ion on Antioxidant and Pro-Oxidant Activities. Toxicol. Vitr. 25(7), 1320-1327.
 Akyüz, E., Şen, F.B., Bener, M., Sözgen Başkan, K., Tütem, E., Apak, R. (2019) Protein-Protected Gold Nanocluster-Based Biosensor for Determining the Prooxidant Activity of Natural Antioxidant Compounds, ACS Omega, 4(1), 2455-2462.
Alzheimer’s disease (AD) is initiated by the progressive accumulation of amyloid-β (Aβ) peptide in the brain as toxic structures such as Aβ oligomers and plaques. Observations in humans show that plaques are found in regions of the brain that display high levels of neuronal activity, sometimes referred to as the default mode network (Buckner et al., 2009). Direct modulation of synaptic activity dynamically regulates brain Aβ levels in awake animals; increased synaptic activity increases brain interstitial fluid (ISF) Aβ levels and vice versa for suppressed activity. These findings strongly suggest a close temporal relationship between synaptic activity and Aβ generation. We have previously used an in vivo microdialysis technique to demonstrate that synaptic activity is temporally linked to ISF Aβ levels. That methodology has limitations of only measuring Aβ every 30-60 minutes; however, Aβ generation likely occurs on the order of seconds to minutes. We have recently adapted an electrochemical technique to study Aβ in vivo on a much faster time scale. The principle behind this approach is that Aβ contains an electroactive tyrosine amino acid at position 10. A voltage applied to the electrode induces oxidation of the tyrosine residue, which releases electrons that the carbon fiber detects as electrical current. We have covalently attached anti-Aβ antibodies to the electrode surface to provide specificity for Aβ detection to the exclusion of the other proteins and molecules present within the brain extracellular space. In our published studies (Prabhulkar et al., 2012) we show that MIEs containing anti-Aβ antibodies can specifically detect either Aβ40 or Aβ42. In vivo MIE studies show that we can detect Aβ every 60 seconds for up to 3 hours in the brain of anesthetized or awake mice. Specificity studies in mice lacking human Aβ demonstrate that the MIEs are 8,000-fold more selective for human Aβ than any other tyrosine in the brain. This enables us to assess fast-acting mechanisms that directly regulate ISF Aβ.
Using MIEs in vivo, we are able to detect a rapid increase in ISF Aβ following a rise in synaptic activity. Large increases in synaptic activity raise Aβ levels within minutes in the APP/PS1 mouse brain, highlighting the close temporal relationship between synaptic activity and Aβ generation in the brain. Micro-immunoelectrodes provide a novel way to explore mechanisms of this relationship with very fine temporal resolution.
Hydrogen peroxide (H₂O₂) is an important reactive oxygen species (ROS) that can be used as mediator in food and environmental processing, pharmaceutical and chemical industry etc. Therefore, its detection with a sensitive method is crucial. Nanomaterial based
electrochemical nanosensors are well suited for the detection of H₂O₂ due to their fast and reliable responses [1,2]. In this work, CoFe₂O₄ @CdSe/Rifampicin modified glassy carbon electrode was used for the sensitive detection of H₂O₂. Firstly, 10 µL of CoFe₂O₄@CdSe magnetic nanocomposite suspension were dropped on electrode surface and dried in oven at 50 °C. After that, the surface of electrode was activated by applying 1.7 V vs. Ag/AgCl (3M NaCl) for 600 s and then Rifampicin nanoparticles were electrodeposited at -0.7 V for 400 s in pH 2 phosphate buffer containing 190 µM of Rifampicin. pH studies were performed and the best pH for H₂O₂ detection was obtained at pH 7. Construction of the calibration plot for H₂O₂ was performed by using amperometric method (−0.4 V vs Ag/AgCl) at the modified electrode and showed linear ranges between 7.0 × 10⁻⁶ M – 0.145× 10⁻³ M with a sensitivity of 143 μA/mM and the detection limit of 0.38 μM (S/N = 3) was calculated from the linear range.
 Asadpour-Zeynali, K., & Mollarasouli, F. (2017). Novel electrochemical biosensor based on PVP capped CoFe₂O₄@CdSe core shell nanoparticles modified electrode for ultra-trace level determination of rifampicin by square wave adsorptive stripping voltammetry. Biosensors and Bioelectronics, 92, 509-516.
 Mollarasouli, F., Asadpour-Zeynali, K., Campuzano, S., Yáñez-Sedeño, P., & Pingarrón, J. M. (2017). Non-enzymatic hydrogen peroxide sensor based on graphene quantum dots- chitosan/methylene blue hybrid nanostructures. Electrochimica Acta, 246, 303-314.
Specific molecular recognition is a key feature of biological processes. In order to substitute biomacromolecules by “biomimetic recognition elements”, fully synthetic receptors so-called molecularly imprinted polymers (MIPs) have been developed.
Molecular imprinting is a method, pioneered by Wulff and Mosbach to create so-called plastic antibodies or plastibodies by the polymerization of functional monomers with or without cross-linkers in the presence of target analyte (template). Subsequent removal of the template leads to the formation of binding cavities which mimics size, shape and functionality of the template. Although MIPs for low molecular-weight substances have been successfully prepared, it is still challenging for biomacromolecules like proteins. This is reflected by the annual number of publications for protein-MIPs, which is only 10 % including enzymes.
Here we present MIP-based sensors for the copper enzymes tyrosinase from mushroom and laccase from Trametes versicolor. Tyrosinase from mushroom has a high homology to the human enzyme, which is a biomarker for skin cancer. The sensor is based on the electropolymerization of the functional monomers scopoletin or o-phenylenediamine in the presence of tyrosinase. The measuring signal was generated either by measuring the formation of a product by the target enzyme or by evaluating the permeability of the redox marker ferricyanide. The MIP-sensor has a linear measuring range up to 50 nM of tyrosinase with a limit of detection of 3.97 nM (R²= 0.994). The ratio of the signal for the MIP and the control polymer without tyrosinase (NIP) was as high as 70. The MIP shows good discrimination towards other proteins, e.g.the signal for tyrosinase was 3.5 times higher than for bovine serum albumin and 2.5 times higher than for cytochrome c.
In the second example laccase-MIP was successfully prepared by electropolymerizing scopoletin in the presence of alkaline-inactivated enzyme as the molecular target. Rebinding of both inactivated and active laccase decreased the ferricyanide peak currents to almost equal extent, thus the MIP does not discriminate the inactivated laccase from the native protein. The relative decrease of signal suppression approached saturation above 10 nM. Furthermore, the surface activity of rebound laccase towards the oxidation of catechol approached saturation above 10 nM, a value close to the value of the measurements with ferricyanide. Interaction of NIP with laccase brought about a 6 times smaller signal of catechol oxidation, thus an Imprinting Factor of 6 was obtained.
Intraoral drug administration comes along with pharmacokinetic advantages, high acceptability by patients and contributes to safe local treatment of oral diseases. Ex-vivo permeation studies are a widely used tool in pharmaceutical research. They are mainly used in galenic drug development and preclinical research providing predictive information on liberation, absorption and permeation behaviour to support intraoral drug development. Conventional settings of permeation studies include diffusion cells in combination with HPLC or UV/VIS spectroscopy as quantification methods. This results in a clinically non-representative setting of measurement time and duration. Therefore, sensitive analytical methods for quantification of permeated and penetrated drugs adjusted to clinical relevant short-term applications and under consideration of physiologically-adapted conditions are required. The aim of this study was to develop and verify a LC-MS/MS method for the suitable quantification of the model drugs lidocaine hydrochloride [LD-HCl] and
triamcinolone acetonide [TA] in ex vivo permeation experiments.
LD-HCl and TA were chosen as model drugs due to their different physicochemical properties (logP; pKa; solubility) and permeation behaviour (flux; membrane retention; trans- or intracellular) as well as their synergistic therapeutic use. The method was developed for simultaneous determination by HPLC coupled with tandem mass spectrometry and included columns with heterogeneous packing material, mobile phases (A: water / B: acetonitrile) with different additives as well as variations on chromatographic conditions (flow rate, column temperature etc.). Mass spectrometric development incorporated the adaption of substance-dependent voltages and ion source parameters for both analytes. To mimic physiological conditions, 10 mM dipotassium hydrogen phosphate at pH 7.4 was selected as acceptor buffer within the permeation studies and served as sample solvent.
After an extensive column screening, the continuous parallel development was initiated with two columns characterized by different column chemistry and dimensions (Atlantis T3 as universal endcapped RP18 vs. Kinetex Biphenyl as orthogonal selective and polarizing phase). Mobile phase additives and resulting pH values affected each analyte contrariwise with regard to ionization, retention time and peak shape. The addition of an amount of 0.1% formic acid decreased the retention time and peak width for LD-HCl compared to addition of 10 mM ammonia buffer salts (retention time – 10.1%; peak width – 53.6%), while all additives had minor qualitatively influences on TA. Therefore a stepwise gradient elution with 0.1% of formic acid in water (A) and in acetonitrile (B) as mobile phases on an Atlantis T3 column and optimized detection in multiple reaction monitoring mode (MRM) were developed. Linearity was attained and verified by 14 calibration standards for lidocaine hydrochloride and by 12 calibration standards for triamcinolone acetonide ranging from 0.244 ng/mL to 1000.0 ng/mL and from 1.22 ng/ml to 1250.0 ng/ml respectively, applying quadratic regression (r² ≥ 0.995).
It was achievable to develop and verify a simultaneous quantification method of LD-HCl and TA by LC-MS/MS to enable sensitive determination of clinically relevant concentrations under physiologically-adapted conditions. Further, the method will be optimized for the expected concentration ranges and validated regarding international bioanalytical validation guidelines.
Metaproteomic analysis of air particulate matter provides information about the properties of bioaerosols in the atmosphere and their influence on climate and public health [1,2]. In this work, a method for the extraction and analysis of free proteins and proteins within cells or bound to the aerosol collected on quartz filters was developed. In particular, five different protein extraction procedures were tested using 50 mmol L-1 tris-HCl (pH 8.8) with protease inhibitors and added with a) 1% sodium dodecyl sulfate (SDS), ethylenediaminetetraacetic acid (EDTA) and 1,4-dithiothreitol; b) 192 mmol L-1 glycine, 0.1 % SDS; glass beads with c) 1% SDS; d) 1% sodium deoxycholate; e) 0.5 % sodium dodecanoate. The extraction optimization for free proteins was performed spiking the filter with 5 target proteins having a different range of molecular weight at different concentrations. Protocols a-d required a precipitation step to remove SDS and EDTA and resulted not compatible with protein trace analysis. As size exclusion chromatography was previously applied to glass fibre filters , a filter aided sample preparation protocol was tested, but it was not suitable due to the presence of carbon in the extract. Protocols d and e resulted in the highest protein recovery for both 5 standard proteins concentration since they exploited detergents, such as SDC and SD, compatible with in-solution protein digestion and subsequent HPLC-MS/MS analysis. Before to analyze environmental collected samples, to simulate a more realistic condition, protocol d was applied to blank filter samples spiked with the spores from an ubiquitous bacterium, i.e Bacillus Subtilis. This test was carried out in order to have an idea of extraction efficiency of proteins within cells or bound to the aerosol material. The optimized method was finally applied to the analysis and characterization of filters from different work environmental sites collected in the Lazio (Italy), such as composting plant, waste water treatment plant and agricultural holding and influenced by urban and rural boundary layer air masses. Seventeen, 100 and more than 300 proteins were successfully identified in composting plant, wastewater treatment plant, and agricultural holding, respectively. The presented profiles of extractable proteins in atmospheric aerosol particles show that proteins encountered in ambient air particulate matter mainly originate from plants, fungi, and bacteria, which is in line with the major categories of primary biological aerosol particles. This study demonstrated that microorganism diversity of bioaerosols is so high that the development of a high-throughput metaproteomic methodologies is fundamental to deeply characterize protein profile and better assess occupational exposure. Understanding the microbial and fungal characteristics of bioaerosols will help developing effective measures to control emission.
This work was funded by INAIL within the project BRIC ID23
 Frölich-Nowoisky J. et al., Atmospheric Research 182 (2016) 346
 Reinmuth-Selzle K. et al., Environmental Science & Technology 51 (2017) 4119
 Liu F. et al., Analytical and Bioanalytical Chemistry 408 (2016) 6337
Recently, the usage of antibiotics are widely spread all over the world resulting in bacterial resistance to these antibiotics which requires alternative medications or higher doses of antibiotics. Implementation of an easy analytical method that can analyze a wide range of β-lactams in a single run is important to reduce time of therapeutic drug monitoring (TDM) in hospitals and minimize the spreading of bacterial resistance.
A novel environmentally harmless HPTLC method was developed and validated following FDA recommendations for analysis of four β-lactams; Cefaclor, Cefotaxime, Cefepime, and Meropenem, in human plasma. A solvent mixture of ethylacetate: methanol: water: formic acid (60: 30: 15:1, by volume) was the used developing system, detection was carried out at 270 nm, and Valacyclovir was used as an internal standard. Lower limit of quantification (LLOQ) was found to be 0.1 µg/band for all the analyzed drugs. Validation parameters were calculated and found to fulfill the international requirements for bio-analytical method validation. Blood samples from volunteers (four groups) treated with a single dose of 1 g of each antibiotic (except for cefaclor, 0.5g) were collected, methanol was used for precipitation of plasma protein, and the developed method was used for calculation of the concentrations in the separated plasma samples. The developed method, being a green one, time and money saving, can be used for TDM of these drugs in clinical studies as well as for quality control analysis in pharmaceutical companies.The proposed method is the first developed HPTLC method for the simultaneous bio-analysis of the selected β-Lactams.
Cabergoline, an ergot derivative, is used as a first line treatment of hyperprolactinemic disorders and also is used in the treatment for Parkinson's disease. Cabergoline structure containing two groups, malonyl urea and amide is highly susceptible to degradation.
Cabergoline was subjected to different stress conditions in order to study its degradation profile. Degradation was carried out according to ICH guidelines including hydrolysis, oxidation, photo, and thermal degradations. The drug was labile to degradation under all conditions except thermal degradation. Three major degradation products were produced and were isolated. Structure elucidation of the degradation products was performed using IR and MS. Two stability indicating chromatographic methods were developed for quantification of the drug in the presence of its degradation products. The first method was HPTLC, where separation was done on silica gel HPTLC aluminum plates precoated with silica gel 60 F254 using a developing system consisting of butanol: methanol: triethylamine (95: 5: 10, by volume) and densitometric scanning at 280 nm. The second method was HPLC, using C18 column and elusion was performed using a mobile phase of acetonitrile: 0.05% aqueous triethylamine (TEA) (pH adjusted to 6.5 using 1% aqueous H₃PO₄) [70:30,v/v]. The flow rate was adjusted to 1.5 mL/min and UV detection was performed at 225 nm. The drug and its degradation products were separated within five minutes. Validity of the developed methods was assured by applying ICH recommendations. Results obtained by the two developed chromatographic methods were statistically compared with the previously published ones. The developed methods were found to be more advantageous than published ones regarding analysis time, studying different degradation pathways, and identifying the degradation products.
Tyrosine (L-Tyr, 4-hydroxy phenylalanine) is a precursor of melanin (a skin pigment), of substances that play a role in the transmission of the nervous influx (dopamine, noradrenaline) and thyroid hormones. L-Tyrosine is also an essential amino acid and indispensable for human to establish and maintain nutritional balance.
The conventional methods, such as chemiluminescence, spectrometric analysis, high-performance liquid chromatography are sustainable with good results, the instrumentation involved are rather expensive with laborious and time consuming multi-step sample preparation procedures. As a suitable outcome, electrochemical detection of L-Tyrosine is cheaper, less laborious, easier to perform and reliable. A carbon based substrate such as graphite (G) is used as electrode material due to good electrical conductive properties.
We evaluated and tested the sensors based on plain graphite paste and on Chitosan modified graphite paste for the assay of L-Tyrosine in pharmaceutical capsules. We used the properties of Chitosan (Ch) a linear β-1,4-linked polysaccharide (similar to cellulose) extracted from animals such as exoskeletons of crustaceans (mainly crabs and shrimps), insects and cell walls of fungi, as modifier due to its most important features in structural versatility owing to the presence of reactive amino and hydroxyl groups in its linear chain and which are amenable to chemical modification.
Two electrochemical sensors were proposed for the determination of L-Tyrosine in pharmaceutical samples. The electrochemical sensors were based on plain graphite paste and chitosan modified graphite paste. Working conditions, e.g. pH, supporting electrolytes have been optimized. The results revealed for both electrodes very low limits of quantification (LOQ) for plain graphite paste based sensors and for Chitosan modified paste sensors. A higher sensitivity was obtained for the sensor based on plain graphite paste (G). The uniformity content test showed that L-Tyrosine can be recovered in its pharmaceutical formulation with an average value higher than 98.00% and a relative standard deviation (RSD%) value less than 1.00% (N=5).
The Adenosine triphosphate (ATP) molecule is energy chance factor of the cells. The energy is stored between the bond of second and third phosphate groups and that makes ATP fuel of cellular processes. ATP is synthesized by cellular respiration in the presence of oxygen and nutrients. However, ATP is depleted in the case of ischaemia, hypoxia and hypoglycaemia that affect the variety of energy dependent processes that are crucial to maintain cellular life.
To understand cellular mechanisms including ATP depletion, many different techniques can be used ranged from molecular to spectroscopic techniques. Among spectroscopic techniques, Raman spectroscopy is powerful vibrational technique which can be used not only for the characterization of materials but also for getting information from intracellular mechanisms. Raman spectroscopy has a disadvantage that provides weak signals from cellular structures. To overcome this problem, noble metals such as gold (AuNPs) and silver nanoparticles (AgNPs) can be used to provide enhanced Raman signals. This technique is a nonlinear form of Raman spectroscopy and called as surface enhanced Raman scattering (SERS). With the use of SERS, detailed information about cellular mechanisms can be obtained.
In this study, to investigate ATP depletion; sodium azide, 2-Deoxy-D-glucose and low temperature was used. PNT1A (normal prostate epithelium) and DU145 (human prostate cancer) cell lines were treated with the inhibitors for 2 hours and then with the approximately 50 nm AuNPs for 24 hours. To understand the effect of ATP depletion agents, cytoskeleton structure of cells were analyzed using confocal microscopy and the effect of receptor-mediated endocytosis were analyzed by flow cytometry. SERS spectra of single living cells were obtained after treatment of both inhibitors and AuNPs.
Vinorelbine (sold under the brand name Navelbine), one of the semisynthetic derivatives of Vinca alkaloids, has been widely used either alone or in combination with other drugs in the treatment of leukemia, lymphoma, advanced testicular cancer and Kaposi's sarcoma.
From the electrochemical point of view, only one study that was quite old has been reported on its voltammetric characteristics so far (Brett et al.). Keeping the above knowledge in mind, in the present study, a novel application of single-use pencil graphite (PG) electrode is introduced for the determination of Vinorelbine. The electrochemical oxidation of this compound was first investigated by cyclic voltammetry in aqueous solutions. Special attention was given to the use of adsorptive stripping voltammetry at a surface of PG electrode and glassy carbon (GC) one (for comparison purpose) in aqueous solutions over the pH range of 2.0-12.0 both without and with the addition of different charged surfactants. The sensitivity of the stripping voltammetric measurements was significantly improved when the anionic (sodium dodecylsulfate, SDS) and cationic (tetra-n-butylammonium bromide, TBAB) surfactants were present in the Vinorelbine-containing electrolyte solution at pH 2.0-4.0 and pH 9.0-10.0, respectively, by using PG electrode. Using square-wave stripping mode, Vinorelbine yielded a well-defined voltammetric response in Britton-Robinson buffer pH 10.0 containing 3×10⁻³ M TBAB at +0.75 V (vs. Ag/AgCl) (after 120 s accumulation at +0.0 V). The process could be used to determine this compound in the concentration range of 2.3×10⁻⁸ – 5.8×10⁻⁶ M, with a detection limit of 7.5×10⁻⁹ M (base-5.8 ng mL⁻¹). The proposed method was successfully applied to pharmaceutical formulations and the spiked human urine samples.
Brett, A.M.O., Grazina, M.M.M., Macedo, T.R.A., Oliveira, C.& Raimundo, D. (1993). A study of the electrochemical oxidation of Navelbine. Journal of Pharmaceutical and Biomedical Analysis, 11(3), 203-206.
Study of protein-metal ion interactions has always been fascinating for the researchers owing to the important role of metal ions in a number of biological functions. All proteins including metalloproteins are capable of interacting with certain metal ions, and their selectivity is particularly important, as some of the metal ion-protein interactions are physiologically as well as pathophysiologically significant. These interaction studies have led to the identification of a library of promising metal-based complexes with encouraging therapeutic potential. Serum albumin, being the most abundant plasma protein, plays vital role in transporting and distributing drugs including metal ions in the living system. The interaction of metal ions with various biological proteins depends on a variety of factors. Various analytical techniques have been employed for the effective measurement of these interactions, including Affinity Capillary Electrophoresis, X-ray crystallography, Circular Dichroism, Thermal shift assay, etc. Recently, FT-IR spectroscopy has emerged as an effective tool for the measurement of these interactions and it yielded promising results. In this study, the binding interactions of some biologically important metal ions such as Al3+, Li+, Ni+2, Pd+2, Au+ and Cu+ with bovine serum albumin (BSA) were measured using FT-IR spectroscopy. The salts of selected metal ions were allowed to interact with BSA at physiological temperature and pH in vitro and the resulting complexes were analyzed using FT-IR. Spectra were obtained over 100 scans at a transmittance range of 4000-400 cm-1 and a resolution of 4 cm-1. A considerable reduction in the C=O stretching (corresponding to amide I) and C=N stretching (amide II) intensities were observed for the complexes demonstrating significant protein-metal ions interactions. Amide I band was also revealed to be shifted from 1652 cm-1 in case of free BSA to 1656 (Al3+, Li+), 1654 (Ni2+), 1653 (Pd2+), and 1657 (Cu+) cm-1 for complexes. Second derivative resolution enhancement was utilized to study the shape of amide I band of resulting globular proteins which was characteristic of their secondary structures including α-helix (1660-1650 cm-1), β-sheet (1637-1614 cm-1), random coil (1648-1638 cm-1), β-turn (1678-1670 cm-1) and β-antiparallel (1691-1680 cm-1). Self-deconvolution and curve fitting methods were applied to determine the secondary structures of protein and metal-protein complexes. These secondary structures were analyzed and the percentages of α-helix, β-sheet, random coil, β-turn and β-antiparallel were calculated to measure the changes, if any, upon complexation. Interestingly, a remarkable decrease (16.66-41.93%) in the α-helix was seen after complexation with various metal ions studied with significant increase in random coil which was considered to be the measure of interaction. The intensities of binding interactions were found to be decreased in the order Cu+ > Al3+ > Ni2+ > Li+ > Pd2+ > Au+. These results were comparable to the results obtained in a similar study performed in our lab using Affinity Capillary Electrophoresis (ACE). Therefore it can be concluded that, FT-IR technique can be successfully employed to measure the binding affinities of metal ions with biological proteins and various advantages are associated with this technique including ease-of-analysis and cost-effectiveness as most important ones.
The present study describes a novel reversed-phase high performance liquid chromatographic (HPLC) method for quantification of anticancer agent everolimus from mouse plasma and liver samples. Everolimus is a mammalian target of rapamycin inhibitor, used against cancer and organ transplantation. The presented method is suitable for preclinical studies that aim to study pharmacokinetics or toxicokinetics of everolimus in mice. Blood and liver samples taken from untreated mouse. Plasma was separated and liver samples were homogenized using a mechanic homogenizer. 200 µl plasma or liver sample were spiked with internal standard repaglinide. To this mixture the precipitation reagent (saturated zinc sulfate in 10:1 methanol/water) was added. The mixture was vortexed then centrifuged for 10 mins. The supernatant was loaded onto a solid phase extraction cartridges, previously conditioned with methanol and water. Everolimus and repaglinide were eluted with methanol. Chromatographic separation was carried out on C8 reversed-phase column (Luna, Phenomenex, 100×4.6 mm, 5 μm) using an isocratic mobile phase acetonitrile: ammonium acetate buffer (60:40,v/v at pH 4.0) at flow rate of 1 ml/min. The HPLC system consisted of Shimadzu LC 20 with LC-20AT pump and SIL AT-HT autosampler (Shimadzu, Japan). Monitoring was made by UV detection at 278 nm (SPD-20A Shimadzu, Japan). The retention time was nearly 14.3 min for everolimus and 5.6 min for internal standard repaglinide. The method was found precise, accurate and specific, with a linear range from 0.1 to 5 µg/mL in plasma and liver homogenates. The coefficient of variation of intra- and inter-day was less than 5%. Limit of detection was found 2.49 and 7.01 ng/mL and limit of quantification was found 7.55 and 21.26 ng/mL in plasma and liver, respectively. Using this method we also tested plasma levels and liver distribution of everolimus in mice following its oral administration. This simple and reliable HPLC method can be used further pharmacokinetic studies realized as preclinical phase.
In this work the development of two types of modified electrodes, used for the analysis of drugs, is presented. The first type corresponds to glassy carbon electrodes modified with carbon nanotubes and different ionic liquids (IL) and the second one to carbon paste electrodes modified with IL. Both types of electrodes were modified with IL of different types: imidazolium as 1-butyl-3-methyl-imidazolium hexafluorophosphate and 1-butyl-3-methyl-imidazolium tetrafluoroborate, and pyridinium type, such as N-butyl-3-methylpyridinium trifluoromethanesulfonate, N-butyl-3-methyl pyridinium hexafluorophosphate and N-butyl-4-methylpyridinium tetrafluoroborate.
The electrochemical characterization of the different modified electrodes was carried out with the redox mediators potassium ferricyanide, ferrocene ethanol and ruthenium (III) hexamine, using cyclic voltammetry. Each IL was tested in different percentages (5% - 15% w/w), exhibiting a significant increase in the anodic and cathodic currents of each mediator in all the modified electrodes studied, depending on the percentage of IL tested.
Different electrodes modified with IL were selected, both for the study of electrochemical behavior and the development of analytical methods for the quantification of different drugs by differential pulse voltammetry, in Britton Robinson buffer solution. In this way, the electrochemical behavior of the drugs pseudoephedrine, benserazide, levodopa, methyldopa, chlorphenamine, sulfamethazine and sildenafil was studied, developing for each drug methods for quantification using differential pulse voltammetry, determining the corresponding analytical efficiency parameters. As an example, Table 1 summarizes the analytical parameters obtained for sildenafil and sulfamethazine.
This work was funded by Project FONDECYT N ° 1150861.
|Ip = 48.8 × C (mg/mL) + 0.25 (r2 = 0.999)||Ip = 0.0275 × C (μg/mL) + 11.5 (r2 = 0.993)|
|Linear range (μg/mL)||10 – 90||150 - 960|
|Experimental conditions||pH = 3, Eapp.= -0.3 V, tacc. = 60 s||pH = 3.2, tacc. = 5 min|
A new enrichment and determination method for Methyl Paraben (MP), Propyl Paraben (PP) and Butyl Paraben (BP) in the cosmetic samples has been developed based on Fabric Phase Sorptive extraction (FSPE) and HPLC-DAD analysis. In proposed method; MP, PP and BP analytes were drawn to the Sol-Gel Carbowax-20M fabric phase in the presence of pH 5.0 buffer and enriched with methanol prior to chromatographic determinations by desorbing to a lower volume. The samples were transferred to HPLC vials by filtration with a 0.45 μm porous PTFE filter before HPLC analysis. Experimental variables such as pH, adsorption time, desorption solvent and its volume were studied and optimized in detail. By using optimal conditions, analytical parameters such as linear ranges, detection limits, pre-concentration factor for each paraben were calculated by using experimental data.
In the developed method; MP, PP and BP molecules were analyzed on gradient elution of methanol, acetonitrile and 3% acetic acid with DAD detector at 256 nm wavelength. Limit of detection(LOD) values for each paraben were calculated as 2,85, 2,98 and 2,75 ng mL-1, respectively. Relative standard deviations (RSD) were below 3.80 % for determinations of model solutions including 100 ng mL-1 paraben. Finally, the developed method has been applied to cosmetic products such as hair conditioner, hair foam, hand-body cream, blush, lipstick, eye shadow and eye pencil and quantitative results have been obtained in recovery experiments.
"Acknowledge This study has been supported by Sivas Cumhuriyet University Scientific Research Projects Commission as the research projects with the ECZ-056 code."
Two liquid chromatographic(LC) methods have been developed and validated by using RP-HPLC and RP-UPLC for the simultaneous estimation of Montelukast (MON),Levocetirizine Dihydrochloride (LEV) and Desloratadine (DES) in pharmaceutical formulations. For both methods; the mobile phase consisted of acetonitrile with triflouroacetic acid and ammonium acetate buffer solution by flow program at 25°C, wavelength is 238 nm, the chromatographic separation was performed with phenyl columns. Paracetamol used as an internal standard(IS). The developed methods were validated by validation parameters such as linearity, accuracy, precision as per ICH Guidelines. Both methods were compared by performing f test and t test at the 95% confidence level and have been passed f - t tests, thus they were verified statistically.
|Column||Inertsil, Ph 3 100×4.6 mm, 3µm||Zorbax SB-Phenyl, 50×4.6 mm, 1.8µm|
|Flow rate (mL min-1)||1,2||0,6|
|Gradient flow program total run time (min)||15||10|
|Mobile Phase||Mobile Phase Acetonitrile (containing triflouroacetic acid,0,15%): Buffer- 5 mM ammonium acetate( pH adjusted to 3,2 with triflouroacetic acid)||Mobile Phase Acetonitrile (containing triflouroacetic acid,0,15%): Buffer- 5 mM ammonium acetate( pH adjusted to 3,2 with triflouroacetic acid)|
|Injection Volume (μL)||20||10|
Degradation products are unwanted chemicals that can affect pharmaceutical safety because of the potential to cause adverse effects in patients. Consequently, it is crucial to focus to understand the effect of possible degradation products on cellular mechanism, SERS can be used as a powerful technique. At this perspective, the aim was investigation of the effect of drug degradation at thermal and UV conditions on cells with SERS in this study. To achieve the aim, model cancer drugs 6-thioguanine and capecitabine were chosen. Initially non-toxic doses of drugs were chosen by cytotoxicity assay. Then, the drugs were going to be degraded in both thermal conditions at 70 ºC for 3 h and UV conditions at 254 nm for 3 h. After then, healthy and cancerous cells (PNT1A human prostate and DU145 human prostate cancer) are going to be exposed to degraded drugs in aqueous solutions as both time and concentration dependent. Afterwards, SERS measurements of live single cell were done for both control groups and degraded drug exposed groups. Obtained spectra were compared and found that expose to the degradation drug provide spectral changes for living single cells. And it can be concluded as that the effect of the degradation of drugs on cellular mechanisms can be investigated by SERS.
Teucrium L. commonly named ‘Germanders’, is one of the largest genus belonging to Lamiaceae family which has more than 290 species all around the world. The species are widely growing mild parts of Asia, Europe, America, Australia and North Africa. Teucrium is represented by 34 species (with 46 taxa) in Turkey, 16 of which are endemic. The species are one of the edible herbs, they are used to prepare herbal tea, flavoured wines, liqueurs, beers and also as a spice in many countries. Teucrium polium L., also known ‘tüylü kısamahmut otu’ are widely distributed perennial herbaceous flowering plant in Anatolia and its infusion is quite popular in Anatolian folk medicine to treat diabetes, stomach problems, abdominal cramps and dysorexia. In present study, the aerial part of Teucrium polium was extracted with different solvents such as hexane, chloroform, methanol. Infusion of plant was also prepared. All extracts were studied against Staphylococcus aureus, Salmonella typhimurium, Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Pseudomonas aeruginosa, and Candida albicans using microbroth dilution method. The antioxidant activity was determined by CUPRAC and FRAP assay and free radical scavenging activity (by DPPH•). As to the antimicrobial activity, the MIC values ranged from 0.031 μg/mL to 2000 μg/mL for all tested microorganisms. It was concluded that infusion extract contain the highest amounts of total polyphenolics, expressed as gallic acid equivalents (59±1.8mg/g extract). According to three assay, all extracts showed moderate to strong antioxidant activity
Imidazole derivatives are of great importance in the pharmaceutical industry because they present in the structure of many synthetic drug molecules. These structures have many different biological activities such as anthelmintic, antifungal, antiviral, anti-HIV and anti-cancer . Clotrimazole, 1-[(2-chlorophenyl)-diphenylmethyl]-1H-imidazole, is a non-toxic synthetic imidazole with broad-spectrum anti-microbial activity . This azole fungicide acts by inhibiting the activity of cytochrome P450 lanosterol C14α-demethylase (EC 188.8.131.52) in fungal ergosterol biosynthesis .
The use of the proposed model related to the retention of the ionizable solute with the pH and composition of the mobile phase should be very helpful in the optimization of reversed phase liquid chromatography (RPLC) method . In this study, the correlation established between retention factors of solutes and the pH of the mobile phase (acetonitrile–water mixture) was used to optimize the pH of the mobile phase. The optimized mobile phase is composed of acetonitrile and phosphate buffer adjusted to pH 5.5, with 45% (v/v) acetonitrile. The optimum separation condition was achieved with the Kinetex Core-Shell C8 (Phenomenex, 150mm×2.6 µm, 4.6 mm) column at 195 nm detection wavelength. The temperature of the column and flow rate were set at 25°C and 0.8 mL/min, respectively.
This proposed method was validated for the separation and quantification of clotrimazole using dicloxacillin as an internal standard. The calibration curve was linear (r2>0.99) in the concentration range of 2-12 μg/mL for clotrimazole. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.166 and 0.544, respectively. The recovery of the 10 mg clotrimazole containing cream formulation was 96.30%. The method was rapid with a retention time of clotrimazole and internal standard observed at 4.83 and 7.20 min, respectively. The developed method was successfully applied to the determination of clotrimazole in a topical pharmaceutical cream formulation.
Dofetilide is a sulfonamide class III antiarrhythmic agent and potassium channel blocker. Unlike other antiarrhythmic agents, oral dofetilide did not increase mortality in patients with a recent myocardial infarction or congestive heart failure. Only a limited number of studies of this compound are found in the literature. Any advance in the development of analytical methods for its determination or in the knowledge of the physicochemical properties of this drug provides a great contribution. The separation and quantify of this drug is critical for the successful conduct of preclinical, biopharmaceutical and clinical studies.
In this study, the combined effect of mobile phase variables (ACN content, pH of the mobile phase) on the chromatographic behavior of dofetilide was investigated. The chromatographic separation is realized using a Kinetex Core-Shell EVO C18 (250 × 4.6 mm I.D, 5 μm) column using UV detection. Isocratic chromatographic study was performed by setting the temperature at 37oC(biorelevant temperature). The optimized mobile phase consisted of binary mixture of acetonitrile-water containing phosphate buffer (pH 6.8). This proposed method was validated for the separation and quantification of dofetilide using oxacillin as an internal standard.
The calibration curve was linear between the concentration range of 2–120 μg/mL. Intra‐ and inter‐day precision values for dofetilide in human urine were less than 2.0%, and accuracy (relative error) was better than 1.0%. The recovery of dofetilide from human urine were between 99.22 and 100.39%. The limits of detection and quantification of dofetilide were 0.31 and 1.32 μg/mL, respectively.
In Algeria, the stems and leaves of a Mediterranean shrub Rhamnus alaternus L or M'liles were used to treat jaundice and liver disorders caused by malaria, this treatment is known in most Maghreb countries or hepatitis viral hepatovirus type A is endemic, indeed this remedy accelerates healing and whose effectiveness has been proven.
Rhamnus alaternus L is a purgative species indeed the bark of the roots or stems and even the leaves are rich in anthracene derivatives (emodin), but also in polyphenols thus having hepatoprotective properties (antioxidant effect), but according to several studies the alaterne has been incriminated in several cases of hepatotoxicity.
The aim of this work is to establish an association between the consumption of this plant and the appearance of hepatotoxicity by analyzing its chemical composition by the HPLC technique.
Monoamines such as dopamine, noradrenaline, epinephrine, serotonin, and their metabolites are an important group of compounds in the central nervous system (CNS). Their main functions are neurotransmission through neuronal or hormonal signals in various physiological processes, and their imbalance or dysfunction are associated with various disorders . They are mainly synthesized from two amino acids, namely tyrosine and tryptophan; the metabolic pathways of the monoamines are shown in a simplified diagram in Figure 1 .
Reverse phase high performance liquid chromatography with electrochemical detection is used to determine some catecholamines and indolamines in brain samples, in this study. As a result of the method development studies, 10 compounds were separated using a Kinetex® series reversed phase column having F5 functional group. The mobile phase was composed of 20 mM citric acid, 0.07 M KH2PO4, 100 mM EDTA, 5.3 mM 1-octanesulfonic acid, 3.1 mM triethylamine, 8 mM KCl and 11% (v/v) methanol. The flow rate was 0.35 mL/min, and the injection volume was 1 µL. The signals were detected using a VT-03 flow cell; the three electrodes configuration of the cell was as follows: Glassy carbon working electrode (with a 3.00 mm diameter and an internal volume of 0.18 μL with a 25 μm inter-hole seal), platinum auxiliary electrode and an in-situ Ag/AgCl (ISAAC) reference electrode. The oxidation potential was +800 mV, and signal were monitored within 2 nA range with a filter of 0.005 Hz.
In this study, a new chromatographic method was developed and applied for the determination of monoamines in brain tissues using an F5 bonded core-shell silica column. Various parameters (reproducibility, linearity, accuracy, detection limit and stability of samples) of the method were investigated. As a result, noradrenaline and its metabolites (vanillylmandelic acid and 3-methoxy-4-hydroxy phenylglycol), dopamine and its metabolites (3,4-dihydroxyphenyl acetic acid and 3-methoxy tyramine) were analyzed in brain tissues by separating with serotonin, 5-hydroxyindole-3-acetic acid and adrenaline.
In January 2012, ivacaftor (IVA) (Kalydeco®, Vertex Pharmaceuticals), a small-molecule potentiator of the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, was approved by the US Food and Drug Administration for the treatment of patients with cystic fibrosis who have a G551D mutation in the CFTR gene . The investigational CFTR potentiator IVA (VX-770) increased CFTR channel activity and improved lung function in subjects with CF who have the G551D CFTR gating mutation . In the current work, a new analytical method was developed for quantitative determination of IVA in the presence of its degradation products. The quantitative determination of IVA was carried out by using LC-DAD. The separation of IVA and its degradation products was carried out using a core-shell particle column (Kinetex C18, 150 × 2.6 mm from Phenomenex). The mobile phase, which was pumped at the rate of 0.25 mL/min, was consisted of 0.1% (v/v) formic acid in water and 0.1% (v/v) formic acid in acetonitrile (63:37 (v/v), pH=2.6).
In the presented work, while performing the separation of IVA in the presence of degradation products, its chromatographic–behavior on two different columns was also examined. An exemplary chromatogram recorded under optimum conditions was given in Figure 1, in which IVA signal was observed at 8.3 min besides the degradation products produced under oxidative stress conditions.
Analytical method validation as per ICH Q2(R1) was realized to display real-time performance of the method. This is the first study in the literature to determine the quantitative analysis of IVA in the presence of degradation products and also showed its the degradation products with using DAD.
1. Davis, P.B., U. Yasothan, and P. Kirkpatrick, Ivacaftor. 2012, Nature Publishing Group.
2. Yu, H., et al., Ivacaftor potentiation of multiple CFTR channels with gating mutations. Journal of Cystic Fibrosis, 2012. 11(3): p. 237-245.
Nowadays prostate cancer is the second most common cancer death after lung cancer among men. Prostate cancer; it is an uncontrolled false cell proliferation as a result of mutations or genetic code differentiation in prostate cells. Therapeutic management of prostate cancer has been developed in three areas: symptomatic therapy, chemotherapy and hormone therapy.
Within the scope of this research project, drug selection was made based on the hormonal treatment method used to stop the progression of cancer in the treatment of prostate cancer. These drugs interact with receptors for luteinizing hormone (LH) in gonads and prevent hormonal effect from the pituitary gland. Within the scope of the project, Zoladex® pharmaceutical preparation containing the active ingredient of goserelin as goserelin acetate was selected as the hormonal treatment.
This research project consists of examining the analytical methods applied to the analysis of goserelin acetate and spectroscopic analysis of the goserelin acetate active substance. Mehrnoosh S. and his friends  performed chromatographic and LC-MS / MS methods for goserelin containing peptide structure. Cafer S. and his friends[2,3] used dosage forms, drugs and electroanalytical and chromatographic analysis for the determination of samples for the treatment of prostate cancer in his work. Researchers have approved the analytical methods they have developed under optimal conditions and report their usability in routine drug analysis and industry. Also in the literature studies, goserelin in USP XXXVI  chromatographic method has been proposed for the analysis of acetate. As we did not observe the spectrophotometric analysis of the drug in the literature studies, we performed the analysis of the goserelin acetate active substance by UV-VIS and derivative spectroscopy methods. In the analysis, the concentration range 3,8-47,5 µg / ml; the regression coefficient 0.9989; detection limit of 1.22µg / ml; and the quantitation limit were found to be 3.71 µg / ml. The results obtained in the analyzed literature and the analyzes were found to be a good fit compared to the pharmacopoeial methods. No interference was observed between the usual pharmaceutical excipients and the drug actives in the methods used.
 S Shirangi, M., Hennink, W. E., Somsen, G. W., Nostrum, C. F., (2016), Acylation of arginine in goserelin-loaded PLGA microspheres, European Journal of Pharmaceutics and Biopharmaceutics, 99, 18–23
 Saka, C., (2019), Electroanalytical Approaches for Determination of Prostate Cancer Drugs in Biological Samples and Dosage Forms, Critical Reviews in Analytical Chemistry, DOI: 10.1080/10408347.2018.1538768
 Saka, C., (2019), Chromatographic Methods for Determination of Drugs Used in Prostate Cancer in Biological and Pharmacological Samples, Crıtıcal Revıews In Analytıcal Chemıstry, vol 49, No. 1, 78-99
 USPXXXVI, Official Monographs, 3762-3763
Headache is one of the most common symptoms worldwide. Migrane headache has an important place among the primary headache syndromes. Migrane is a neurological disorder characterized by severe recurrent headache, nausea, vomiting, photophobia and phonophobia.
Sumatriptan is a sulfonamide that consists of N,N-dimethyltryptamine bearing an additional (N-methylsulfamoyl)methyl substituent at position 5. Selective agonist for a vascular 5-HT1 receptor sub type (probably a member of the 5-HT1D family). Used (in the form of its succinate salt) for the acute treatment of migraine with or without aura in adults.
In this research, quantitative determination of sumatriptan which affect antimigraine was achieved by spectrophotometric methods. UV absorption spectrums of various concentrations of sumatriptan prepared in acetonitrile was obtained. UV spectrums taken was between 220-350 nm. When these curves were evaluated sumatriptan can be detected with 6-120 µg/ml concentration range of sensitivity by the zero order and derivative spectrophotometry. Calibration graph was obtained at the wavelength 282,5 nm in direct absorbance measurement method by measurement of the original absorbance values. Calibration graph was obtained by measurement of the absorbance at 296,1 nm wavelength value taking the derivative of the original spectrum from the first stream. Correlation coefficient was found as 0,9995 for UV absorption spectrophotometry and 0,9991 for derivative spectrophotometry, respectively. Limit of detection was found as 1,36 µg/ml and 1,72 µg/ml and limit of quantitation was found as 4,13 µg/ml and 5,2 µg/ml for zero-order and derivative spectrophotometry, respectively.
Also the methods that developed for the quantitative determination was applied tablet pharmaceutical formulation which are used in Turkey and when the results was compared with those of various pharmacopeias and literature , it was found that the amounts of this drug was between the given limits.
The purposed methods have been validated. In order to demonstrate the validity and applicability of the proposed spectrophotometric method recovery tests were carried out. High percentage recovery shows that the method is free from the interferences of the commonly used excipients and additives in formulations of drug.
This proposed method is suitable for quality control laboratories where economy is essential.
 European Pharmacopoeia, 2005. European Department for the Quality of Medicines, fifth ed., vol. II. Council of Europe, Stranbourg, France. pp. 2522.
 Kudige Nagaraj Prashanth, Kanakapura Basavaiah, Cijo Madatil Xavier, Development and validation of UV-spectrophotometric methods for the determination of sumatriptan succinate in bulk and pharmaceutical dosage form and its degradation behavior under varied stress conditions, Journal of the Association of Arab Universities for Basic and Applied Sciences, 15 (1), 43-52, 2014.
The species of the genus Centaurea are known to have many biological activities. Bioactive sesquiterpene lactones from Centaurea species showed a several antifungal properties and an important cytotoxic activity against human cell lines in vitro. The present work aims to evaluate the antiproliferative effect of a new γ-lactone named maroccanin together with 4 sesquiterpene lactones isolated from the chloroform soluble part of the aqueous-MeOH extract of the leaves and flowers of Centaurea maroccana Ball. The Sulforhodamine B (SRB) assay was used to measure cellular proliferation as well as to detect decreased cell mass derived from the toxicity of the compounds isolated. Human PC-3 cell line and foreskin BJ fibroblasts were treated at different concentrations of Centaurea plants compounds during 24h. Vital Epifluorescence microscopy was used then to detect the effect of Centaurea compounds in nuclear chromatin condensation and alterations in mitochondrial polarization in all cell lines used. The western blot was used to determine the effect of the compounds on the content of prostate cancer cells in p53 protein. Between the 5 compounds tested, 3 sesquiterpene lactones showed a high anticancer cytotoxicity effect again PC-3 cells when the effect was not significant in BJ cells. IC50 of 11,13-dehydromelitensin, 8a-[2’-hydroxymethyl-2’-butenoyloxy]-dehydromelitensin and 2’-dihydroxyethyl-acryloxy)-elema-1(2),3(4),11(13)-trien-6,12-olide were 2,55, 8,39 and 4,71 µg/ml respectively. These compounds induced also alterations in mitochondrial polarization and in nuclear morphology of cancer cells which are characteristic of apoptosis. The results obtained in the present study showed that sesquiterpene lactones of Centaurea maroccana may be promising anticancer agent.
Many scientific and healthcare studies worldwide indicate that there was an increase in the prevalence of attention deficit (ADD) or attention deficit hyperactivity disorder (ADHD) among children.
Behavioral therapy and medicines are used in ADHD treatment. Atomoxetine is noradrenaline-specific reuptake inhibitor used clinically for the treatment of childhood and adult attention deficit hyperactivity disorder (ADHD) as part of a comprehensive treatment program.
The BCS (Biopharmaceutics Classification System)-based biowaiver approach is meant to reduce in vivo bioequivalence studies. In vivo bioequivalence studies may be exempted if an assumption of equivalence in in vivo performance can be justified by satisfactory in vitro data. Solubility study and in vitro dissolution profile in three different dissolution media (0.1 M HCl pH 1.2, acetate buffer pH 4.5 and phosphate buffer pH 6.8) were performed.
The drug release was tested by HPLC method. The method was validated to meet requirements as per ICH guidelines which include specificity, precision, linearity, intermediate precision, accuracy, stability and robustness.
With regards to solubility and permeability Atomoxetine hydrochloride is highly soluble and highly permeable and is classified as a BCS class I drug substance. The corresponding dissolution profiles showed more than 85% drug release within 15 min without significant differences between generic and reference product.
In vitro dissolution profile results obtained for generic and reference drug product can be used instead of in vivo bioequivalence studies.
Electrochemical anodic behavior of Benzimidazole difumarate was investigated in aqueous medium. Cyclic voltammetry (CV) differential pulse voltammetry (DPV) and adsorptive stripping differential pulse voltammetry (AdSDPV) techniques were applied to investigate oxidation behavior of emedastine in aqueous solutions. For experimental conditions; selecting pH, supporting electrolyte, scan rate were examined.
Bean husk is one of the waste products generated during bean processing, which are often improperly disposed on farmlands. In order not to be a nuisance and consequently lead to environmental pollution, an environmentally friendly approach of managing this waste material is essential. Composting was chosen as the approach because of the biodegradable nature of the waste material. Thus, in this study bean husk was composted and the changes that took place in the material during the composting process were evaluated. The study was carried out for ten (10) weeks, and the changes in the pH, temperature (℃), moisture content (%), electrical conductivity (μS/cm), total carbon to nitrogen ratio, and the loss in weight were monitored. Fourier transform infrared spectroscopy (FTIR) was also used to study the changes in the waste material during the composting process. The results showed that the pH ranged from 7.03 - 9.40, while the temperature, moisture content, electrical conductivity, carbon to nitrogen (C:N) ratio ranged from 26.33 - 29.70 ℃, 25.18 - 31.39 %, 146.70 - 247.86 μS/cm, 35.25 - 74.18 respectively. The loss in weight was from 32.91 - 60.00 %. The FTIR analysis showed the presence of C-O, aromatic C=C, aliphatic C-H stretching vibrations which is attributed to (1033 cm-1, 1200-950cm-1 and 3000-2800 cm-1) respectively, and these correspond to functional groups in lignocellulosic materials like the beans husk. This study shows that the waste bean husk can be composted, as the results obtained are consistent with previous studies.
The first generation of polysaccharide-based chiral stationary phases (CSPs) for liquid-phase separation of enantiomers were prepared by physical coating of polysaccharide derivative onto the surface of silica. On the one hand, this is a quick method that does not require pre-activation of silica. However, the CSPs prepared by this way may suffer from stability problems in some solvents used as mobile phase components in high-performance liquid chromatography (HPLC). This problem can be solved by covalent immobilization of polysaccharide-based chiral selector (CS) on silica. The advantage of this method is that immobilized CSPs are stable, compatible with different type of mobile phase components and capable for reversal of enantiomer elution order at elevated temperatures.
The major research goal of the project is comparison of cellulose tris(3-chloro-5-methylphenylcarbamate) coated or covalently immobilized on silica for separation of enantiomers in acetonitrile, methanol and mixture of n-hexane and isopropanol (v/v) as mobile phases. In the frames of the present project we also studied the thermodynamics of chiral separation.
Fludarabine phosphate (FDB), an adenine nucleoside analog, is an antimetabolite with anticancer effect attributable to its inhibitory effect on DNA and RNA synthesis. A sensitive voltammetric technique has been developed for the determination of Fludarabine using amine-functionalized multi walled carbon nanotubes modified glassy carbon electrode (MWCNTs-NH2/GCE). The NH2-MWCNTs/GCE exhibited a considerable enhancement effect to the voltammetric response of FDB due to electrocatalytic performance. In silico studies provided us to elucidate the visualization and chemical differences in fludarabine-specific molecular interactions with carboxyl – and amine-functionalized multi walled carbon nanotubes modified glassy carbon electrode.
The electrochemical behavior of FDB at MWCNTs-NH2/GCE was investigated using cyclic voltammetry, adsorptive stripping differential pulse voltammetry (AdSDPV) and adsorptive stripping square wave voltammetry (AdSSWV) in a wide pH range. Cyclic voltammetric investigations emphasized that Fludarabine is irreversibly oxidized at the NH2-MWCNTs/GCE. The mixed diffusion-adsorption controlled electrochemical oxidation of Fludarabine revealed by studies at different scan rates. The kinetic and thermodynamic parameters of FDB have been investigated via changing temperatures.
The experimental parameters, such as pulse amplitude, frequency, deposition potential optimized for square-wave voltammetry. Under optimum conditions in phosphate buffer (pH 2.0), linear calibration curve was obtained in the range of 2.00 10-7M – 4.00 10-6 M solution using adsorptive stripping square wave voltammetry. The limit of detection and limit of quantification were calculated 2.90 10-8M and 9.68 10-8M, respectively. The proposed nanosensor is a feasible alternative for direct measurements of FDB in pharmaceutical samples by fast and sensitive AdSSWV. This study promotes the potential application of NH2-MWCNTs based materials in the design of electrochemical sensors for drug analysis in the clinical chemistry.
Dihydroxypropyl theophylline (DPT), which helps to increase bronchial diameter by providing bronchodilatation with phosphodiesterase inhibition, is used in the treatment of respiratory diseases.
A sensitive voltammetric technique has been developed for the quantification of DPT in pharmaceutical dosage forms and biological samples using boron doped diamond electrode (BDDE).
The oxidation mechanism of DPT was investigated using glassy carbon electrode (GCE) and BDDE by cyclic, differential pulse and square wave voltammetric techniques in the supporting electrolytes which acetate, phosphate and borate buffers in the pH range 1.80 - 12.28. The scan rate studies of DPT was carried out using both working electrodes by cyclic voltammetric technique in pH 8.02 phosphate buffer. According to the scan rate studies, the oxidation reaction of the DPT was found to be irreversible and diffusion controlled process using BDDE. The oxidation mechanism of DPT was compared with the model drug Caffein.
The experimental parameters, such as pulse amplitude, frequency, deposition potential for the square wave voltammetry technique were optimized in pH 8,02 phosphate buffer by BDEE.
The determination of DPT was performed by square wave voltammetry using BDDE electrode in pH 8,02 phosphate buffer. The developed method was applied to the pharmaceutical dosage form of DPT. In addition, the developed method was applied for biological samples (urine & serum) and recovery studies were performed. LOQ values were found to be 1,28x10-6 for human urine and 1,31x10-6 for human serum. The recovery values were found to be between 99.5% and 101.9% for commercial drug in ampoule form; 99.0% - 100.9% for human urine and 99.3% - 102.2% for human serum. The developed method was fully validated according to ICH Guidelines.
Modafinil is a wakefulness promoting agent was initially investigated for the treatment of excessive daytime sleepiness associated with narcolepsy and fatigue. Modafinil is BCS-Class II drug, of low solubility and high permeability. Crystalline structure and particle size of the drug plays a major role in bioavailability. In a previous work, a double slugging technique was used to develop a new formula using coarse particle size possessed similar dissolution behavior as well as being bioequivalent to the original brand modafinil tablets (Provigil®). In this work, Microwave and Ultrasonic energy were used to change the lattice and crystalline structure of modafinil coarse particles. The compressibility and compactibility, intrinsic dissolution, XRPD, FTIR and DSC were utilised for physicochemical characterisation of modafinil crystalline powder before and after treatments with ultrasound and microwaves. The preliminary results of dissolution, DSC and XRPD showed a significant difference between modafinil samples before and after exposure to ultrasound or microwaves. Tablets of treated or untreated modafinil were prepared and tested for dissolution behaviour. A significant increase in rate was shown with tablets containing treated dug crystals.
In recent years organometallic compounds have been used in medicinal chemistry as antineoplastic and antimicrobial agents. In present work, we evaluated antimicrobial properties of ferrocene-boronic acid, which is synthetic organometallic compound and contains unique physical and chemical properties of ferrocene and boronic acid groups, against pseudomonas aeruginosa. In bacteri culture, 8 μg /mL ferrocene-boronic acid solution was added and incubate for 18 hours. We used regular flow UPLC/MS based proteomics approach to understand mode of actio of ferrocene-boronic acid over pathogen. We extracted proteins and digested with trypsin enzyme. Peptides were analyzed in LC/Q-TOF/MS system at 0.200 mL/min flow rate. Auto MS/MS mode was used to record MS/MS data of peptides. Recorded MS/MS data was procesed in Maxquant proteomics platform. Control and ferrocene boronic acid treated groups were compared to find differentially expressed proteins and induced pathways. In our work, we found that 132 proteins were altered under ferrocene boronic acid stress condition. Functional classification results showed that ferrocene boronic acid is very effective over metabolic processes. Moreover, ferrocene boronic acid affects DNA replication process. Mode of action of ferrocene boronic acid is similar with floroquionolne antibiotics. In addition, we tried to understand resistance mechanism in pseudomonas aeruginosa against ferrocene boronic acid. We found that various mechanisms like reduced permeability in outer membrane was observed. Our results showed that ferrocene boronic acid could be evaluated as antimicrobial agents and our findings will contribute using of organometallic compounds in medicinal chemistry.
The presence of heavy metal ions in natural resources like water and soil is of great concern over the last few decades because of their toxicity, very low degradability and carcinogenic nature to the living organism . Among heavy metals, Zn2+ is very commonly found metal ion in water bodies. Though Zn2+ is a very important micronutrient for human health, its presence above the permissible limit of 5 mg/L creates a lot of health issues like anemia, skin irritation, vomiting, stomach problems, etc. . The primary sources of Zn2+ ion in wastewater are metal processing, brass, iron and steel plants, paint, galvanizing and rubber industries, pulp, paper, etc. Over the last few decades, various physicochemical methods are in practice to minimize the Zn2+ concentration in the final effluent discharge into the environment. The commonly used treatment methods are chemical precipitation, ion exchange, electrokinetic membrane technology and adsorption .
In this study, sulfonated graphene and reduced graphene oxide materials were prepared [4-5] to examine the heavy metal adsorption capacity and mechanism. The microstructure and morphology of the graphene-based samples were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) equipped with an Energy-Dispersive X-ray Spectroscopy (EDX) mapping. Zinc (Zn2+) was selected as adsorbate to study the different adsorption mechanism and site contributions of synthesized graphene-based materials. Adsorption mechanism of Zn(II) ion on adsorbents from kinetic and isotherm models was explained.↑
Acknowledgement: The authors gratefully acknowledge financial support from the Van Yuzuncu Yil University Scientific Research Foundation
(Project ID: FAP-2019-8244)
Zinc coatings are most popular anticorrosive protection of steel construction. Zinc due to its physicochemical properties, location in electrochemical series and low cost is a great alternative to other kinds of corrosion protective materials. Javanbakht et al. observed positive influence of reinforcement of Zn matrix by SiC nanoparticles resulting in shifting of corrosion potential values towards more electropositive range. Reported Zn-SiC composites were deposited at pulsed current conditions and electrolyte was additionally stirred to ensure homogenous distribution of reinforcing particles in electrolyte volume . Properties of composite coatings depend of numerous factors such as: current density, bath composition, concentration and size of reinforcing phase, presence of brighteners, temperature and stirring intensity . Kinetics of ceramic particles incorporation process is influenced also by type and size of reinforcing particles. Positive effect visible in increase of particles incorporation rate is usually observed at increased particles concentration but concentration increase resulting in particles coagulation . Application of ultrasounds during electrolysis may result in decrease of susceptibility of particles for aggregation influencing homogenous distribution of reinforcing particles in metal matrix. Homogeneity of layers guarantee an increase of microhardness values as well as abrasion resistance .
Main objectives of performed studies were focused on the development of technology for sonoelectrochemical coating of composite anticorrosive Zn films reinforced by SiC nanoparticles and optimization of synthesis parameters towards their functional properties. Investigations were performed with the use of modified commercial acidic electrolyte. Optimization of composite coating process was performed under current controlled conditions (constant current, pulsed current) without and at the presence of ultrasounds agitation. Coatings deposited at pulsed current as well as constant current conditions were characterised towards their composition, structure, reflectivity and morphology. An influence of ultrasounds as well as current conditions on coatings deposition rate, current efficiency was also investigated.
This work was supported by National Centre for Research and Development (grant No. LIDER UMO-2017/26/D/ST8/00508).
 M. Javanbakht, A. Mozafari, H. Omidvar, (M. Sajjadnejad), Preparation and corrosion resistance of pulse electrodeposited Zn and Zn-SiC nanocomposite coatings, Applied Surface Science 300 (2014) 1-7.
 T. Bellezze, R. Fratesi, (G. Roventi), Electrodeposition of Zn-SiC nanocomposite coatings, Journal of Applied Electrochemistry 43(8) (2013) 839-846.
 (C.T.J. Low), R.G.A. Wills, F.C. Walsh, Electrodeposition of composite coatings containing nanoparticles in a metal deposit, Surface and Coatings Technology 201(1-2) (2006) 371-383.
Monocyclic and bicyclic pyrimidinium betaines were synthesized by condensation of 2-aminopyridine or N, N’-disubstituted amidines with substituted malonic esters, yielding mesoionic structures. Their structures were confirmed by UV, IR, NMR and MS analyses. The effect of relevant factors on the betaines synthesis was studied. It was investigated the effect of the concentration, the reaction time and the solvent on the Synthesis of these compounds. From the results obtained, we noted that betaine yields increases by increasing the amount of malonic ester. These yields are lower in the case of monocyclic betaines.
We performed the synthesis reaction in two different aprotic solvents (acetone and diethyl ether). We noticed that the nature of the solvent has a significant effect on the yield of monocyclic betaines. This yield is better in the case where diethyl ether is used. On the other hand, the nature of the solvent does not affect the yield of bicyclic betaines. We have also used other solvents; among others Methylene chloride and we have found that the precipitation of monocyclic betaine is very difficult in the reaction medium. We carried out the synthesis of monocyclic betaine in diethyl ether at varying times. The results showed that a longer reaction time is an unfavorable factor, whereas a shorter time (30-60 min) leads to a better yield of monocyclic betaine.
The problem of depletion of "traditional" sources of hydrocarbons with high porosity and permeability forced scientists all over the world to pay attention to "unconventional" or hard-to-recover resources. In the most famous unconventional reservoirs clay and siliceous rocks predominate, which have low porosity and extremely low permeability. The Bazhenov formation and the Domanik horizon, which are classified as oil shale, are important for Russia. Most of the organic matter (OM) of high carbon Domanic sediments is in the resin-asphaltene components, as well as in kerogen, which is an insoluble part of OM, containing mainly chemically tightly bound components inside the rock. Kerogen is converted to hydrocarbons only at temperatures above 100°C. Known methods for studying the organic matter of oil source rocks (pyrolysis by the Rock-Eval method, IR spectroscopy, GC-MS, etc.) require continuous and time-consuming sample preparation and analysis procedures, and it is difficult to completely remove the rock matrix when isolating kerogen.
In this work the capabilities of Fourier transform infrared (FTIR) spectroscopy for the structural-group analysis of oil shale organic matter directly in the low-permeable reservoir and for assessing its oil-generating potential were shown. FTIR spectra of the rock samples were performed in the diffuse reflectance, the attenuated total reflectance (ATR) and the transmission (in KBr pellets) modes.
In ATR spectra of rocks, two broad peak can be distinguished in the region of 1400 and 1000 cm⁻¹, which correspond to vibrations of Si–O, CO, C=O, Al–O, and Fe–S bonds in the known minerals of the sedimentary complex, as well as CH₂ and CH₃ bending modes of aliphatic groups and C=C stretching of aromatic fragments. According to ATR-FTIR spectra in the long-wavelength region (700 – 900 cm⁻¹), rock samples are characterized as having a more complex composition. After carbonate dissolution, ATR spectra change noticeably: instead of a broad peak in the 1400 cm⁻¹ region CH₂ and CH₃ bending modes (1375 and 1454 cm⁻¹) in acyclic and cyclic structures, the aromatic ring C=C stretching (1630 cm⁻¹), symmetrical CH₂ stretching (2850 cm⁻¹), asymmetrical CH₂ stretching (2920 cm⁻¹) and asymmetrical CH₃ stretching (2950 cm⁻¹) bands appear. FTIR spectra of rocks in the transmission mode (KBr pellets with 0.1% rock) have more resolved peaks compared to ATR spectra. This increases the accuracy of the structural-group analysis of the OM in rocks, but sample preparation takes a lot of time compared to ATR method.
The evaluation of the applicability of IR spectroscopy in assessing the oil-generating potential of rocks and the maturity parameters of OM in kerogen was performed by comparing spectral coefficients (aromaticity, branching and aliphaticity) characterizing the structural group composition of the studied products and standard pyrolysis parameters (S1 - oil hydrocarbons; S2 - kerogen cracking products and resin-asphaltene components; TOC - total organic carbon). In a narrow interval of sampling depths with decreasing TOC, S1 and S2 parameters, a noticeable decrease in the aromaticity coefficient and, conversely, an increase in the aliphaticity coefficient were observed. This can be used in the rapid assessment of OM in reservoir.
|Absorption bands, cm-1||Organic matter vibrations||Mineral rock vibrations|
C–H deformation region
|Si–O quartz, montmorillonite, kaolinite, silicate
С−O and С=O dolomite, calcite
|1370-1450||CH2 and CH3
|С−O and С=O dolomite, calcite, aragonite|
|1600-1630||aromatic ring C=C stretching||С=O dolomite|
|2800-3000||aliphatic C–H stretching region||-|
Gasification is regarded as one of the most promising options for utilizing biomass. The biosyngas can be produced from biomass using gasification. The biosyngas can be not only directly used in gas turbines for power generation but in recent years more and more often also catalytically converted into Fischer–Tropsch (FT) oils or other chemical products.
FT catalysts are particularly sensitive to the presence of impurities in the reaction feed. Thus, purification of the syngas is an important and often very expensive part of the whole technology. The presence of various impurities and poisons specific of biosyngas and gasification process such as tar, particulates, ammonia, hydrochloric acid and sulphur gases can strongly affect the performance of cobalt and iron FT catalysts. Among these impurities, nitrogen compounds may cause irreversible deactivation of FT catalysts.
Solid phase adsorption (SPA) method was initially developed to measure tar compounds ranging in molecular weight from benzene to coronene. The SPA, commonly used for tar measurements, can also be used for similar compounds containing nitrogen. In this study, a modified sampling device containing 500 mg of amino-phase sorbent and 100 mg of activated coconut charcoal was chosen.
Knowing the popular nitrogen organic compounds of biomass tar, four compounds, Pyridine, Pyrrole, Benzonitrile un Quinoline were selected for study. A stock solution was made in dichloromethane. Desorption and adsorption efficiencies of the tar compounds on amino-phase sorbent and on activated coconut charcoal were studied.
Desorption efficiency of Pyridine, Pyrrole, Benzonitrile un Quinoline by dichloromethane from the amino phase adsorbent, and desorption efficiency of the same compounds by carbon disulfide from the activated coconut charcoal were analysed. For this, stock solution was injected into the front adsorbent section of each adsorbent cartridge with a micro liter syringe, then air was drawn through adsorbent cartridges so that compounds would evenly spread across the adsorbent. Desorption was then carried out in two ways: from amino phase adsorbent compounds is eluted with dichloromethane, from activated coconut charcoal – with carbon disulphide.
Adsorption efficiency of Pyridine, Pyrrole, Benzonitrile un Quinoline on amino phase adsorbent and on activated coconut charcoal was explored. For this, definite volumes of stock solutions were injected into the short piece of heated glass tube installed in front of the consecutively joined adsorbent cartridges. Air was drawn through the tube and both adsorbent cartridges loaded with amino phase adsorbent and activated coconut charcoal with the help of an air pump. Research that has been carried out indicated that Pyridine, Pyrrole, Benzonitrile un Quinoline get completely adsorbed on the first adsorbent, amino phase one, and, hence, do not reach the activated coconut charcoal.
Adsorption efficiency is calculated in as a ratio of the mass of the compound collected on a sorbent to the total mass of this compound in the gas that was drawn through the sorbent column. Desorption efficiency of a compound is taken into account when calculating its adsorption efficiency. Adsorption efficiency on amino phase adsorbent of Pyridine is 98.49±2.45, Pyrrole – 98,10±1.69, Benzonitrile – 94,80±3.04, and Quinoline – 94.96±1.72.
During the group analysis of oil products, foodstuff, natural waters and other real objects, the total content (cΣ) of similar analytes is expressed recalculated to a standard substance Xst. Their summary signal AΣ is usually measured without separation. For example, AΣ is light absorbance of a sample at a certain wavelength. Then the total index (TI) is calculated as с* = АΣ/Kst. Here Kst is the sensitivity coefficient for Xst and c* is the numerical value of TI, which is supposed to be equal the required cΣ. TIs examples can be provided by phenolic and hydrocarbon indices of waters, total antioxidant activity of wines, total protein of urine, etc. . Such methods are widely used but metrologically incorrect and lead to high uncertainty of results . Recently we have elaborated the algorithm to estimate cΣ without recalculating to Xst. The algorithm takes into account different sensitivity coefficients for all the analytes of the studied type (intragroup signal’s selectivity). No information on the nature of analytes in the investigated sample is required. When modelling deviations of c* from cΣ, the following assumptions were accepted: 1) the group has to include analytes X1, X2, X3 …. Xm, similar in structure and/or their functional qualities and contributing to the formation of AΣ; 2) the summary signal linearly depends on the concentration of each Xi, AΣ is additive and is not formed by alien components; 3) sensitivity coefficients Ki are known for all Xi, and 0 < K1 ≤ K2 ≤ …≤ Km; 4) Kst is determined by the same procedure, K1 ≤ Kst ≤ Km; 5) the errors determined by all factors except for the differences in the sensitivity are negligible. Within this model we have obtained two equivalent inequalities to estimate cΣ value. The width of possible values interval (∆c) objectively characterizes the systematic component of total uncertainty of results; it is independent of Xst choice and strongly exceeds the width of traditional confidence intervals (Student’s or Laplace’s estimates). The accuracy of new estimates was checked by the analysis of various model mixtures using several methods of signal measuring . Accurate and rather narrow (∆c < 0,5 cΣ) estimates of total content can be obtained if 1 < Km/K1 < 1,3. In other cases values of ∆c are too high. The only method to minimize ∆c is the intragroup selectivity reducing, for example, with multiple wavelength measurements [4,5]. In this report the new data will be presented, namely the estimates of total content of similar analytes (phenolics, arenes etc.) in foodstuff, natural waters, sewages and other real objects.
1. Baena J.R., Valcarcel, M. Trends Anal. Chem., 2003, 22 (10), 641.
2. Vershinin, V.I., Talanta, 2015, 131 (1), 293.
3. Vershinin V.I., Isachenko N.V., Brilenok N.S. J. Anal. Chem., 2016, 71 (4), 351.
4. Vershinin, V.I., Petrov S.V. Talanta, 2016, 148 (1), 163.
5. Vershinin V.I. Determination of similar substances total content (Theory of total indices). Monograph in Russian. Omsk, OmSU, 2016. – 288 p.
pH is one of the most frequently measured analytical quantities. Arrhenius, Brønsted, and Lowry defined acids as proton donors and bases as proton acceptors, a concept nowadays known as Brønsted acidity. This concept is used in all chemistry-related areas including: materials science, energy storage, catalysis, environmental science, and molecular biology. In aqueous solution, Brønsted acidity is expressed quantitatively as the pH value (referred to here as “conventional pH value”) that is pH = -log a(H⁺), with the activity of the hydrated proton a(H⁺) given in mol/kg. Within one homogenous medium, pH differences are proportional to electrochemical potential differences and thus directly connected to a thermodynamic definition. Every solvent has its own pH scale and due to unknown shifts of zero points of these scales, pH values in different solvents are incomparable. The concept of the unified pH scale has been proposed to define and compare acidities of any medium, in principle in any phase. It is based on a single universal reference point – absolute chemical potential of hydrogen ions in the gas phase – which is the same, regardless of medium.
Equations of absolute pH value expressing acidities in terms of chemical potentials, pHabs, and pH values in any other solvent/medium can be directly compared to the well-known aqueous pH scale, pHabs,H₂O, are as seen in Eq.1 and Eq.2. Moreover, the differential measurement cell with salt bridge below has been used for these kind of measurements due to ease of application as seen in Figure 1.
The notion pHabs,H₂O means that pH is expressed on the absolute scale, but values are shifted by a constant (−193.5 pH units at 25 °C) in order to make the pHabs values directly comparable to the conventional aqueous pH values.
Because the conventional pH scale remains restricted to dilute aqueous solutions. The non-trivial interconversion between solvent-specific pH scales has real implications for the biofuel (e.g., pHe scale), oceanographic (e.g., pHT scale) and liquid chromatography user communities. A revolutionary new definition of pH has between proposed, the pHabs scale, which can be employed in all solvents, and its associated pHabs,H₂O scale (the pHabs scale referenced to water) allows an intuitive understand of these new pH values for those familiar with the conventional pH scale.
The non-isothermal Thermogravimetric method was used for the analysis of Coal-biomass blends, the blends were mainly consisting of Sugarcane Bagasse-Coal blend, Rice Husk-Coal blend and Wheat Straw-Coal blend and optimum conditions were determined for their use as energy source providing an economical solution of gasification and combustion problems in Pakistan. Sampling of the pure biomass was done from different areas and proximate analysis was conducted to measure their volatile matter, ash content and fixed carbon using 1g of each sample. Calorific value was then determined using the bomb calorimeter and particle size was then measured using Particle Size Analyzer. Coal-Biomass blends were prepared in different ratios and Thermogravimetric analysis was done under air atmosphere at same heating rate (25°C/ min up to 950°C). The particle size of biomass samples was 250µm (60 mesh). Residual weight is a function of heating rate and increases with heating rate. The rate of weight losses was increased with increases in biomass for all coal-biomass blends studied. Residual weight % was obtained for coal, wheat straw; rice husk and sugar cane bagasse were 46.05, 12.3, 9.29 and 4.3 respectively. The weight of biomass increased, maximum rate of weight loss (% per min) also increased for all biomass blends samples. Comparison between maximum rates of weight loss % per min of sugar cane bagasse, wheat straw and rice husk depicted that maximum rate of weight loss % per min of sugar cane bagasse was maximum as compared to wheat straw and rice husk. This was due to the presence of high volatile matter in sugar cane bagasse biomass.
Higenamine, also known as norcoclaurine, is a plant alkaloid and is considered to be one of the most important components in some plant species. Higenamine is a critical agent both as a therapeutic and pharmacological features in traditional medicine as well as nowadays an active ingredient in dietary supplements [1,2]. There are quite a limited number of research articles on higenamine analysis from different matrix environments. Almost all of these studies were carried out by separation-based methods. Hence, developing new analytical methods which are able to rapid and simple quantification of higenamine are highly needed.
In the present paper, a cheap, rapid, simple and modification-free electroanalytical methodology based on the pretreated pencil graphite electrode is described for the detection of higenamine. Higenamine yielded two well-defined cyclic voltammetric responses in 0.1 mol L-1 Britton-Robinson (BR, pH 4.0) buffer at +0.44 and 0.91 V (vs. Ag/AgCl), respectively. The experimental results show that the oxidation peaks of higenamine are strongly dependent on pH value of the solution. Using the optimal square-wave voltammetric (SWV) conditions the first oxidation peak (0.43 V) was used to quantification of higenamine. Linearity was found between the oxidation peak currents and the concentration of higenamine within 0.05 to 2.0 μg mL-1 (1.84×10-7-7.37×10-6 mol L-1), with a detection limit of 0.014 μg mL-1 (5.16×10-8 mol L-1). The relative standard deviation (RSD) was 7.49% at the 0.05 μg mL-1 level (n=10). As an example, the practical applicability of the pretreated pencil graphite electrode was tested with the measurement of higenamine in the commercial dietary supplement formulations.
Acknowledgement: The authors gratefully acknowledge financial support from the Van Yuzuncu Yil University Scientific Research Foundation (Project ID: TAP-2019-8081).
An electroanalytical methodology for the determination of As(III) in bivalve mollusks using a glassy carbon electrode modified with gold nanorods (AuNRs) deposited on electrochemically reduced graphene oxide (ErGO) using square wave anodic stripping voltammetry (SWASV) has been developed. The AuNRs were synthetized by a multistep seed-mediated growth and characterized by UV-Vis spectroscopy and transmission electronic microscopy (TEM). The modified electrode (GC/ErGO/AuNRs) was characterized by cyclic voltammetry and scanning electronic microscopy (SEM). The optimum conditions for the modified electrode were as follows: supporting electrolyte HNO3 (1 mol L-1), accumulation potential (Eacc) = −0.6 V and accumulation time (tacc) = 120 s. A linear range was observed from 2 to 60 µg L−1 with a limit of detection (LOD) of 0.25 µg L−1. The proposed procedure was validated with TMDA-64.2 and TM-28.4 Certified Reference Materials, and it showed good accuracy and reproducibility. The methodology was applied to samples of bivalve mollusks with satisfactory results, allowing to perform sensitive analyses in the detection of arsenic in marine resources.
Sample pretreatment plays a key role in chemical analysis. As usual, it includes the separation or preconcentration of the analytes from the sample matrix with the improvements of selectivity and sensitivity. To eliminate the negative effect of matrix components, various sample pretreatment techniques are usually applied in analyses of complex samples. Liquid-liquid microextraction (LLME), that probably, is one of the most common sample preparation techniques, has its indisputable advantages such as simplicity, reliability and adaptability to a wide variety of sample types and analytes, as well as, compatibility with majority of analytical instruments. This report highlights some of the
most important developments in homogeneous LLME. Recent applications of homogeneous LLME are also presented.
Authors gratefully acknowledge the Russian Science Foundation (project no. 16-13- 10117) for financial support.
Carbon materials, in particular graphite, continue to be the top choice when fabricating anodes for lithium-ion batteries. In spite of extensive electrochemical studies dealing with carbon materials, the chemical composition of the electrodes in energy storage systems often unknown. At present, the need to obtain elemental analysis information concerning these electrodes, as well for other components of batteries, has started to be highlighted1. Attending to that, simple, fast and reliable methodologies that can provide chemical composition with a high level of confidence are needed. Possibly at the forefront of these techniques are spectroscopic tools such as inductively coupled plasma-optical emission spectrometry/mass spectrometry (ICP-OES/MS). This a so-called “bulk” technique, where the entire volume of a batch sample is analyzed. By contrast, superficial X-ray photoelectron spectroscopy (XPS) or the more localized energy-dispersive X-ray spectroscopy (EDS) can be misleading in regards to the chemical composition of carbon nanomaterials as they probe limited sample volumes. However, when considering ICP-OES/MS, a requirement must be accomplished: a liquid homogeneous suspension. This implies that the carbon network must be destroyed2. Recently, we proposed alkaline oxidation (or fusion) as a viable means to prepare a certified reference material of single-wall carbon nanotubes, namely the SWCNT-1,3 for ICP-OES. In that study, satisfactory recoveries of the transition metal catalysts used during the synthesis of the nanotubes were obtained.
In this work, we extend the alkaline oxidation approach to other commercial carbon materials. This method allowed the determination of several elements with a good level of confidence. To shed light into the possible influence of the alkaline salt on the carbon lattice, structural and morphological analysis were made of the pristine carbon materials and their fused residues. Solid-state nuclear magnetic resonance studies showed that there is no interference of the lithium borate and that, instead, an efficient combustion of the carbon took place.
1.Nowak, S.; Winter, M., Elemental analysis of lithium ion batteries. Journal of Analytical Atomic Spectrometry 2017, 32 (10), 1833-1847.
2.Simoes, F. R.; Batra, N. K.; Warsama, B. H.; Canlas, C. G.; Patole, S. P.; Yapici, T. F.; Costa, P. M., Elemental Quantification and Residues Characterisation of Wet Digested Certified and Commercial Carbon Materials. Anal. Chem. 2016, 11783-11790.
3.Simoes, F.; Batra, N. M.; Emwas, A.-H.; Costa, P. M. F. J., Validation of alkaline oxidation as a pre-treatment method for elemental quantification in single-walled carbon nanotubes. Analytical Methods 2019.
Toxic heavy metals are one of the most common contaminants likely to be found in herbal materials and herbal products. They are of special health concerns due to their potential toxic effects even at low concentration. In Singapore, Chinese Proprietary Medicines (CPM) must comply with the legal permissible limits for 4 heavy metals (Hg, As, Pb and Cu at 0.5, 5, 20 and 150 ppm respectively). Cadmium is listed under the ASEAN Guidelines on limits of contaminants for traditional medicines and health supplement with a limit of 0.3 ppm.
Due to the limitation of conventional microwave digestion systems, samples may have to be digested using different digestion methods for the determination of various elements. Typically, milder conditions are used for volatile elements. However, some sample matrices might not be completely digested under such conditions, leading to lower results or matrix interference in Inductively Coupled Plasma Mass Spectrometry (ICPMS) during analysis. As such, a single digestion method that allows the analysis of multiple elements with different volatility will largely reduce the laborious work and reagents needed compared to separate methods using conventional microwave digestion system. This can be achieved using the UltraWAVE Single Reaction Chamber (SRC) technology. Unlike conventional system, there is no concern over building up of pressure within the digestion vials as the UltraWAVE system operates in a way that the internal pressure of the digestion vials is the same as the external pressure.
This project is to develop and validate a 4-in-1 Heavy Metal Analysis for As, Cd, Hg and Pb which include (1) a digestion method that can completely digest CPM samples using the UltraWAVE microwave digestion system, and (2) a quantification method using ICPMS.
Today much attention has been paid to the creation of fluorescent dye capable of effectively detecting various substances. Our recent investigations have been focused on obtaining novel organic fluorophores such as N containing benzanthrone derivatives. Previously we have synthesized new polarity sensitive luminescent 3 amidino and 3-aminobenzanthrones with various substituents. Fused azaheterocyclic derivatives of benzanthrone almost are not described in literature. For this reason, the present work focuses on the characterization of newly synthesized triazoles. This class of heterocyclic derivatives has stimulated great interest from synthetic and medicinal chemists because triazoles are also heterocyclic targets of considerable importance in the pharmaceutical sector. This heterocyclic moiety is present within the core structure of numerous drugs. This research covers synthesis of new triazoles from nitrobenzanthrones. One of reactions with sodium azide in DMSO resulted in a product with strong red fluorescence, as well as few byproducts with yellow and orange fluorescence. These new compounds are characterized by high chemical stability, large Stokes shift, polarity sensitive emission, good fluorescence quantum yields.
The obtained compounds have been characterized by mass-spectroscopic and chromatographic methods. Sample preparation: approximately 2 mg of each compound were suspended in 1 mL of chloroform, for analysis 1 µL of these solutions were injected into the GC–MS system. The electron ionization mass spectra were obtained with a Shimadzu GCMS-QP2010. MS parameters: the electron ionization energy was 70 eV, the scan range was m/z 50–500. Mass spectra of newly synthesized triazoles showed, that the EI-MS predominated base peaks matches with the theoretical molecular weight. Fragmentation mechanisms of investigated substances are studied and discussed.
Formaldehyde is one of the most relevant indoor air pollutants, due to its carcinogenic and toxic properties and the fact that it is commonly applied in the production of adhesives and resins for wood-based products . Due to the hazardous effects of formaldehyde in health, it is necessary to accurately measure its content in different materials, in particular in indoor building materials. For a long time, since it was introduced by Nash and co-workers , the acetylacetone reaction has been one of the best options for formaldehyde derivatization. The reaction of formaldehyde with acetylacetone, in the presence of excess ammonium salt, forms 3,5-diacetyl-1,4-dihydrolutidine (DDL), which has a yellow colour that can be spectrophotometrically determined at 412 nm. Acetylacetone is mostly used due to its high selectivity towards formaldehyde. This derivatization approach is present in different European and international standard procedures for the determination of formaldehyde in wood-based products, such as in EN 717-3 and ISO 12460-5 .
A membraneless extraction module (MLEM) was used for the extraction of formaldehyde directly from wood-based samples. MLEM, developed after gas-diffusion microextraction (GDME) , is a simple and efficient sample preparation technique for volatile compounds, aiming their headspace extraction.
In this work, we assess the stability of the formaldehyde-acetylacetone derivative (DDL) over a defined period of time. Kinetic studies were performed by continuously measuring the absorbance at 412 nm over extracts obtained from the MLEM extraction of wood-based products. Different parameters and its influence on the derivatization reaction were evaluated, such as the temperature of extraction, derivatization temperature or the spiking of the sample. After a suitable optimization procedure, the methodology was used for the determination of the formaldehyde content in different wood-based products.
RMR would like to acknowledge Fundação para a Ciência e a Tecnologia (FCT, Portugal) for the Junior Research fellowship CEECIND/04259/2017. The work was also supported by UID/QUI/50006/2019 with funding from FCT/MCTES through national funds.
 P. F. Brandão, R. M. Ramos, J. A. Rodrigues, Analytical and Bioanalytical Chemistry, 410 (2018) 6873
 T. Nash, Biochemical Journal, 55 (1953) 416
 P. F. Brandão, R. M. Ramos, I. M. Valente, P. J. Almeida, A. Carro, R. Lorenzo, J. A. Rodrigues, Analytical and Bioanalytical Chemistry, 409 (2018) 2885
 R. M. Ramos, J. G. Pacheco, L. M. Gonçalves, I. M. Valente, J. A. Rodrigues, A. A. Barros, Food Control, 24 (2012) 220
A simple and rapid separation procedure has been systemized for the determination of 90Sr in the radioactive stainless steel samples with high chemical recoveries and effective removal of matrix interferences. The radioactive stainless steel samples were from biological shielding concrete. The samples were loaded on DGA + LN extraction chromatographic resins to remove interfering elements.The interfering elements Eu、Ni、Co、Cs、Ag、Sr were sufficiently removed, the chemical recoveries of Y were stable and high, ranging from 90.0% to 106.3%,with an average value of 95.8±2.7% (n=12).The accuracy of 90Sr determination was validated by the analysis of Spiked amount of 90Sr with 0.276Bq,1.38Bq and 9.66 Bq,then Beta source preparation was accomplished by filtrating the Y2(C2O4)3•9H2O precipitate through a 25 mm filter paper and 90Y measurements were carried out by a low level α,β counter, the difference between determined 90Y activity (Bq) and spiked amount of 90Y (Bq) was from -1.8% to 2.1%,while Y chemical recovery was from 90.0%～106.3%. 90Sr is calculated through 90Y.The MDA of 90Sr was calculated to be 15.0 Bq/kg, while the stainless steel for reusing is 90.0Bq/g in the Chinese standard GB/T 17567-2009. Finally, this method was successfully applied to quick analysis of Strontium-90 in radioactive stainless steel samples from a research reator.
From personal experience of analyzing refined precious metals by means of ICP-OES it is known that analytical emission lines of impurities behave differently, depending on the base metal’s concentration in solutions. Previous study on refined palladium allowed interesting observations and showed certain patterns of behavior for atomic and ionic emission lines. The present study on refined platinum is a next logical step.
A batch of solutions of Ag, Au, Cu, Ir, Ni, Pd, Ru (5 mg/l each) was prepared, with different Pt concentrations: 0; 0.5; 1; 2; 3; 5; 7, and 10 g/l. Relative intensities I/I0 were plotted against Pt concentrations (I=I0 for the solution without platinum), for each impurity. Dependence on Pt concentration for some emission lines is shown on the figure.
Overall, behavior of emission lines for Pt solutions is quite similar to one for Pd solutions. Namely, intensities of emission lines generally fall as C(Pt) grows, and intensities of the ionic lines fall faster. However, two differences should be noted: 1) This effect is about twice less pronounced as in the case of refined Pd; 2) Ionic line of Sc 354,634 nm is more stable that all atomic lines of other studied impurities.
This data could be useful for analysis of refined platinum if for some reasons it is impossible to use standard solutions containing platinum. The differences between Pt and Pd cases are to be discussed.
For the first time, the dependence of the redox potential change during the reaction of peroxyl radical’s generation and their interaction with antioxidants was studied. A regular change of the potential is due to oxidation of an antioxidant by initiating peroxyl radicals, accompanied by electron transfer. The original direct method for determining induction periods, inhibition coefficients and antiradical capacity using the potentiometric method is proposed. Using the proposed approach induction periods and inhibition coefficients of various model antioxidants were determined. The antiradical capacity of herbal extract and tea was studied. A high degree of correlation with the DPPH method and the Folin-Ciocalteu method were obtained. RSD results obtained using the proposed approach do not exceed 7%. Perspective class of double acting compounds 6-nitro-1,2,4-triazoloazin containing fragments of polyphenols with antiviral activity were investigated.
|АО||τ, min||f||TAC,10(4) mM-eq||RSD, %|
Parabens are esters of p-hydroxybenzoic acid, which are widely employed as preservatives in personal care products, pharmaceuticals and food. Because of their fast absorption rates and metabolization to less toxic p-hydroxybenzoic acid, parabens had been used at high concentrations at first. Also some specialities such as broad spectrum of antibacterial activity, chemical stability over a wide pH range and low costs made parabens to be used widely with methyl paraben, ethyl paraben, propyl paraben, and butyl paraben as the most employed types. However some studies revealed that parabens might disrupt endocrine system by exhibiting weak estrogenic and other hormone-related activity at higher doses than the permitted levels. Exposure to parabens may also cause breast cancer and negative reproductive effects.
One of the exposure ways to parabens is the personal care products possessing high paraben concentrations. Considering the side effects many countries regulated maximum permitted levels of parabens that could be used in cosmetics, which are 0.4% (w:w) for each of the used paraben species and 0.8% (w:w) for total concentration when a mixture of parabens are employed in the European Union guidelines.
The negative impacts of parabens on human health leads to the need of reliable analytical methods. Several techniques have been used for paraben analysis such as HPLC, UHPLC, GC, CE with different detectors of UV, DAD, MS, and etc. among which HPLC is the most common method. Sample preparation prior to analysis is also a very critical step in determination of parabens because of the low concentration levels and complex sample matrices. Liquid-liquid extraction and solid phase extraction are two of the traditional pretreatment methods with some disadvantages as requirement of large volumes of sample and extraction solvent and being time consuming. Dispersive liquid–liquid microextraction (DLLME) is one of the recently developed techniques to overcome those disadvantages which is based on the extraction of the analyte by an immiscible extracting solvent and a disperser solvent. The disperser solvent that can be dissolved in both of the phases increases the contact between the immiscible liquids. A specific technique of DLLME, ultrasound and vortex-assisted dispersive liquid–liquid microextraction (USVADLLME) reduces the required volume of the extracting solvents which generally have serious toxic effects like the chlorinated solvents. In USVADLLME ultrasonication provides a dispersed phase for the quantitative extraction of the analyte, and vortex prevents the formation of a biphasic system.
In this study an USVADLLME method was developed for the extraction of the parabens from personal care products in terms of the type and the volume of the extracting solvent (acetone, n-octanol) and the dispersing solvent (methanol, acetonitrile), the ultrasonication and vortex times. Also sodium chloride (NaCl) was used for the salting out effect and the amount of NaCl added was optimized. The analysis of the extracted parabens were evaluated by an HPLC-FD method developed and validated considering linearity, accuracy, precision, LOD and LOQ.
This study is part of the valuation of aromatic and medicinal plants of the spontaneous plant flora that grows in Algeria. This is summarized by the characterization and chemical composition of the volatile part and extracts of Artemisia herba alba from two regions of Algeria: Boussaâda and Ain-Ouassara.
The analytical study of the two essential oils extracted by hydrodistillation was performed by gas chromatography (GC) and confirmed by gas chromatography coupled to the mass spectrometer (GC / MS). 58 compounds could be identified in these essential oils that can be differentiated by the major compounds they contain. Boussaâda (BO) and Ain ouassara, may be respectively part of the chrysanthenone-camphor-α-thujone chemotypes already defined and camphor-chrysanthenone a new chemotype.
High performance liquid chromatography (HPLC) analysis of the extracts obtained by different solvents reveals that the composition of the extracts does not differ much and shows richness in Polyphenols. The caffeoylquinic acids, in particular the 5-quinoyl (chlorogenic acid) and these derivatives are the main components (qualitatively and quantitatively) of the various extracts and represent about 70% of the total extract. A phytochemical study was carried out in order to reveal the profitability of the Polyphenols contained in the extracts obtained.
The study was completed by the determination of antioxidant activity by the DPPH free radical reduction technique. The results obtained showed that the extracts can act as radical scavengers. The concretes seem to be good scavengers of radicals, while, the essential oil of the plant expresses the weakest inhibiting power.
Oxygen, nitrogen and sulfur heterocyclic compounds have been intensively exploited in various areas of medicinal and agricultural applications due to their structural diversity and bio-relevancies.1 we describe a generalized synthetic route towards a new series of hybrid heterocycles, containing pyran-2-one or chromen-2-one nucleus substituted at position 3 with thiazolyl and bispyrazol-2-yl cores2. These structural building blocks are reported via a catalyst-free one-pot three-component reaction of α-bromoacetylated pyran-2-ones, thiosemicarbazideand the pre-prepared polysubstituted-1-(1H-pyrazol-4-yl)butane-1,3-diones as shown in our adopted synthetic strategy. Therefore, a one-pot three-component reaction was performed through the Hantzsch-thiazole protocol and simultaneous formation of pyrazoles. In this method, an equimolar mixture of 3-(2-bromoacetyl)(DHA 10 or coumarin 14), thiosemicarbazide15 and diketo-phenylpyrazoles (6a-e or 9) is brought to react in refluxing ethanol to form thebispyrazole-thiazole-4-hydroxy-6-methyl-2H-pyran-2-one (15a-d and 16)and bispyrazole-thiazole-2H-chromen-2-one hybrids (17a-d and18).
RESULTS AND DISCUSSION
A new series of some new interesting bipyrazolyl-thiazolyl pyran-2-ones and bipyrazolyl thiazolyl chromen-2-ones, have been efficiently synthesized via a one pot three component condensation of -bromoketone, thiosemicarbazide and 1-(3,5-dimethyl-1-phenyl-1H-pyrazol-4-yl)butane-1,3-dione or 1-(3-(substituted phenethyl)-5-hydroxy-1-phenyl-1H-pyrazol-4-yl) butane-1,3-dione. This efficient technique has the advantages of giving products in good to high yields under mild conditions and in short reaction times3. The structure of target compounds was confirmed on the basis of IR spectroscopy, 1H, 13C, 2D NMR spectroscopic spectra (HSQC, HMBC) and mass spectrometry.
Keywords: PYRAZOLES, THIAZOLES, PYRAN-2-ONES, CHROMEN-2-ONES, THREE-COMPONENT SYNTHESIS, 1D and 2D NMR.
We have developed a facile and efficient one-pot catalyst-free three-component reaction for the synthesis of new heterocyclic hybrids bispyrazolyl-thiazolyl-pyran-2-ones 15a-d and16 and bispyrazolyl-thiazolyl-chromen-2-ones 17a-d and18. All these functionalized heterocyclic hybrids contains up to four different types of heterocyclic ringswere obtained in excellent yields and high purity. The structures and geometry of the compounds were elucidated based on 1D and 2D NMR data analysis
 a) Lee, J. S.; Mar. Drugs 2015, 13, 1581, b) Gupta, P.; Gupta, J. K.; Halve, A. K. Int. J. Pharm. Sci. Res., 2015, 6, 2291.
 Yu-Ying, H.; Kimiyoshi, K.; Hiroyuki, T.; Masayuki, K.; Fung, F. W. Tetrahedron Lett. 2011, 52, 3786.
 A. Saidoun, L. Boukenna, Y. Rachedi, O. Talhi,Y. Laichi, N. Lemouari, M. Trari, K. Bachari, Artur M. S. Silva, synlett, 2018, 29, 1776-1780.
Fatty acid amides are the surfactants generally derived from the condensation of fatty acids and amines. They are considered as nonionic surfactants of considerable interest and economical importance. The surface active properties of fatty acid amides makes them an essential ingredient of several formulations such as lubricants, dispersants, detergents, shampoos, antistatic agents, antimicrobial agents, dye corrosion inhibitors, antifoaming agents, and pulping aids . Fatty acid amides are favored in these applications because of their emollient and lubricating properties, ability to stabilize emulsions, and low reactivity . Various approaches for the synthesis of fatty acid amide synthesis have been cited in literature. One route involves the reaction of fatty acid and ammonia under pressure at elevated temperature .
In this study; synthesis procedure involves reaction of excess diethanol amine with long chain monocarboxylic acid ester in the presence of sodium methoxide under a slight vacuum . The characterization of a surfactant’s carbon distribution was performed by HPLC and FTIR. At the same time, amide content (%), free fatty acid (%), free amine (%), glycerin (%), ester (%) were measured.
1- Schmitt Tm. 2001. Analysis of surfactants. Surfactant Science Series 96:61-63.
2- Johansson I. 2003. Kirk–Othmer Encyclopedia of Chemical Technology.
3- Roe Et, Stutzman Jm, Scanlan Jt, Swern D. 1952. Fatty acid amides. IV. Reaction of fats with ammonia and amines. J Am Oil Chem Soc 29(1):18- 22.
Glyphosate (GLY) is the most popular and widespread agrochemical product in the world. In world agriculture, despite the fact that GLY is a class of herbicides and is a generic, it makes the greatest contribution to the protection of healthy crops.
There are two main methods for the production of GLY: iminodiacetonitrile (IDA) technology and production technology using methyl ether.
The production of GLY developed in the course of technical progress in the conditions of tough market competition, and to date, peaceful coexisting IU and IDA technologists have been formed. IU's technology is preferred. Using ME technology, to obtain finished products by synthesis and hydrolysis, dimethyl phosphite, glycine and paraformaldehyde are used as the main raw materials, with a total production of about 83%.
There are dozens of GLY brands on the market under various names. One of the most famous on the US market active drugs N-phosphoromethyl-glycine "Touchdown", the company "Syngenta", contains 60% salt of GLY of trimesium and GLY of trimethylsulfonium salt, containing from 10 to 29% of wetting agent. In Russia, GLY is known under the trademarks “Roundup”, “Glyfor”, “Tornado” and “Uragan”, and in Ukraine under the brands “Roundup”, “Uragan” and others. In 2017, in the Republic of Kazakhstan, the “CHEM-plus" GLY production. In this regard, analysts were tasked to conduct quality control of the finished products of GLY.
The effectiveness of pesticides in the first place, depends on a strictly defined content of the active substance in 1 liter of the product. To find out if the “recipe” of preparation of each new batch of agrochemistry was accurately maintained at production, chromatographic methods of analysis are used. Samples of finished products are always transferred to the chromatography laboratory. The purpose of this research division is the qualitative and quantitative control of the active substances of pesticides in raw materials, in technological products, as well as the mandatory control of the finished product. The content of GLY active ingredients is determined by high performance liquid chromatography. In this scientific work was carried out on the development of the GLY determination method in the finished products of “Faraon Garant” and “Faraon Gold” of the “CHEM-plus" company. When developing the method for determining GLY, the parameters of HPLC chromatography were optimized: mobile phase, stationary phase, flow rate, injection volume and etc. The determination of glyphosate by the developed by us can be considered as a simple, fast, efficient and sensitive method for routine analysis of this compound in finished product of the pesticide.
The isotope dilution mass spectrometry (IDMS) is one of the most powerful and accurate methods for determination of trace elements concentration. It is also considered as a potentially primary measurement method able to ensure metrological traceability to the International System of Units (SI). There are several advantages of IDMS such as high accuracy of the determination of total element concentration in various matrices because the accuracy of the method is determined by the precision of the ratio measurement, less influence of instrument instabilities such as signal drift or matrix effects, no negative effect on the result caused by possible loss of the isotope-diluted sample once the isotope equilibration between the sample and the spike has been achieved. The wide application of the method is limited by disadvantages like the high cost of isotopic materials (if available), existence of at least two stable isotopes of the analyte able to be measured by mass spectrometer free of spectral interferences and highly qualified analysts.
The Bulgarian Institute of Metrology (BIM), as national metrology institute, is determined to provide its customers with services with high metrological quality. In this respect, BIM enhanced its measurement capabilities by implementation of the isotope dilution mass spectrometry, as a primary method, in its activities on element analysis. The main use of ID MS at BIM is for provision of reference values for proficiency tests/interlaboratory comparisons.
In this presentation, the validation of the ID MS method for trace element determination in water samples is presented. The results of the Cd and Pb determination in river water for the purpose of an interlaboratory comparison realized in the frame of the project 16RPT01 ChemMet-Cap, EMPIR are also included. The ID MS method application for confirmation of reference value of element concentration in table water, test object in proficiency test organised by BIM, is explained.
This work is part of the activities included in the project 16RPT01 ChemMet-Cap funded by the European Metrology Programme for Innovation and Research (EMPIR).
We report the phenolic composition and bioactivity of methanolic and aqueous extracts of Berberis thunbergii DC. leaves. The phytochemical profiling and the quantitation of the main phenolic compounds were performed by high-performance liquid chromatography with diode array and mass spectrometry detections. The most abundant compounds in both extracts were caffeoylquinic acids (chlorogenic acid, particularly), followed by caffeoylglucaric acids and quercetin glycosides. Antioxidant and radical scavenging assays (phosphomolybdenum, DPPH, ABTS, CUPRAC, FRAP, metal chelating activity), as well as enzyme inhibitory assays (acetylcholinesterase, butyrylcholinesterase, tyrosinase, amylase, glucosidase and lipase) were carried out to evaluate the potential bioactivity of Berberis thunbergii. The methanolic extract presented the highest antioxidant and radical scavenging values, in agreement with the higher phenolic content when compared to the aqueous extracts. Regarding enzyme inhibitory potential, the methanolic extract was also more potent than the aqueous one for all extracts, representing a better candidate for further studies concerning the isolation of the most bioactive compounds for pharmaceutical purposes.
Nanoscience and nanotechnology, increasingly present in our day to day, currently represent one of the most important research fields. In analytical chemistry, the use of different nanomaterials is an interesting approach to improve the performance of analytical methods. Graphene quantum dots (GQDs) are carbon-based nanomaterials that share characteristics from both graphene and carbon dots. They display unique characteristics, making them promising nanomaterials in a wide range of research fields. Here we report the use of GQDs, along with silver nanoparticles (Ag NPs), as promising nanomaterials for the development of luminescent probes, obtaining enhancements in sensitivity and selectivity.
Glyphosate (Gly) is the most widely used herbicide at the moment. It presents a broad spectrum of action, hence its use for many different crops. Regulatory agencies have constantly mentioned the low hazard potential to mammals. However, the International Agency for Research on Cancer concluded in 2015 that glyphosate is “probably carcinogenic to humans.” For this reason, it is important to develop reliable analytical methods to study the fate and levels of glyphosate in food samples.
We propose an analytical method based on the use of GQDs and cysteine-capped Ag NPs for the screening of glyphosate in pulses. Gly quenches the luminescence of GQDs-Ag NPs system, achieving excellent selectivity and sensitivity (detection limit of 15 ng mL⁻¹). The method developed has been applied to different types of pulses (peas and lupins), obtaining recoveries close to 100% in all cases. Therefore, the simplicity, selectivity, sensitivity and rapidity of this method make it an interesting alternative to other existing methodologies for the analysis of Gly in agri-food samples.
The main goals of this study were to determine the phenolic composition and antioxidant activity of table olives from Olea europaea L. cv. Cornezuelo, as well as the effect caused by a simulated in vitro digestion to evaluate compounds bioavailability. High-performance liquid chromatography with diode-array and mass spectrometry detection (HPLC-DAD-MSn) was used to evaluate the phytochemical profile, whereas conventional spectrophotometric methods (ABTS·⁺ and DPPH) were used to determine the antioxidant activity. The mineral content was also quantified by inductively coupled plasma - mass spectrometry.
Thirty compounds were identified, mainly polyphenols, quantifying the major compounds by HPLC-DAD. After the simulated digestion, the phenolic content suffered an important decrease - more than 50% - reaching losses of up to 75% for oleuropein and comselogoside isomers. This decrease also resulted in a loss of antioxidant activity, observing significant differences for all parameters. However, the analyzed extracts still retained considerable antioxidant potential.
Chemical warfare agents (CWA), including sulfur mustard (mustard gas – HD), dumped in the Baltic Sea after the World War II, still pose a great threat to the ecosystem, maritime economy and people. For these reasons, it is a very important issue to learn about the mechanisms of HD transformation in the marine environment and to determine the impact of selected environmental parameters on the kinetics of these transformations. This knowledge will allow to assess the ecological risk associated with the mustard gas leakage followed by ammunition corrosion, as a result of the passage of time and aggressive environmental conditions. This work determines the influence of sea water temperature on the kinetics of the hydrolysis and/or oxidation of sulfur mustard. The impact of the microorganisms present in the bottom sediments on these transformations was also examined. On the basis of the obtained results, selected kinetic parameters of the HD decomposition reaction and mustard markers were determined.
Zearalenone (ZEA), a mycotoxin produced by several Fusarium molds, can be found in many cereals and related products. The toxicity of ZEA has been reported for both humans and animals. Therefore, many countries have adopted regulations in foods and feed materials to limit the exposure to this contaminant. In this paper, we propose a multicommutated flow-through optosensor to quantify ZEA in different cereal samples. ZEA was retained and pre-concentrated on C18 silica gel, and the use of the multicommutated flow manifold allowed the automated retention/desorption of the mycotoxin on the solid microbeads by the use of appropriate carrier/eluting solutions, hence increasing selectivity and sensitivity of the system. The native fluorescence of ZEA was recorded on the solid phase at λexc/λem of 265/465 nm/nm. A QuEChERS procedure was used to carry out the extraction of ZEA from different cereal samples (maize, hamster feed and rabbit feed). Recovery studies were performed to assess the accuracy of the method, obtaining recovery yields between 93 and 107 % in all the analyzed samples. HPLC-MS was employed as reference method. The quantitation limit of the proposed method was low enough to fulfill the maximum residue levels established by the Commission of the European Communities, thus demonstrating its potential use for the analysis of ZEA in feedstuffs.
Broccolini is originated from crossing the regular broccoli with Chinese kale. Consequently, it has similar properties to these vegetables, but other very particular characteristics. Its consumption has increased in the last few years and, consequently, there have been some studies related to its quality parameters and the influence of different cooking methods. Nevertheless, its phenolic composition and mineral content have not been investigated in-depth so far. Here we report the phytochemical profile of broccolini before and after boiling, steaming, and griddling cooking treatments. The mineral content and phytochemicals were assessed by inductively coupled plasma-mass spectrometry (ICP-MS) and high performance liquid chromatography-mass spectrometry (HPLC-MS), respectively. The main phenolics (mainly hydroxycinnamic acid derivatives from caffeic, coumaric, ferulic and sinapic acids) were quantified. Three oxylipins, three flavonoid glycosides and the glucosinolate glucobrassicin were also identified. ABTS and DPPH assays were also used as screening methods to assess the antioxidant potential of broccolini. A significant loss of the phenolic compounds and a reduction of the antioxidant activity were observed after the three cooking methods. Clear disadvantages were detected when broccolini was boiled, namely high losses of phenolic acids and derivatives (70%). Steaming and griddling also led to a significant loss of phenolics (50%) from fresh broccolini. The mineral content is reported for the first time, calculating the contribution of broccolini consumption to official daily recommendations.
A novel and simple effervescence assisted-deep eutectic solvent based on dispersive liquid-liquid microextraction method has been developed for preconcentration and determination of lead in textile samples by using flame atomic absorption spectrometry. The effervescent agent is environmentally friendly and only causes an increase in the ionic strength, which does not interfere with the extraction of the analytes. Extraction of Pb (II) was performed by using 8-hydroxy-quinoline (8HQ) as a complexing agent, DES prepared by mixing choline chloride and phenol was used as extracting solvent, a solid effervescent agent was added to assist the dispersion of extraction solvent and tetrahydrofuran (THF) was added to ensure the self-aggregation and full separation of the DES molecules from the aqueous solution. The parameters affecting the extraction efficiency were investigated including the concentration of complexing agent, composition and volume of DES amount of THF, composition and amount of effervescent agent. Performed experiments showed that the best effervesce powder composition was NaH2PO4:Na2CO3 with 1 × 10⁻³:2 × 10⁻³ molar ratio and the amount of effervesce powder was 0.367 g. Finally, proposed method was successfully applied to determination of lead in textile samples.
In this study deep eutectic solvent (DES) was used for liquid-liquid microextraction (LLME) of Cd and Pb ions in hair dyes and henna samples. Extracted Cd and Pb ions concentrations in DES rich phase were determined by using microsample injection to flame atomic absorption spectrometer (FAAS). Generally, DES is a type of solvent composed of a mixture that forms an eutectic with a much lower melting point than either of the individual components. Among most DESs that used, choline chloride (ChCl) is a popular component that is similar to B vitamins, and it is a biodegradable and non-toxic salt. Moreover, DESs have some recognized properties, such as poor conduction, high viscosity, low vapor pressure, and high thermal stability. In this method the DES that selected was composed from choline chloride and phenol at the molar ratio optimized as 1:3. In order to obtain maximum extraction efficiency some parameters i.e, pH value, complexing agent (Dithizone 3x10⁻³ M) amount, DES and THF volume, ultrasonication and centrifuging time, affect extraction efficiency were investigated. After evaluating of some analytical features (such as enhancement factor, RSD, LOQ, LOD) optimized method was applied to different hair dyes and henna samples from different origins products and a good recovery values were obtained.
Neurotransmitters are endogenous chemicals that are necessary for the transmission of nerve impulses, neuronal circuitry, neuronal differentiation, interneuronal communications and neuronal growth. Particularly, dopamine (DA) is one of the inhibitory neurotransmitters that plays an important role in maintaining the functional activities of the central nervous, hormonal, renal and cardiovascular systems (Zhang et al, 2009). Furthermore, a malfunction of DA is severely related to many diseases such as hypertension, parkinsonism and restless leg syndrome. Especially, Parkinson’s disease, which is a long-term degenerative disease of the nervous system, shows symptoms of muscular rigidity, slow and imprecise movements and shivering. Consequently, the concentration of DA in urine or blood serves as a substantial indicator about this disease (Karikalan et al, 2016). Several methods such as liquid chromatography, capillary electrophoresis, chemiluminescence and fluorescence have been proposed for the determination of dopamine. Although these techniques provide excellent selectivity in the detection of dopamine as well as some disadvantages, they need long analysis time, high cost equipment, requirement of high quantity sample and sample preparation for determination (Pandikumar et al, 2014). As an alternative to these methods, electrochemical methods are preferable because of their high sensitivity and selectivity, fast response, low cost, easy operation.
In this work, a novel electrochemical sensor was proposed for determination of dopamine which relying on gold nanoparticles modified glassy carbon electrode coated with dopamine memory- poly(carbazole-aniline) copolymer (Cz-co- ANI) film. This sensor electrode was prepared in two steps. Firstly, glassy carbon electrode was coated with carbazole-aniline monomers and dopamine (template molecule) by electrochemical polymerization using cyclic voltammetry. Later, the surface of the dopamine memory-copolymer electrode was coated with gold nanoparticles using cyclic voltammetry and DP memory-GC/P(Cz-co-ANI)-Aunano modified electrode was used as sensor for dopamine determination. Current was recorded against concentration to build the calibration curves that were found to be linear within the range of 10⁻⁵ mol L⁻¹ – 10⁻⁴ mol L⁻¹ for dopamine by using square wave voltammetry. Oxidation potential of dopamine was found at 0.16 V. The linear working graph (at 0.16 V) for dopamine determination: I = 4.24×10⁴ CDP + 1.88 (r = 0.997) were found. Here, I is the current strenght in Amp, and C is mol L⁻¹ concentration. Limit of detection (LOD) for DP were 2×10⁻⁶ mol L⁻¹. Additionally, dopamine determination was made in the presence of ascorbic acid and uric acid. The voltammetric method to be developed was statistically validated against the standard reference method in literature.
In this work, a novel electrochemical sensor using bimetallic nanoparticles of Cu and Au electrodeposited on boron doped diamond (BDD) electrode was developed for the detection of four significant insecticides (dinotefuran, thiamethoxam, clothianidin, and imidacloprid) after separation by ultra-high-performance liquid chromatography (UHPLC). The fabricated nanocomposite modified BDD electrode was investigated for the morphology by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). UHPLC methodology was performed in reverse-phased C18 column with an isocratic condition. The separation was accomplished through a mix of 7% acetonitrile and 0.01 M Britton Robinson buffer (pH 6.4) as a mobile phase. By the differential pulse voltammetry (DPV), CuNPs/AuNPs/BDD electrode enhances anodic peak currents of the insecticides substantially in compare with the bare BDD electrode. Under optimal conditions for amperometry (-1.6 V vs Ag/AgCl), wide linear dynamic range of dinotefuran and thiamethoxam was varied from 0.008 – 1 mM; and clothianidin and imidacloprid was 0.004 – 1 mM with this prepared sensor, respectively. Moreover, an excellent detection limit (3SD/slope) of dinotefuran as low as 0.75 μM was achieved. Finally, this method was successfully applied for the measurement of concentration of insecticide compounds in the honey and vegetable samples with the percent recovered in the range of 97.4% - 101.92%. Thus, this electrochemical sensor based on Cu and Au nanocomposite modified BDD electrode couple with UHPLC can rapidly, selectively, and sensitively detect important insecticides.
Meldonium is a cardioprotective and anti-ischemic drug and it inhibits carnitine synthesis . It has been listed in prohibited substances in sport list in 2016 and since then lots of athletes have been suspended from sport organization due to the use of meldonium. In this study, we synthesized four semi-selective chemosensors with ethidium bromide scaffold (Figure 1 right) which produce response patterns for discrimination of analytes including meldonium. A cross-reactive sensor array using these four chemosensors were constructed on paper microzone plates which is produced by wax printing. Firstly, qualitative ability of the array was tested against a series of molecules and 100% discrimination was achieved using linear discriminant analysis (LDA) (Figure 1 left). Then semi-quantitative analysis was achieved using LDA for different concentrations of meldonium. Finally, artificial neural networks (ANN) was used for meldonium quantitation in spiked urine samples.
This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK) with the project number of 117Z185.
1. S. C. Sweetman, Editor, Martindale: The Complete Drug Reference, Thirty-Sixth Edition; Volume 2, Pharmaceutical Press, 2009.
A colorimetric nanosensor was developed for evaluating peroxyl radical scavenging activity of phenolic antioxidants. Starch was used as a green reduction/stabilization agent for gold nanoparticles (AuNPs) synthesis in alkaline medium. When AAPH (2,2′-azobis(2-methylpropionamidine) dihydrochloride) was incubated with an excess of iodide ions in a 37 °C water bath for 90 min, triodide (I₃⁻) was formed. Upon the addition of starch-stabilized gold nanoparticles (ss-AuNPs) solution to the incubation mixture, triiodide ions were rapidly adsorbed on the surface of AuNPs and caused their aggregation. Aggregation of AuNPs was observed by the reduction of ROO• with iodide, causing a red shift (from 525 nm to 563 nm) of surface plasmon resonance (SPR) absorption and intensified absorbance at the surface plasmon resonance wavelength of nanoparticles, whereas antioxidants decreased this absorbance enabling an indirect estimation of peroxyl radical scavenging antioxidant activity. This AuNPs-based colorimetric sensor is the first of its kind to directly determine peroxyl radical scavenging activity of phenolic antioxidants. The half-maximal inhibitive concentrations (IC50) of selected antioxidant compounds were calculated by utilizing the decrease in absorbance with increasing concentration of scavengers, and compared to those of classical oxygen radical absorbance capacity (ORAC) assay. Epigallocatechingallate (IC50 = 2.4±0.1 μM) was the most effective scavenger among the tested phenolic antioxidants. Green tea and synthetic serum samples were used to test the applicability of the developed nanosensor to real matrices. The results found by the ss-AuNPs sensor were in agreement with those of the ORAC assay. The proposed assay can be used for estimating the peroxyl radical scavenging of various food and biological samples in terms of its low cost, ease of use and compatibility.
The authors express their gratitude to the Research Fund of Istanbul University-Cerrahpaşa for the support given to the project (FOA-2018-30593).
1. S.E. Çelik, B. Bekdeşer, R. Apak, A novel colorimetric sensor for measuring hydroperoxide content and peroxyl radical scavenging activity using starch-stabilized gold nanoparticles, Talanta, 196, 2019, 32-38.
Resveratrol (trans-3,4,5-trihydroxystilbene) is a natural phytoalexin present in many different plants, especially in grapes and has many beneficial effects on health. Scientists have first started investigate the potential beneficial health effects of resveratrol when it first reported its presence in red wine in 1992. In recent years, scientific interest on resveratrol and studies conducted on it have increased with the claim that resveratrol inhibits cancer growth and prolongs survival in cell cultures and animal models.
In this study, a new HPLC-FL method was developed for the analysis of the rabbit plasma samples. In the sample preparation step of the method, precipitation method was used with mobile phase. Quersetin was used as the internal standard. Chromatographic analysis of matters was carried out in C18 column (250 x 4,6 mm, 5 µm i.d.) by isocratic application of acetonitrile-0.2% formic acid (35:65, v/v) mobile phase system at flow rate of 1.0 mL/min. The column temperature was 30 ° C and the drugs was monitored by fluorescence detector at 320 nm excitation and 400 nm emission wavelengths. The validation of the developed method was performed according to ICH rules. The calibration curve showed a linearity of 10-800 ng/mL and LOD and LOQ values were determined as 2,17 ng/mL and 7,25 ng/mL, respectively. The method developed is a fast, accurate and high precision method and will be used in our studies on increasing bioavailability of resveratrol in rabbits.
The Paposo Valley is an special place in Chile located in the cost of the Atacama Desert. Due to the biological diversity of this special área in the most arid Desert in the world, many endemic species of phytochemical interest grow, an example is the species Gypothamnium pinifolium, a plant producing rare phenolic compounds including 2-nor-1,2-secolicoserone (1), one-5-methyl-coumarin: aphilodenticulide (2), and one labdane: ent-labda-8,13-E-dien-15-ol (3). The phenolic compounds of this plant were isolated by chromatography and several derivatives of the mayor compounds were prepared to test in antioxidant and inhibitory enzymes assays. In addition, an HPLC-MS fingerprint was generated and a complete metabolomic profile was performed for this endemic plant for the first time.
Enantioselective chromatography has become a favorite both at the analytical and preparative scales. HPLC and SFC are dominating the scene and are often seen as complementary techniques. While enantioselective HPLC has been preferred method for these tasks, SFC is now taking the lead. This is due to many benefits associated with the use of pressurized carbon dioxide as the major component of the mobile phase. First, CO2 has a much lower cost than the organic solvents used in the normal-phase HPLC mobile phases (hexane or heptane). Aside solvent costs, solvent disposal costs have also impact on the overall economy. Last but not least, health and safety issues are lessened when CO2 replaces with toxic hexane or heptane, the major solvents used in normal-phase enantioselective HPLC.
With this research, we aimed to compare fully porous (FP) and superficially porous (SP) silica particles in SFC from the viewpoint of retention and separation behaviors. For this reason, several chiral columns which have been coated by different amount of cellulose tris(4-chloro-3-methylpenylcarbamate) as chiral selector were tested. On the other hand, a broad range of mobile phase compositions, ranging from 5 to 90% methanol in carbon dioxide, were investigated. While chlorinated polysaccharide CSP have proven to be promising for the separation of chiral sulfoxide species in the past, we were interested in examining the SFC retention and separation in more detail by using some chiral sulfoxide compounds. As a result, resolution always decreased when increasing methanol percentage in all tested columns and the particle types. A practical conclusion issuing from these experiments is that carbon dioxide offers the possibility to enhance retention for those analytes that would be too weakly retained in the polar organic mode.
Bisphenols and phthalates are widely used in the manufacture of numerous household products. Human exposure to these chemicals causes endocrine-disrupting potencies. Therefore, the aim of this work is to develop an efficient extraction method based on a back-extraction step for determination of bisphenol A (BPA), bisphenol S (BPS), monomethyl phthalate (MMP) and monoisobutyl phthalate (MiBP) in meconium for the purpose of detecting prenatal exposure to these substances.
For this reason, samples were analyzed by gas chromatography-mass spectrometry (GC-MS). Hydroquinone was used as internal standard (IS). For quantitation, the MS was run in selected ion monitor (SIM) mode. The ions m/z 207, 357 and 372 (BPA), m/z 182, 379 and 394 (BPS), m/z 89, 163 and 237 (MMP), m/z 221, 149 and 223 (MiBP), and m/z 112, 239 and 254 (hydroquinone) were used as quantifier and qualifier ions. Sample preparation involved sample homogenization of meconium with H2O (1:4 dilution) and then followed by liquid- liquid extraction with 4 mL of tert.-butylmethyl ether (MTBE) at acidic pH (1.0 M HCl). For reduction of matrix effect, the analytes were back-extracted from MTBE layer by 0.5 mL of NaOH (0.2 M) and then re-extracted again by 2 mL of MTBE at acidic pH. The analytes were derivatized with BSTFA w/1% TMCS prior to GC-MS analysis.
As a result, extraction recovery was varied for all analytes between 76.4 % and 95.4%. The limits of quantifications (LOQs) were within 5-10 ng/mL for all substances. The calibration curves were linear in the defined concentration ranges for all compounds. The precision and accuracy of the method were within the acceptable limits. Finally, the method has enough sensitivity and successfully applied to real meconium specimens.
INTRODUCTION: In food sciences, the auto fluorescence of intact food systems in combination with multivariate data analysis has huge potential for food traceability in the context of calibration, as three-way fluorescence data have significant advantages with regard to selectivity and sensitivity, as well as for characterization and classification issues. Regarding the use of three-way data for classification studies, recent reports have been focused on the development of analytical methodologies for food authentication and traceability .
OBJECTIVES: The applicability of front-face excitation-emission fluorescence spectroscopy to compare grape water extracts of two consecutive sampling dates, corresponding with two maturation stages, and subjected to full irrigation and non-irrigation.
RESULTS: The decomposition of the obtained three way grape samples was initially analyzed by means of parallel factor analysis (PARAFAC). A tentative identification of fluorophores was done by matching PARAFAC score values with HPLC measurements. It was found that the first PARAFAC component was highly correlated with the sum of concentrations of catechin and epicatechin. This study demonstrated the potential application of front-face excitation-emission fluorescence matrix, in combination with multiway methods, for the characterization and classification of grapes with different agronomic practices. Data of different order, three- and four-way data, were combined with linear discriminant analysis, (LDA)-PARAFAC and unfolded-partial lest squares (DU-PLS), algorithms. The score values obtained from three-way data PARAFAC decomposition were used in LDA, allowing the discrimination between maturation stages. Similar results were obtained with DU-PLS.
However, the EEMs obtained from grapes with different hydric status were very similar and, for the classification of these samples, it was necessary to add an extra mode. It was demonstrated that the addition of an extra mode, such as a second solvent, to the three-way EEMs data and, in consequence, the use of four-way data arrays, allowed to extract more information from complex samples. This becomes clear in the loading profiles obtained, which present better definition and less overlapping in their excitation and emission maxima. The solvent profiles yielded the fourth dimension to the data and, in consequence, an increase in sensitivity and selectivity was obtained, allowing the classification of the grapes according with its hydric status (Figure 1).
CONCLUSIONS: The results obtained indicated that the use of three-way and four-way data was a good approach for the discrimination between samples with very similar fluorescence profiles. Finally, we want to note that, as far as we know, the use of four-way data arrays for classification issues is reported for the first time.
 S.M. Azcarate, A. de Araújo Gomes, A. Muñoz de la Peña, H.C. Goicoechea, Modeling second-order data for classification issues: Data characteristics, algorithms, processing procedures and applications, TrAC - Trends Anal. Chem. 107 (2018) 151–168
ACKNOWLEDGEMENTS: MCIyU of Spain (Project CTQ2017-82496-P) and Junta de Extremadura (GR180541-Research Group FQM003, and Project IB16058), both co-financed by the Fondo Social Europeo funds, for financially supporting this work.
Nowadays, the requirements for the quality control in pharmaceutical industry are expanding rapidly. This is why new fast and cheap analytical methods for determination of the enantiomeric composition of chiral analyts are needed. Recently, chemometric-assisted spectrometric methods show new possibilities in the field of chiral analysis. The simplicity and the short time of the analysis of these methods are evident advantages in comparison with routinely used chiral techniques.
The aim of this study is to show the feasibility of enantiomeric composition determination of fluoxetine and panthenol in different matrices.
The chiral recognition of enantiomers mixture of the studied drugs was based on the creating the diastereomeric complexes with β-cyclodextrin (β- CD). Small spectral diversities and fluctuations in data originated from various intensity between inclusion complexes, which were formed by enantiomers and β- CD, are possible to describe by multivariate calibration models.
For determination of enantiomeric constituents of fluoxetine in tablets three fluorescence techniques, including excitation, emission and synchronous, were compared to obtain the best recognition of the fluoxetine enantiomers in pharmaceutical samples. All types of measured spectral data were evaluated with multivariate calibration methods (MVC), namely principal component regression (PCR) and partial least square regression (PLS). Obtained MVC results for tablets of fluoxetine were compared with those from chiral HPLC and no significant differences were shown by Fisher (F) test and Student’s t-test. The smallest residuals between reference or nominal values and predicted values were achieved by MVC of synchronous fluorescence spectral data. This conclusion is supported by calculated values of the figure of merit.
An enantiomeric excess (EE) of panthenol in tablets and eye drops was assigned from NIR and UV-VIS spectral data. The PCR and PLS models were constructed from full NIR spectra and three selected wavenumber ranges and for UV-VIS only visible part of spectral range was used. The RMS%RE value of each model was calculated and used for the selection of the spectral NIR region where the best prediction of EE was found. Comparing results obtained from PCR and PLS calibration models, predictive power of PLS models were in better agreement for both spectral techniques.
The characteristics of multivariate calibration models, especially PLS method, proved good prediction abilities of enantiomeric composition of drugs for pharmaceutical preparations in different matrices determined by chemometric-assisted spectrometric methods.
Acknowledgements: This work was supported by the Slovak Research and Development Agency under the contract No. APVV-15-0455. P.M. and R.P. are grateful to the HPC center at the STU in Bratislava, which is a part of the Slovak Infrastructure of High Performance Computing (SIVVP project, ITMS code 26230120002, funded by the European region development funds, ERDF), for the computational time and resources made available.
Flavonoids are a group of naturally compounds widely distributed in the plant. Today, flavonoids have become an important subject for medical research. They possess a remarkable array of biological properties including: anti-oxidative, anti-inflammatory, anti-diabetic and anti-cancer effects. In vitro studies have indicated considerable differences in the anti-oxidative potential, bioavailability, distribution, and metabolism of different flavonoid subgroups, depending on their chemical structures.
In this work, we studied the homolytic and heterolytic antioxidant mechanisms that allow some flavonoïds to eliminate the DPPH radical . The most mechanism thermodynamically favorable is determined using methods proposed in literature. To obtain further information on the investigated compounds, some reactivity descriptors were calculated. All simulations have been performed with density functional theory (DFT), at the B3LYP/6-31G** level.
Understanding the chemical properties and mechanisms generating the antioxidant activity of the studied compounds, appears essential to create new chemotherapeutic agents with improved antioxidant profile.
Over the last years, several analytical applications based on multiway calibration have been developed aiming to improve the performance of the methodologies by exploiting the benefits offered by the higher-order data modeling. In this regard, it is noticeable that third- and fourth-order data-based analytical methods are still scarce despite all the aids that have been already demonstrated . For instance, a) the possibility of decomposing a unique data array for each sample; b) the enhancement of the analytical figures of merit and c) the possibility to tackle collinearity problems arisen from the introduction of an extra mode, are included among the benefits that have been proved and represent the so-called “third-order advantage”. This topic has been a matter of debate among the scientific community and has promoted intensive research towards unravelling its existence and true nature.
In this work, different applications focused on third-order excitation-emission fluorescence matrices (EEM)-based data are described. Instrumental configurations, data generation and data modeling are depicted.
First, a chromatographic procedure coupled to on-line EEM acquisition was developed for the analysis of emergent contaminant in aqueous environmental samples. With this approach, it was possible to acquire 25 sequential EEM for a given chromatographic run. Neither chromatographic flow stop nor fraction collection after chromatographic procedure were required. However, to the best of our knowledge, there is no chemometric algorithm capable to model this kind of data by virtue of the strong dependence between instrumental modes. Thus, an algorithm based on Tucker 3 decomposition is proposed as alternative to model non-trilinear/quadrilinear 4-way data.
In order to provide evidences of the real existence of the third-order advantage, a system consisting on the determination of 3 analytes with identical fluorescence spectra by means of the photodegradation kinetics was developed. For this purpose, the photodegradation of the analytes was monitored by EEM in different UV-irradiation periods of time. Then, the three possible second-order calibration models were compared against the third-order calibration model in terms of predictive capability, figures of merit and retrieved spectral profile evaluation.
Last, study of the evolution of a cell culture registering EEMs. A sterile sample from standard etanercept (Et) process was acquired daily for viable cells count and determination of Et concentration in supernatant by standard off-line univariate techniques. EEM were simultaneously obtained (second-order data) and then arranged in a third-order structure. The later was alternatively modeled by different chemometric algorithms. Firstly, unsupervised decomposition methods Parallel Factor Analysis (PARAFAC) and Multivariate Curve Resolution (MCR) were considered to qualitatively analyse the spectral information. PARAFAC components were putatively related to biological fluorophores present in the culture media during fermentation of CHO cells (aromatic aminoacids, pyridoxine, flavin, folic acid and NAD) demonstrating that a proper modeling of a three-way array corresponding to a single fermentation process, allows extracting extremely useful information about it.
 G.M. Escandar, H.C. Goicoechea, A. Muñoz de la Peña, A.C. Olivieri, Second- and higher-order data generation and calibration: A tutorial. Anal. Chim. Acta 806 (2014) 8– 26.
Hierarchical model builder based on the combination of two chemometric methods, namely principal component analysis PCA and discriminant analysis PLSDA, was applied to UV visible spectral data to classify 36 samples of cinnamon, coriander, cumin and black pepper sold at the local market. The infusion of these spices was made with bi-distilled water during 15 min at 90 °C. The UV spectra of cinnamon extracts were very different from those of other spices. The principal component analysis was applied to the 220-400 nm spectral region with a step of 0.5 nm. Cross-validation was used and allowed to obtain a model with 4 latent variables. The PCA model was used to reduce data (from 361 to 4 variables). The projection of the samples on the plan of the first two latent variables was done to check if it was possible to classify the samples of the four spices. The cinnamon samples were grouped together and separated from the others, the black pepper samples were it to a least degree but the coriander and cumin samples were very close. This PCA model was not able to simultaneously separate the samples of these four spices. The classification of these samples was too complex to be treated with only one model, we used a mixed hierarchical model consisting of Principal Component Analysis PCA and discriminant analysis PLSDA. The results obtained showed that 100% of the samples were correctly classified.
Three advanced, accurate and precise chemometric methods were developed as impurity profiling methods for the binary mixture of bisoprolol (BIS) and perindopril (PER). The two drugs were subjected to acidic and alkaline hydrolysis and the degradation products were isolated and their structures were confirmed via mass and IR spectra. The degradation products were either a drug impurity in British Pharmacopeia or a precursor to such impurity. The methods applied were Partial Least Squares (PLS-1), Alternating Least Squares (ALS) and Artificial Neural Networks (ANN). Genetic Algorithm (GA) was used as variable selection tool to select the most significant wavelengths for the three chemometric models. For proper analysis, a 5-factor 5-level experimental design was used to establish a calibration set of 25 mixtures containing different ratios of the drugs and their degradation products (impurities). The validity of the proposed methods was assessed using an independent validation set. The designed models were able to predict the concentrations of the drugs and the degradation products (impurities) in the validation set and pharmaceutical formulation. The proposed methods presented a powerful alternative to traditional and expensive chromatographic methods as impurity profiling tool.
Powdery mildew of the grapevine (Erysiphe necator) is one of the most prevalent vineyard diseases worldwide. Like other species of the order Erysiphales, it infects the surface of branches, leaves and fruits of the host plant causing fruit weight reduction, low crop yield and changes in the acidity and sugar percentage of the fruit.
Customarily, sulphur based and systemic fungicides are applied to vineyards as a preventive measure, and their application schedule relies on visual assessment of the first symptoms of infection. Early detection of the fungus could allow farmers to start preventive management at the asymptomatic phase of disease, cutting expenses and reducing the use of environmentally harmful fungicides.
In this study, two complementary vibrational spectroscopy techniques (FT-IR microscopy and Vis-NIR spectroscopy) were used to detect and monitor the development of powdery mildew in grapevine. To this effect, three Vitis vinifera cultivars (‘Cabernet Sauvignon’, ‘País’ and ‘Pinot Noir’) from an infected vineyard (Viña de Neira) in Itata valley were regularly sampled from autumn to summer. Dried leaf and grape samples from both sulphur treated and untreated individuals from each cultivar were analyzed under laboratory conditions.
Using principal component analysis (PCA) on Vis-NIR spectra, it was possible to classify samples either by cultivar or by maturity of tissue, showing differences in absorption bands related to chlorophyll content.
Hyperspectral images of infected samples and isolated mycelium were obtained using FT-IR microscopy. The spectra of isolated mycelium showed characteristic bands from lipids, amide I and II, and carbohydrates in the fingerprint region. Using multivariate curve resolution–alternating least squares (MCR-ALS) to resolve the pure spectra of mycelium in each sample image, powdery mildew was identified in some of the samples. In the first two samplings, prior to the application of sulphur treatment, the percentage of infected samples amounted to 47% and 40% of total individuals, respectively. In the following samplings, detection was consistently lower at around 13% of the samples.
Furthermore, hyphae filaments structure and distribution was ascertained, and total infected area was quantified in each image using MCR-ALS, which allowed an estimate of the degree of infection per sample, ranging from 6% to 43 % of affected surface.
Additionally, hyperspectral images of leaf samples infected by other fungal species (Plasmopara viticola and Glocosporium ampelophagum) were acquired. Spectral profiles of the three species were compared. Discrimination between species of fungus was achieved using band ratio index for amide I and amide II.
All in all, spectroscopy techniques are rapid, non-invasive and environmentally friendly tools that might be promissory for the early detection of disease and assessment of the degree of fungal infection.
This work was funded by CORFO/Voucher VIPM18-92600, CONICYT PFCHA/Doctorado Nacional/2018-21181282, FONDECYT Regular/1191281 and Viña de Neira.
The current study was carried out to investigate α-tocopherol, retinol, cholecalciferol and phylloquinone levels as possible in vivo chemoprotective effect of borax (BX) and boric acid (BA) against 3-Methylcholanthrene (3-MC) and Benzo[a]pyrene (B[a]P) induced oxidative damage in rats. The experimental period was performed with 54 male Wistar albino rats. The rats were randomly divided into nine groups of six rats each. Group I: Control, untreated animals were given normal saline (% 0,9 NaCl), Group II: The B[a]P were administered 25 mg/kg via ip. four times. Group III: The 3-MC-treated animals were administered 25 mg/kg via ip. four times, Group IV: BA was given 300 mg/L/day with water. Group V: BX was given 300 mg/L/day with water. Group VI: B[a]P 25 mg/kg via ip four times+BA 300 mg/L/day dosage with water. Group VII: 3-MC 25 mg/kg via ip four times + BA 300 mg/L/day with water. Group VIII: B[a]P 25 mg/kg via ip four times+BX 300 mg/L/day dosage with water. Group IX: 3-MC 25 mg/kg via ip four times+BX 300 mg/L/day with water. The experimental period was continued for 150 days. α-tocopherol, retinol, cholecalciferol and phylloquinone which were determined by HPLC method in rat serum. Statistical analysis showed that the B[a]P group was significantly lower than the control group with regards to α-tocopherol and retinol levels (p<0.001 and p<0.05). On the other hand the 3-MC group was also significantly decreased than control group regarding α-tocopherol and retinol levels (p<0.01 and p<0.05), Similarly, BX group had significantly lower level of α-tocopherol level than control group (p<0.05). However, 3-MC+BX group had significantly lower level of α-tocopherol than control group (p<0.05). Whereas the BA group had increased levels of α-tocopherol and retinol compared to B[a]P group (p<0.01 and p<0.05). The levels α-tocopherol and retinol in the BA group were significantly higher than in the 3-MC group (p<0.05 and p<0.05). Moreover, the B[a]P+BA and B[a]P groups differed significantly in the concentration of α-tocopherol (p<0.05). The difference between the 3-MC+BA and B[a]P group in level of α-tocopherol concentrations were significant elevated (p<0.05). However, level of α-tocopherol, in BX were significantly lower than in the BA group (p<0.05). BA group was significantly higher than the 3-MC+BX group with regards to α-tocopherol (p<0.05). Moreover, no significant differences in cholecalciferol and phylloquinone levels were observed in the all groups, as compared to the control group (p>0.05). it was suggested that administration of boric acid can be used in preventing and treatment of several diseases which may be caused by ROS in rats.
β-lactam antibiotics are the cornerstone of antibacterial treatment and frequently prescribed drugs, especially in the intensive care units (ICU) of hospitals. Contemporary β-lactam antibiotic dosing is debatable in severely ill patients, since the occurrence of pathophysiological changes in critical illness can result in great inter-individual variability. Therapeutic drug monitoring (TDM) is a commonly used dosing strategy to optimize exposure and thereby minimize toxicity and maximize the efficacy. Currently, TDM of β-lactam antibiotics is rarely performed, due to poor availability in clinical practice. We describe here simple and rapid HPLC–MS method for the determination of ampicillin, amoxicillin, cefepime, ceftazidime, imipenem, meropenem, cilastatin and piperacillin in human plasma. This method involves simple sample preparation step and was comprehensively validated according to EMA guidelines . For all analytes, mean accuracy and precision values were within the acceptance value. The lower and upper limits of quantification were found to be sufficient to cover the therapeutic range for all antibiotics. Finally, in collaboration with the North Estonia Medical Centre the feasibility of the analytical procedure was demonstrated in routine clinical practice. This simple, sensitive and rapid assay requires small-volume samples and can easily be implemented in clinical laboratories to promote the TDM of β-lactam antibiotics.
 European Medicines Agency, Guideline on bioanalytical method validation, EMEA/CHMP/EWP/192217/2009 Rev.1 Corr.2** (2015).
The aim of the present study was to examine trace elements, minerals status in postmenopausal patients with osteoporosis and also whether they were correlated with each other in postmenopausal osteoporotic patients.
Study subjects a total of 21 postmenopausal womens with osteoporosis and 23 healthy control subjects were included in the study. Trace element (Cu, Zn, Fe, Co, Mn, Se, Ni, Pb, Cd) and mineral (K, Ca, Mg) levels which were determined by ICP-OES method in human serum.
It has been found out that the osteoporotic patients group was significantly lower than the control group with regards to Cu, Zn, Co, Se, Fe and Mg levels (p<0.05, p<0.001, p<0.001, p<0.01, p<0.01, p<0.01, respectively). In the patients with osteoporotic patients, significantly positive correlations were observed between cobalt and zinc (r=0,572; p=0,007), also, indicates negative significant correlation between the concentrations of selenium and zinc (r=-0,496; p=0.026).
As a result of the analysis, Cu, Zn, Co, Se, Fe and Mg and will be suitable for use as trace element and mineral deficiency in determining of postmenopausal osteoporosis a disease, it is considered to be appropriate.
Acknowledgements: This work was supported by a grant from the Scientific Research Projects Presidency of Van Yuzuncu Yil University (FYL-2017-5540).
Therapeutic drug monitoring ( TDM) defined as the measurement of drug in blood, plasma and serum to individualise treatmant by adopting and determine the dose of drugs to improve clinical activity and efficacy. TDM clearly has the potential to improve the clinical use of drugs.
In this study, two drugs anastrazole and pomalidomide which are clinically important were investigated.
Anastrazole is adrug used to treatbreast cancer who have gone through the menapouse and also whose cancer is estrogen receptor positive. The purpose of monitoring of anastrazole was to define inter individual variation of metabolism and pharmacodynamics.
Plasma anastrozole levels were measured by high-performance liquid chromatography coupled with Tandem Mass Spectrometry (HPLC-MSMS). The blood samples were centrifuged at 4500g for 5 min within the 1 hour following the sampling and stored at -800C until analysis. The plasma samples were extracted by using diethylether:dichloromethane (80:20, v:v) and HPLC-MSMS analyses were performed in Agilent Triple Quadropole Mass Spectrometry system. A reverse phase C18 column (poroshell SB-C18, 2.7 Mikron, 3.0x100mm) was used within the system. The mobile phase was comprised of 5 mM amonium acetate and acetonitrile at a ratio of 15:85 (v:v). Tolteridone was used as an internal standard. The method was linear in the concentration range of 0.5-50 ng/ml (r2: 0.9930). Anastrazole and IS were quantified precursor to product ion transitions of m/z 294.0→225.1 for anastrazol and m/z 326.2→ 197.1 149.0 for IS.
Lenalidomide (LENA) an immunomodulatory drug has significant clinically active in patients with relapsed and multiple myeloma. It is important to determine the most suitable dosage because of its toxicity and therapeutic efficacy.
Agilent 1260 Infinity Liquid Chromatography system and QQQ-6460 dedector was used in this study. Separation was carried out on a Poroshell 120 EC-C18, (4.6 - 50 mm, 2.7µm) column maintained at 30°C. The LC mobile phase consisted of Methanol: 0.1% Formic Acid (90:10% v/v). The flow rate was 0.800 mL/min. The injection volume was 3.0 µL and the runtime was 2.0 minutes. Detection was carried out by a Agilent 6460 triple quadrupole MS/MS fitted with Agilent Jet Stream Electrospray ionization (AJS-ESI) operated in the negative ion mode. Quantification was performed using multiple reaction monitoring (MRM) of the transitions of m/z 258.0 > 213.0 for LENA and m/z 272.0 > 161.0 for Pomalidomide, with the dwell time of 100ms. The calibration curves are consistently accurate and precise over the concentration range of 20 ng/mL to 1000 ng/mL in plasma for LENA.
Two Clinically important drug analysis from plasma were determined and applied to sample for TDM purpose.
1. Bach DM1, Straseski JA, Clarke W.Therapeutic drug monitoring in cancer chemotherapy.
Bioanalysis. 2010 May;2(5):863-79. doi: 10.4155/bio.10.48.
Due to their stepped reactivity in SN reactions, nitro-substituted polyhalogeno-1,3-butadienes have proven to be valuable synthetic precursors for a variety of polyfunctionalized bioactive heterocycles [1,2]. Often times, the building block of choice is 2-nitroperchloro-1,3-butadiene (1) which is easily accessible by the introduction of an activating and directing nitro group into 2H-pentachloro-1,3-butadiene. Synthetic use of 1 opens access to a quite diverse chemistry. The preferred primary reaction center of 1 is the activated terminal carbon atom C-1 of the nitrodichlorovinyl moiety. This carbon atom allows for an attack by different nucleophiles in (SN Vin) processes. Under harsher conditions the internal carbon atom, C-3, is additionally open to the attack of nucleophiles.
In recent years, some N,S-substituted nitrodienes were obtained from the reaction of nitrodienes with thiols, dithiols and also amines. [1,2]
The aim of my study to synthesis and characterization of a new S-; N,S-substituted nitrodienes. All new compounds were characterized on the basis of nuclear magnetic resonance spectroscopy (1H- and 13C-NMR), mass spectrometry (MS), and fourier transform infrared spectroscopy (FT-IR).
 Sayil, C. and Ibis, C. “Synthesis and Crystal Structures of 4,4-Dichloro-2-nitro-1,1,3-tris(phenylsulfanyl)-buta-1,3-diene and 4,4-Dichloro-2-nitro-1,1-bis(phenylsulfanyl)-3-(phenylsulfinyl)-buta-1,3-diene”, Asian Journal of Chemistry, 25(14), 8093-8096 (2013).
 Ibis, C., Sayil, C. and Ozkok, F., “The Reactions of Some Alkyl(thio)substituted 2- Nitrodienes with Piperazines and Structural Study” Z. Naturforsch. 61b, 1174–1179 (2006).
Cancer is a complex disease and usually characterized by rapid and uncontrolled division and proliferation of cells. Cancer causes deaths throughout the world. Lung cancer is a type of cancer that threats the public health. It is the second deadly cause of cancer-related deaths in both men and women. Each year, lung cancer causes approximately 1.5 million deaths globally. Neuron-specific enolase (NSE) is a lung cancer biomarker and found in serum of small cell lung carcinomas (SCLC) patients at high concentration. Additionally, it is a 78 kDa glycolytic enzyme and found in neuronal tissues. Overexpression and enhanced levels of NSE (over than 9 ng/mL) was monitored in 70% of SCLC cases. NSE levels have been measured with enzyme-linked immunosorbent assay (ELISA), which is time-consuming and expensive. Biosensors are rapid, cost-effective and sensitive methods for NSE detection [1, 2].
This study presents a novel approach based on a disposable poly(thiophene)-graft-poly(methacrylamide) modified ITO electrode for the detection of NSE antigen – one of the possible markers of lung cancer. The principle of immunosensor is based on the formation of stable antibody–antigen complexes on modified ITO electrode. Antibodies were immobilized on the ITO electrode surface via glutaraldehyde crosslinking. Electrochemical impedance spectroscopy and cyclic voltammetry were used to monitor the changes on the electrode surface. The proposed immunosensor had a wide linear detection range of 0.02-4 pg/mL and a low detection limit of 6.1 fg/mL. It illustrated good storage stability, excellent reproducibility, selectivity and usability in human serum samples. This technology could be adapted for the detection of other biomarkers in clinical applications.
1,4-Naphthoquinones belong to a family of quinones including benzoquinones and anthraquinone. Quinone is the name given to the dioxo derivatives of the di-hydroaromatic systems. Biologically active 1,4-naphthoquinone ring system is present in various members of the vitamin K group. It is synthesized at industrial scale using catalysts. Various naphthoquinones, particularly those with related side chains, show promise as antibacterial, anti-proliferative and anticancer agents.[1-3]The synthesis of new active derivatives with potential applications in this area and prepared by simple chemical procedures should be of increasing interest.
Here we described the synthesis, characterization and antioxidant activities of 1,4-naphthoquinone derivatives. (Figure 1) Their structures of synthesized compounds were characterized by using micro analysis, Fourier transform (FT)-IR, 1H-NMR, 13C-NMR, MS, ultravioletvisible spectroscopy (UV-Vis).
Cymbopogon citratus, commonly known as lemon grass, mainly used in food and Algerian traditional folk medicine for the treatment of nervous and gastrointestinal disturbances. The aim of the present study is to investigate the antioxidant activities of different extracts (ethanol extract, infusion and decoction) obtained from Algerian lemon grass leaves using different tests such as DPPH (1,1-diphenyl-2-picrylhydrazyl radical) and β-carotene assays. The total phenolic and flavonoid contents were determined using Folin-Ciocalteu and aluminium chloride assays respectively. The quantitative estimation of total polyphenols and flavonoïds showed their existence in all extracts, where ethanol extract of Cymbopogon citratus is the richest in phenolic compounds (4.40 ± 0.52 mg equivalent of gallic acid/g of extract) compared with infusion and decoction (1.32 ± 0.09 and 0.52± 0.03 mg equivalent of gallic acid/g of extract respectively).The evaluation of the antioxidant activity by DPPH showed that the studied extracts have a very good antioxidant activity, especially the ethanol extract of Cymbopogon citratus with an IC50 of 10.6 µg/ml, followed by infusion and decoction extracts with an IC50 value of 13.3 and 15.1 µg/ ml, respectively. In β-carotene bleaching test, the oxidation of β-carotene was effectively inhibited by different extracts of C.citratus, especially the ethanol extract. As a conclusion, the results of the present study indicate that the aerial part extracts of Cymbopogon citratus is a good source of natural antioxidant constituents.
Lycopene is the main carotenoid in tomato. Used a long time like simple food dye, it is today the subject of many studies as for its positive effects on health. To avoid this shortcoming, a useful and green method for the extraction of lycopene with a new procedure using d-limonene (bio-solvent) a substitute for petroleum solvent has been proposed. d-limonene from the orange peel was extracted through a steam distillation procedure followed by a deterpenation process and combining this achievement by using it as a solvent for extracting lycopene from tomato fruit as a substitute of dichloromethane. Lycopene extracted from tomato fruit were compared with both conventional petroleum and bio-solvent in terms of qualitative and quantitative determination. No significant difference was obtained between each extracts allowing us to conclude that the proposed method is effective and valuable. The proposed approach using a green solvent to perform extraction is useful and can be considered as a nice alternative to conventional petroleum solvent where toxicity for both operator and environment is reduced.
One of the principal aims of sustainable and green processing development remains the dissemination and teaching of green chemistry to both developed and developing nations. This paper describes one attempt to show that “north-south” collaborations yield innovative sustainable and green technologies which give major benefits for both nations. In this paper we present early results from a solvent free microwave extraction (SFME) of essential oils using fresh orange peel, a byproduct in the production of orange juice. SFME is performed at atmospheric pressure without added any solvent or water. SFME increases essential oil yield and eliminate wastewater treatment. The procedure is appropriate for the teaching laboratory, and allows the students to learn extraction, chromatographic and spectroscopic analysis skills, and are expose to dramatic visual example of rapid, sustainable and green extraction of essential oil, and are introduced to commercially successful sustainable and green chemical processing with microwave energy.
Phenolic compounds are a large group of phytochemicals that existing in plants as a secondary metabolite and they are synthesized during regular development also as a defense response to situations of stress, such as microbial infections and UV irradiation (Pourcel et al., 2007). Besides these properties, PCs exhibit a wide range of biological and physiological functions, such as anti-allergenic, anti-inflammatory, antimicrobial and antioxidant activities, which are beneficial for human health (Lesschaeve & Noble, 2005). Wine is an important natural antioxidant source within the other alcoholic beverages. Due to complexity of the sample matrix, sample pretreatment techniques before chromatographic detection are used for extraction and preconcentration of analytes from samples. Solid phase microextraction (SPME) technique is based on the establishment of an equilibrium between the analyte and the material coated on fiber support. First, analyte is extracted and preconcentrated on the small amount of sorbent material, then desorbed from the fiber by suitable separation and detected with different technique such as gas chromatography (Dietz, Sanz, & Camara, 2006). Recent advances in SPME are focused on the development and evaluation of novel materials as sorbent coatings that are able to provide high extraction efficiency as well as high selectivity while maintaining high mechanical and chemical stability. In this study, a new coating material modified on stainless steel wire was prepared. For this, [1-(3-aminopropyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide] as ionic liquid (IL) was assembled on graphene oxide (GO) coated stainless steel fiber substrate. Using a new prepared SPME fiber, 12 phenolic compounds in red, white and fruit wine samples were determined by gas chromatography-mass spectrometer after derivatization with trimethylsily derivatization reagents. The characterization of GO-IL material was investigated by FTIR, XRD, TG and SEM. The main experimental parameters influencing extraction and derivatization process were optimized. The analytical parameters were studied (linear range, the coefficient of determination, limit of detection, and repeatability). Also, the extraction efficiency of prepared fiber was compared with commercial SPME fibers (PA, DVB/CAR/PDMS, CAR-PDMS, and CW/PEG). The method was successfully applied to the analysis of PCs in wine samples with good recoveries.
Acknowledgement: This study was supported by a grant from Dokuz Eylul University research foundation (Project no: DEU 2018.KB.FEN.033).
Molybdenum (Mo), vanadium (V) and tungsten (W) are strategic metals with many applications particullary in steel alloys, catalyst in petrochemical, chemical and aerospace industries. Their coexistence in various resources and similar chemical properties makes their extraction and mutual separation very challenging. Speciation of Mo, V and W in aqueous solution (in the form of numerous cationic, anionic and neutral species) strongly depends on their concentration, pH and ionic strength of the mixture. In this work, two aqueous biphasic systems (ABSs), based either on the polymer polyethylene-glycol with molar mass 4000 g/mol (PEG4000) or on copolymer Pluronic PE6200 (PL6200), were evaluated for the extraction and separation of Mo-V-W. Generally, ABS represents one sustainable and controllable approach for the metal extraction between two aqueous phases: upper polymer-rich and bottom salt-rich phases. Determination of the ternary phase diagram of novel PL6200-(NH4)2SO4 ABS at 25°C was performed and demonstrated that PL6200 is considerably more hydrophobic than PEG4000. The partition behavior of Mo, V and W are investigated in ABSs composed of 15 wt% of polymer -10 wt% of (NH4)2SO4 - 75 wt% of H2O, as a function of polymer hydrophobocity. The studied systems have pH ~ 2.8 and ionic strength of 1.06, while the molalities of Mo, V and W were 41, 55, and 30 µM, respectively. The preferentional selectivity for tungsten over molybdenum and vanadium is attributed to the difference in the oxyanion speciation at selected conditions. The speciation of the studied metals, estimated by MINTEQ Visual equilibrium software, indicate that different species are present in the ABS solutions. The lower charge density heptatungstate complex HW7O24-5 is predominant oxyanion form, which has prominent hydrophobic character and contribute to preferential partition of W toward polymer-rich phase. Moreover, increasing the hydrophocity of the polymer significantly improves the extraction of tungsten i.e. distribution coefficient (KW) increases from 10 to 23.6 by replacing PEG4000 with PL6200. On the other hand, low extraction efficiency of vanadium and molybdenum is obtained for PL6200-based ABS, while their partitions are enhanced in more hydrophilic PEG4000 ABS. Higher charged densities species i.e. their decreased hydrophobocity are responsible for reduced distribution in upper-phase of PL6200-(NH4)2SO4-H2O ABS. In sulfate media vanadium exists as VO2+, which can hydrolyzes and form oxy-anions, and VO2SO4- ions while molybdenum is in the form of HMoO4- and neutral aqueous complex MoO3(H2O)3. Improved extraction of the W in PL6200-based ABS under selected conditions results in the high selectivity (S) of W/Mo and W/V separation (SW/Mo = 21.8 and SW/V = 24.1). Therefore, complex polyoxometalate chemistry of studied metals and manipulation of phases’ polarity of polymer based ABS offer flexible strategy for the selective separation of W from V and Mo.
Solid phase microextraction (SPME) as sample pretreatment technique has been preferred in different food samples before chromatographic determination of analytes. SPME, an equilibrium based sample pretreatment technique, provides a single step analysis by integrating sampling, extraction, preconcentration and sample introduction for the target analytes. The main advantages of SPME are fast mass transfer, being solvent-free, simplicity, lower sample volume and high extraction capacity (Arthur & Pawliszyn, 1990). Furthermore, SPME can be used in the analysis of gas, liquid and solid samples and for the determination of volatile, semi-volatile, and non-volatile analytes. So, it is demonstrating great versatility (Spietelun et al., 2013). Phenolic compounds (PCs) and their antioxidant properties have drawn attention because they can be used as a functional food. Antioxidant therapies have been increasingly recognised to be a potential strategy for reducing the risk of cancers, heart diseases and stroke, cardiovascular diseases, and asthma (Kirkham & Rahman, 2006). In addition, application of antioxidants as preservative in food industry is also receiving increasing attention and interests. Thus, developing an optimized and proper method for extraction and quantification of PCs is essential for achieving higher accuracy in results. In this study, extraction and preconcentration of phenolic compounds was accomplished by SPME combined to liquid chromatography with diode array dedection. A 1-(3-aminopropyl)-3-methylimidazolium bromide/tetrafluoroborate (ionic liquid) based montmorillonite (clay) material was prepared and used as SPME coating. The SPME fiber was fabricated with layer by layer onto the surface of stainless steel wire using a dihydroxy ethylene urea crosslinker agent. The applicability and extraction performance of MMT-IL coated SPME fiber was evaluated by detecting twelve PCs in different fruit juice samples using direct immersion-SPME-LC-DAD. Characterization of the structure and thermal properties of coating materials were investigated by FTIR, TG, XRD and SEM. Under the optimized conditions, low limit of detection 2.5 µg/L, good linearity r2> 0.996 and high precision 9.94 % were achieved. The proposed method was successfully applied to analysis of PCs from orange, grapefruit, mandarin, quince, apple, pear and pomegranate fresh juices with good recoveries (> 81.5 %) and satisfactory repeatabilities (RSD < 4.76 %).
Acknowledgement: This study was supported by a grant from Dokuz Eylul University research foundation (Project no: DEU 2018.KB.FEN.033).
Metallic nanoparticles have more superior features, such as optical, catalytic activity, magnetic, electronic, and antibacterial properties, with compared to metal ions. These properties are arisen from their relatively small size and very high surface/volume ratios. Generally, metal nanoparticles are synthesized and stabilized by using traditional procedures, such as chemical and mechanical methods, electrochemical technique, and photochemical reactions. However, these procedures are costly and toxic chemicals are used as reducing and/or capping agents.
In recent years, green chemistry has been gained attention instead of these techniques because hazardous substances are eliminated. The extracts which are bacteria, fungus, virus and plant, are generally used as reducing and stabilizing agents in the green synthesis of metal nanoparticles. Among them, the plant extracts have been widely used because of ecofriendly, simple, rapid, stable and cost effective production of metal nanoparticles when compared other extracts. The water-mediated extraction of plant materials is of great importance in green synthesis method. In general, the metal nanoparticles are obtained by using the whole plant and/or its leaves, roots, flowers or fruits in this synthesis method. It is known that the plant extracts reduce silver ions to metallic silver faster than fungi or bacteria. Therefore, it is mostly preferred for the synthesis of silver nanoparticles.
This study was designed to produce silver nanoparticles using prune extract as reducing and stabilizing agents. Some parameters, such as concentrations of prune and silver salt, time, temperature, affecting shape and size of nanoparticles, were carefully investigated and their optimum values were found. In the synthesis, different concentrations of prune extract (0.5 %; 1.0%; 1.5%; 2.0% and 2.5%) were obtained by boiling under reflux for 5 min. Then, silver solutions were prepared at different concentrations (10-1 M, 10-2 M, 10-3 M, 10-4 M, 10-5 M and 10-6 M) and silver solutions were added onto the extracts and the synthesis of silver nanoparticles were carried out in the dark environment at ambient atmosphere. The synthesized silver nanoparticles under optimum conditions were characterized by UV-Vis, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), fourier transform infrared spectrophotometry (FTIR) and X-ray Diffraction (XRD). Moreover, the antimicrobial activities of the silver nanoparticles were tested on some gram negative and gram positive bacteria.
An ultrasonic assisted hydrofobic DES based liquid–liquid extraction method was used for the separation and preconcenteration of erythrosine prior to its determination Uv-spectrophotometry. Under the optimal conditions, the preconcentration factors obtained 40. The calibration curve was linear in the range of 0.1–10 µg/mL of erythrosine with R 2 = 0.999. Detection limit was 3.75 ng/mL and the RSD was under 3 %. The applicability of the methods was examined by determining erythrosine in pharmaceutical samples. % Recoverys from tablet and syrup that containnig erytrosine were range 94.0-99.0%.
The Lab-In-Syringe (LIS) technique was first proposed in 2012  and represents a synergic link of FLOW-BATCH (FB) automation and SEQUENTIAL INJECTION ANALYSIS (SIA). Today, LIS has demonstrated its potential for the automation of sample preparation protocols, in particular those based on liquid phase microextraction approaches in many applications.
The basic system only requires a computer-controlled syringe pump and a multiposition selection valve, i.e. simple and compact instrumentation, which is available in most laboratories, and integrated in many autosampler systems. In contrast to most flow techniques, its operation is not based on solution stacking and mixing by dispersion, but on the use of the syringe void itself to carry out mixing steps and chemical reactions.
Operational versatility is increased by engaging a magnetic stirring bar inside the syringe to enable homogeneous mixing and liquid phase dispersion , using the syringe upside-down for phase inversion , taking advantage of the transparency of the syringe and its use as a detection cell  or additional inlet via the syringe piston e.g. for drop generation, gas transfer, or semi-continuous sample flow.
LIS has proven efficient and advantageous over other flow techniques in the automation of multiple sample pretreatment procedures including dispersive liquid-liquid microextraction, dispersive solid phase extraction, headspace (singe-drop) extraction, and cloud point extraction [5,6].
This poster presents an overview of the operation principles, potentials, recent applications, and technical developments including 3D printed system elements to enlarge the possibilities of LIS. A closer look on tricks and technical limitations is further given to the newcomers interested in this technique.
Acknowledgements: B. Horstkotte acknowledges the financial support by the Czech Science Foundation by Project No. 301/17/05409S. The work was supported by the project EFSA-CDN (No. CZ.02.1.01/0.0/0.0/16_019/0000841) co-funded by ERDF.
 F. Maya, B. Horstkotte, J.M. Estela, V. Cerdà. Anal. Bioanal. Chem., 404 (2012) 909-917.
 B. Horstkotte, R. Suarez, P. Solich, V. Cerda. Anal. Chim. Acta 788 (2013) 52-60.
 R. Suárez, B. Horstkotte, V. Cerdà, Talanta 130 (2014) 555-560.
 F. Maya, J.M. Estela, V. Cerdà. Anal. Bional. Chem. 402 (2012) 1383-1388.
 F. Maya, B. Horstkotte, J.M. Estela, V. Cerdà. Trends Anal. Chem. 59 (2014) 1-8.
 M. Alexovic, B. Horstkotte, P. Solich, J. Sabo. Trends Anal. Chem. 86 (2017) 39-55.
Surface molecular imprinting is a technology for producing films with imprints of molecules on the surface of carriers. It has a number of advantages in comparison with traditional molecular imprinting (bulk synthesis): an increase in the availability of molecular imprints for target molecules and a sorption capacity, as well as a cheaper sorbent material. Over the past 10 years, many publications have appeared on the use of molecularly imprinted polymers (MIP), including on the surface of the carriers, for the extraction of biologically active compounds by the solid-phase extraction method. In addition, the combination of MIP with electrochemical sensors is being intensively developed for chemical analysis in the field of clinical diagnostics, environmental monitoring and drug screening.
In this work, to obtain molecularly imprinted films on the surface of silica microparticles, an organomineral monolithic polymer was proposed, which was obtained by a “thiol-ene”click reaction between glutathione and 3-methacryloxypropyltrimethoxysilane (γ-MAPS), initiated by azobisisobutyronitrile upon heating, in the presence of quercetin as a template. Samples were obtained in two ways. In the first, the surface of silica microparticles was modified with hydrolyzed γ-MAPS followed by “thiol-ene”click reaction in the presence of quercetin. In the second, an organomineral polymer was obtained in solution using a “thiol-ene”click reaction followed by acid or alkaline hydrolysis of γ-MAPS, and then the product was immobilized on the surface of silica microparticles. Samples obtained in the presence of quercetin, called as molecular imprinted (MIP), and in the absence – non-imprinted (NIP). They were removed template either with a mixture of methanol (ethanol): acetic acid (9:1), or with 0.1 M sodium hydroxide solution.
Re-binding of quercetin was carried out under static conditions from 50 ml of water-ethanol solution. The sorption capacity for all samples varied in the range from 1 to 8 μmol/g. The maximum values were observed for samples obtained by the first way (the ratio of glutathione: quercetin 60:1), however, the imprinting factor in this case was not more than 2.0. While the samples obtained by the first and second ways (the ratio of glutathione: quercetin 6:1) with a small sorption capacity (1-2 μmol/g) showed the maximum values of the imprinting factor (2.0-3.0). The reproducibility of the re-binding was studied using the second way samples by the sorption experiment after each removing template. It was shown that the sorption capacity and imprinting factor for MIP samples obtained by alkaline hydrolysis are reproducible after three consecutive cycles (re-binding - removing template with methanol: acetic acid); and for samples, obtained by acid hydrolysis, the sorption capacity after repeated removing template increases slightly, which leads to an increase in the imprinting factor, calculated after 35 min of re-binding, more than 3 times. Re-binding of quercetin using NIP and MIP samples obeys mainly the pseudo-first-order kinetics.
Thus, the way of obtaining organomineral MIP in solution followed by immobilization on the surface of silica provides more efficient molecular imprinting than the way in which MIP is obtained on the surface of modified silica.
|Technique||Template removal solution||The ratio of glutathione: quercetin||MIP||NIP||IFmax
|Rmax, %||qmax, mol/g||Rmax, %||qmax, mol/g|
|I||0.1 mol/L NaOH||60:1||19.6||5.57||21.0||6.10||2.0 (5)|
|methanol:acetic acid||16.4||8.40||14.7||1.50||1.3 (45)|
|0.1 mol/L NaOH||6:1||16.7||1.52||18.7||1.72||1.2 (25)|
|methanol:acetic acid||22.0||2.03||21.0||1.85||3.0 (55)|
|II, alkaline hydrolysis||0.1 mol/L NaOH||6:1||18.6||1.49||31.7||2.53||2.3 (55)|
|methanol:acetic acid||20.3||1.92||19.5||1.80||1.5 (90)|
|II, acid hydrolysis||0.1 mol/L NaOH||6:1||-||-||-||-||-|
|methanol:acetic acid||10.4||0.92||18.8||1.68||2.1 (35)|
|Number of re-bindings||t, min||Technique II, alkaline hydrolysis||Technique II, acid hydrolysis|
|q, mol/g||IF||q, mol/g||IF|
The oxidation of metallic tantalum was monitored in an oven for X-rays with a graphite resistance under continuous vacuum or under controlled carbon monoxide pressure.
We demonstrate that this brought into play the formation for 2 varieties of Ta2O5 oxide, hemicarbide Ta2C and monocarbide TaC likely to be formed between 293K and 2288K, in accordance with a reaction mechanism which we found to take place over several stages. We determined the crystalline characteristics at high temperatures for all observed solid phases.
Particular importance is attached to the study of thermal expansion of carbides phases.
Curcumin, the main yellow component of turmeric, is a phenolic compound, showing wide ran biological and pharmacological activities. It has high tolerability in the human body but a very low bioavailability that hinders its development as an effective therapeutic agent. In this context, many studies attempted to overcome these limitations by the development of several structural modifications without compromising its beneficial properties. Furthermore, the metal complexes of curcumin and its derivatives are used in several fields of application. As a result, a great deal of research has been devoted to the study of these compounds in order to improve the biological properties of curcumin, as a drug like.
First this work deals to theoretically study and to understand the acetylation of the aromatic moiety in curcumin will alter its activities. Also, we selected Gallium(III) and Indium(III) complexes of curcumin and its diacetyl derivatives, which are taken from the literature, in order to understand the resulting changes in antioxidant activity. The electronic and geometrical structures of these compounds were obtained with employing the density functional theory (DFT). Some of their local reactivity properties and parameters were calculated. In order to gain a better understanding of the antioxidant activity and the impact of the curcumin’s metal complexation and its diacetyl derivative, a comparison of experimental data and theoretical ones of all studied compounds was performed.
Inorganic layered materials, also known as “graphene-like” inorganic analogues, have emerged as a new and versatile source of nanomaterials. Due to their thickness-dependent physical properties they have drawn an enormous scientific interest as regards their exfoliation and the potential use of the exfoliated two-dimensional crystals to attractive new applications in various industrial and technological sectors. This work reports for the first time, the use of low dimensional Bismuthene/Graphene hybrid films as electrode’s modifiers for the ultra-sensitive determination of Pb(II) and Cd(II) ions in the sub microgram-per-liter level by using anodic stripping voltammetry. Bulk Bismuth was exfoliated by a shear-force liquid phase exfoliation method, at 5 oC, in the presence of 5 mg/mL of sodium cholate that plays a dual role as both a solution medium for the exfoliation process and a stabilizer to prevent the restacking of the exfoliated layers.
The effect of the rotation speed on the morphology and electrocatalytic properties of each particular material was investigated with Raman spectroscopy, scanning electron microscopy and various electrochemical techniques.
Compared with bulk Bi/Graphene hybrid film-modified glassy carbon electrodes (GCEs), exfoliated Bismuthene/Graphene hybrid film-modified GCEs exhibited remarkably enhanced detection capabilities and limits of detection at the sub microgram-per-liter level. This work provides for the first time data on the facile preparation of 2D monoelemental bismuthene, which can be easily cast into films offering highly sensitive sensors. In addition, it triggers the development of advanced sensors based on other pnictogens.
In the present work a method was developed for the synthesis of polysiloxane modified with groups of rubeanic acid (DTOAP) using the sol-gel technology. The resulting sorbent was certified by elemental analysis and IR spectroscopy. By elemental analysis the content of carbon, oxygen, nitrogen and sulfur in DTOAP was determined, and the concentration of a surface groups was calculated, it was amounted to 0.92 mmol/g. Since the functional groups of DTOAP contain nitrogen and sulfur atoms, this sorbent was used for the concentration of noble metal ions.
Sorption of silver(I), platinum(IV) and palladium(II) ions was studied under static conditions. The effect of the acidity of the medium on the sorption of metal ions from multicomponent solutions was studied. It was established that DTOAP was quantitatively extracted silver(I) in a wide range of pH; it was mostly extracted platinum(IV) and palladium (II) in an acidic medium compared to the p- and d-metals that were presented in the solution. The sorption capacity of DTOAP for metal ions was calculated from sorption isotherms. It was 0.91, 1.90 and 2.60 mmol/g for platinum(IV), palladium(II) and silver(I) ions, respectively.
The selective properties of DTOAP were also investigated in dynamic mode using concentrating column. It was established that at pH 6.0 the sorbent was selectively removed silver(I) ions, and it was partial separated of platinum(IV) and palladium(II) ions and separated them from accompanying components at pH 3.0. Based on the obtained results a method was developed for selective and quantitative extraction of silver(I) and palladium(II) from multicomponent systems. As well as combined sorption-atomic absorption techniques were proposed for determination of these elements in aqueous solutions using DTOAP. Testing of the developed techniques was carried out on real objects: drinking water, semiconductor paste, elements of radio tubes, activator solutions.
Another area of our research was devoted to the use of DTOAP as an electroactive substance of carbon-paste electrodes (CPE). It was designed several CPE with different content of the sorbent. In the course of the research the parameters and dependencies of the potentials of CPE were determined from various factors: the acidity of the medium, the concentration of metal ions and the content of DTOAP in the composition of the carbon paste. In addition, selectivity coefficients were calculated. It was established that the CPE containing 5 and 10 % DTOAP had the best characteristics. The selected sensors were used as indicator electrodes for the determination of silver(I) and palladium(II) by method of potentiometric titration. The correctness of the proposed methods was tested on solutions of the state standard sample. The concentration of palladium(II) in Pd-600 activator as well as the silver(I) content in the drug «Protargol» were established using these methods.
Thus dithiooxamidated polysiloxane synthesized by the sol-gel method is applicable for the selective concentration of noble metal ions and for their determination by various physico-chemical methods.
The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006.
Montmorillonite (Mt) is a smectite group clay mineral which has wide application areas due to its high adsorption (cation exchange) and plasticity capabilities, advanced liquid absorption and swelling capabilities, colloidal structure and wide surface areas. Mt can absorb toxic materials with surplus liquid in the body. Also, Mt can acts on mucus layer of the body and strengthen the mucosa defences. In the presented study, Sericin was doped with montmorillonite (Mt) with its curative properties were evaluated as anticancer drug delivery.
Silk protein (sericin) is highly preferred in medical applications because of its important properties such as excellent oxygen permeability, cell protective and antioxidant effect, moisture-regulating property, ultraviolet (UV) radiation and protection from microbes, wound healing, anticancer and anticoagulant. In addition, having many different functional groups with ease manipulation makes them a very suitable candidate for surface modification applications.
Herein, drug loaded Mt-Sericin nanocomposites were prepared by desolvation technique and crosslinked by glutaraldehyde. Then, nanocomposites were characterized for their various physicochemical and pharmaceutical properties by using Dynamic light scattering spectroscopy (DLS), Scanning electron microscopy (SEM), Attenuated total reflection-fourier transformed infrared spectroscopy (ATR-FTIR). They also performed to evaluate drug delivery efficiency together with cytotoxic effects on cancer cells. The results of the characterization studies revealed that the synthesis of Mt-Ser composite nanostructures was prepared successfully; homogeneous and uniform nanocomposites were obtained and supported with both morphological and chemical analysis results.
Currently, there is great interest to develop new systems that have the ability to detect or coordinate diverse metal ions, because these analytes are present in aquatic systems (water pollution), as well as active sites of various Metallo-enzymes that regulate different biological processes.¹ Based on this problem, we found to design new compounds that allow sensitive and selective detection and quantification, in addition to studying the electronic changes generated by the coordination of analytes. For this purpose is it possible to use different spectroscopic techniques such as Uv-Vis,² Fluorescence or electrochemical/ electroanalytical techniques.³ On the other hand, the fused ring thiazolo[5,4d]thiazole allow intramolecular electron transfer, it has a rigid structure and also presents coordinate heteroatoms, however, these systems present few studies as chemosensors. Based on this, we propose the synthesis, characterization and determination of Cu²⁺ using ferrocenyl thiazolo[5,4d]thiazoles complexes. The synthesis of 1 – 3 was carried out from two-step cyclization reaction, and were characterized by conventional spectroscopic techniques. Spectroelectrochemistry (SEC-UV-Vis), quantum calculation and different chemical tests indicate a redox reaction (inhibition of PET process) followed by thiazolo[5,4d]thiazole nitrogen protonation (Fig. 1), allowing the determination of nanomolar detection limits by fluorescence spectroscopy and increasing of 32-21-folds the quantum yields of the complexes in presence of Cu²⁺.
The authors thank CONICYT-Chile for Doctoral fellowship, 21150409 (EF); FONDECYT-Chile 1191130 (FG); VRID-USACH for financial support.
(1) Holm, R. H., Kennepohl, P., & Solomon, E. I. Chem. Rev., (1996). 96(7), 2239. (2) Flores, E., Pizarro, J., Godoy, F., Segura, R., Gómez, A., Agurto, N., Sepúlveda, P., Sens. Actuators B Chem., (2017). 251, 433. (3) Godoy, F., Maldonado, T., Flores, E., Agurto, N., Gonzalez, R., Ferraudi, G., Lappin. Appl. Organometal. Chem. (2017). 114 (1814), e4115.
The structure and lattice parameters of the tantalum and tantalum oxides phases were determined by temperature X-ray diffraction under vacuum and low pressure carbon monoxide between 293 and 2278K.
We show that the metallic phase structure is stabilized by inclusion of oxygen into the metal octahedral hole. We determined the crystalline characteristics at high temperatures for Ta and Ta2O5 phases.
Neutral aqueous organic redox flow batteries have many advantages over non-aqueous or strong acidic or alkaline aqueous redox flow batteries due to: 1) less-toxicity, 2) cost-effective, and 3) comparatively high stability during cycling. Among the active species for AORFBs, anthraquinones-2,7-disulfonic acid disodium salt (2,7-AQDS) and potassium iodide (KI) were selected as active materials in KCl solution. The cell voltage of this redox couple is 1.01 V, relatively high value for aqueous redox flow batteries and the redox reactivity and electron transfer rate of both 2,7-AQDS and KI in KCl electrolyte are excellent.
However, there are two problems: 1) low solubility of 2,7-AQDS in KCl solution, and 2) the side reaction of KI. To solve these problems, two additives were used. First, ethyleneglycol (EG) additive was used to increase the solubility of 2,7-AQDS in KCl solution, leading to improve the solubility of 2,7-AQDS in KCl solution from 0.3 M to 0.8 M with EG additive. The mechanism of EG additive effect on increasing the solubility of 2,7-AQDS is based on the hydrogen-bonding and non-polar bonding between additive, active material, and supporting electrolytes (in here, EG, 2,7-AQDS, and KCl, respectively.). Second additive that used in here was polyvinylpyrrolidone (PVP). PVP was used to prevent the side reaction of KI. KI can produce iodine gas or solid through side reaction in aqueous solution. PVP additive acts as a barrier preventing this production of iodine gas or solid by forming povidone-iodine complex. With these two additives, the AORFB using the 2,7-AQDS and KI including EG and PVP additives shows excellent performance (the coulombic and energy efficiencies of 98% and 82%).
Aqueous organic redox flow batteries using carboxylic acid-functionalized alloxazine (Alloxazine-COOH) and potassium ferrocyanide as active materials shows 1.13 V cell voltage and high redox reacitivity and high solubility (~1.97 M in KOH (Alloxazine-COOH)). To further improvement of this AORFB performance, the catalyst (carboxylic acid-functionalized carbon nanotube, CA-CNT) was used to increase the redox reactivity and electron transfer rate. In here, the redox reaction of alloxazine-COOH is the rate-determining step because the electron transfer rate is slower than potassium ferrocyanide. Therefore, CA-CNT catalyst was used for improving the redox reaction of alloxazine-COOH.
The mechanism of CA-CNT catalyst effect on improving the redox reactivity and electron transfer rate of the redox reaction of alloxazine-COOH can be explained with these three main reasons: 1) the role of COOH within alloxazine-COOH as a proton donor, 2) hydrophilic functional groups, and 3) increased number of active sites. The redox reaction of alloxazine-COOH involves the protons on aza-group positions. Therefore, the redox reactivity can be improved with CA-CNT catalyst that acts as proton donors. In addition, measurement of the electron transfer rate constant and diffusivity was performed without and with CA-CNT catalyst to prove the effect of catalyst. With regard to AORFB full cell testing, the performance of AORFB using CA-CNT catalyst was improved (the voltage efficiency was 64% and discharging capacity reaches 26,7 Ah/L, and the state of charge (SOC) attains 83% after cycling.).
Metal-organic frameworks (MOFs) are highly porous materials present many opportunities for applications, such as drug delivery, catalysis, gas storage, chemical sensing, especially biocidal materials . It is well known that Ag-based biocidal materials exhibit antimicrobial properties . Antimicrobial agents are very crucial in medicine, textile industry, water disinfection and food packaging. Nowadays, nanostructured materials as new antimicrobial agents have been well-considered as promising candidates for biomedical applications, on account of their unique chemical, physical, and biological characteristics. Nanoparticles are chemically reactive and can get inside cells, even into the nucleus .
In this study, nano-sized MIL101 supported Ag nanoparticles were prepared and characterized to investigate the biological applications such as antibacterial, antioxidant, DNA cleavage etc. The microstructure and morphology of the MOF-based Ag nanoparticles were characterized by Ultraviolet-visible Spectroscopy (UV-vis), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electron Microscopy (TEM) equipped with an Energy-Dispersive X-ray Spectroscopy (EDX) mapping, X-ray Photoelectron Spectroscopy (XPS) and X-ray Diffraction (XRD) techniques.
Acknowledgement: The authors gratefully acknowledge financial support from the Van Yuzuncu Yil University Scientific Research Foundation
(Project ID: FAP-2019-8244)
In this study, effects of various experimental parameters on the adsorption yield of basic dye in aqueous solution by cyclodextrins biopolymers were investigated statistically in a batch system. The response surface methodology (RSM) based on statistical design of experiments (DOEs) was used in order to obtain the desired response, as an empirical function and to reach easily the optimum of the adsorption yield. A first-order 24 full factorial design (FFD) was planned fixing the adsorption period at 270 min. The experimental design was done at two levels of the operating variables which were the initial dye concentration, pH, agitation rate and NaCl concentration and their studied ranges are 8-16 mg/L, 4.5-7.5, 200-300 rpm, 0.09-0.11M, respectively.
The optimal conditions determined by using surface contour plots for initial dye concentration, pH, agitation rate and NaCl concentration were 12 mg/L, 6, 250 tr/min and 2*10-9 M, respectively. An optimal adsorption yield of about 63.55% was obtained after only an equilibrium time of 270 minutes of experimentation. The interaction between pH and agitation rate on the adsorption yield of the methylene blue was significant, whereas there was no interactions between the other variables.
A simple metal-semiconductor-metal device comprising TiO2 cast from a suspension of Degussa P25 and placed between two metal plates (Al/Al lap shears) demonstrated memristive-like resistive switching behaviour. A mechanism is proposed which relies upon the formation of p and n-type regions within the P25 semiconductor material ultimately leading to the formation of a p-n junction[1,2,3]. This device also exhibited enhanced steady-state currents upon the imposition of potential steps, most notably at higher potential magnitudes (both anodic and cathodic). Indicating a lack of ionic conduction. Sustaining the notion that electrons and holes were charge carriers rather than ions in this simple device.
This research examines the influence of soda-lime-silica glass on the porosity, crystallization and phase transformation of ceramics produced from white corn cob ash. The Corn cobs (CCB) and soda-lime-silica glass (SLSG) are both agricultural and industrial wastes which when sent to landfills constitute environmental challenges. The CCB decays emitting greenhouse gases that cumulate into global warming and the later being non-biodegradable occupies useful land fit for economic purpose. These wastes are however both sources of silica and can be recycled to produce piezoelectric based ceramics materials. The SLSG were crushed and sieved into 45µm grain sizes, while the corn cob was subjected to thermal combustion in open air to yield amorphous silica and then conditioned to 700°C for 6hrs before screening. A mixture of 98, 96, 94, and 92% of CCBA and 2, 4, 6, 8% of SLSG were mixed in a ball mill and then pressed into pellets using polyvinyl alcohol (PVA) as binder and then sintered at 900°C, 1000°C and 1200°C respectively. Microstructure analysis (SEM), XRD, XRF and FTIR analysis were used to analyze the porosity, crystallization behavior, elemental composition and chemical bond formed in the developed ceramics material. The SEM result shows that, as the sintering temperature increases the porosity of the samples decreased. The XRD analysis also reveals a cristobalite dominant phase and small traces of tridymite phases. Fourier transform infrared spectroscope (FTIR) was used to analyze the chemical bond formed in the material.
The new generation drug candidate molecule [Pt(5-Fu)2Cl2H2O] was obtained from the reaction of platinum(II) salt with the anticancer drug 5-fluorouracil (5-Fu). This compound has been characterized by spectroscopic and analytical techniques. Thermal behavior of the compound was also investigated. The electrochemical properties of the compounds have been investigated by cyclic voltammetry (CV) using a glassy carbon electrode. The biological activity of this compound has been evaluated by examining their ability to bind to fish sperm double-strand DNA (FSdsDNA) with UV spectroscopy. UV studies of the interaction of the 5-Fu and metal derivative with FSdsDNA have shown that this compound can bind to FSdsDNA. The binding constants of the compound with FSdsDNA has also been calculated. Thermal decomposition of the compounds leads to the formation of PtO as a final product. In addition, the effect of proliferation 5-Fu and [Pt(5-Fu)2Cl2H2O] were examined on the HeLa cells using real-time cell analyzer with three different concentrations.
Metal oxides are a large class of compounds. They have been studied for a few years for variety of applications because of their electrical and/or magnetic properties extraordinary. Due to their exceptional physical and chemical properties, the rare earth manganites with a general formula RMnO3 are the current options for industrial applications due to their unique characteristics which make them interesting for practical applications. Such materials have potential applications in sensors, magneto-electronics, magnetic data storage, nonvolatile memory, transducers, actuators and gate ferroelectrics in field effect transistors.
There are two types of RMnO3 compounds. RMnO3 manganites wich the rare earth elements with small radii as, Ho, Er, Tm, Yb, Lu and Y, they have a hexagonal structure, whereas the compounds with R = La, Pr, Nd, Sm, Eu, Gd, Tb have a perovskite orthorhombic structure.
The hexagonal YMnO3 has a single axis of spontaneous polarization, and does not contain volatile elements such as Pb and Bi. These properties make YMnO3 a candidate and a major material for applications to nonvolatile ferroelectric random access memories « RAM », magneto-electric sensors, and in the form of layers for the development of the transistors. In addition, it is used in metal-ferroelectric-insulator-semiconductor layered structures for developing the field effect transistors based on ferroelectric effect since it is a single-axis ferroelectric. The yttrium manganite YMnO3 which exhibit a hexagonal structure crystallize in P63cm space group, where each Mn ion is surrounded by three oxygen in plane and two apical oxygen ions forming a MnO5 trigonal bipyramid in crystal structure, has attracted a great deal of interest, especially in recent times, it is considered as a multiferroic material, in which the simultaneous occurrence of the ferroelectric and magnetic orderings exist at low temperature.
On one hand, at room temperature, h-YMnO3 is ferroelectric (FE) with an experimentally reported spontaneous polarization P ~ 5.5 uC/Cm2. At the Curie temperature TC=1273K, it undergoes a ferroelectric phase transition from a ferroelectric (FE) to a paraelectric (PE) phase . At high-temperature, the PE phase is in P63/mmc space group. On the other hand, YMO3 is an antiferromagnetic material. At the Néel temperature TN = 75K, it undergoes a magnetic phase transition from an antiferromagnetic (AFM) to a paramagnetic (PM) phase.
In the non centro-symmetric space group P63cm, h-YMnO3 has six formula units per unit cell, with ahex = 6.1483 Å, and cHex = 11.3993 Å. In 2005, Posadas et al. reported that the YMnO3 films are determined to be relaxed with lattice constants a = 6.13 Å and c = 11.38 Å, these values agree successfully with our obtained results given in the current paper. Our aim in the present paper is to give a wide study on the theoretical investigation of the h-YMnO3 in ferromagnetic state, as structural, electronic, elastic and anisotropic properties using DFT-FP-LAPW-GGA calculations.
|a (A)||c (A)||V (A3)||B0 (GPa)||B'0|
The optical properties of metallic nanoparticles and nanoclusters are remarkably influenced by their interactions with the surrounding environment. Based on this fact, considerable interest has been raised in the development of analytical strategies for the application of metallic nanoparticles and nanoclusters in colorimetric and fluorimetric analysis, respectively. However, optical sensors involving metallic nanomaterials usually involve the use of significant amounts of colloidal solution and their applicability can be compromised by the lack of selectivity and, in certain cases, of sensitivity. In this sense, liquid-phase microextraction (LPME), especially in its headspace mode, is a powerful sample preparation approach that enables excellent preconcentration capabilities, simplicity, sample cleanup and integration of steps. The implementation of metallic nanoparticles and nanoclusters in headspace-based LPME approaches significantly reduces the required amounts of colloidal solution per sample and offers an excellent preconcentration potential. Furthermore, the direct exposure of the colloidal solution to the sample is avoided, thus the in-situ generation conditions can be optimized without the risk of affecting the stability of the colloidal solution (e.g., by aggregation). In addition, potential interferences from non-volatile and semi-volatile matrix components are significantly reduced or even avoided. This work reports on the implementation of metallic nanoparticles and nanoclusters in LPME and their combination with microvolume optical detectors for determination of target analytes. Selected applications involving microvolume UV-vis and fluorospectrometric systems include the determination of halides (iodide and bromide) and mercurials via formation of volatile forms of analytes and exposure of a microdrop of colloidal solutions to the evolved volatiles are discussed. Particularly, colorimetric plasmonic sensing of in situ generated volatiles was carried out using metallic nanoparticles with spherical and rod-like morphologies. In addition, metallic nanoclusters were implemented in LPME systems for the fluorimetric sensing of volatile derivative analytes.
Financial support from the Spanish Ministry of Economy and Competitiveness (Project CTQ2015-68146-P) (MINECO/FEDER) is gratefully acknowledged. F. Pena-Pereira thanks Xunta de Galicia and University of Vigo for financial support. The CACTI facilities (University of Vigo) are also acknowledged.
 C. Bendicho, I. Costas-Mora, V. Romero, I. Lavilla, Nanoparticle-enhanced liquid-phase microextraction, Trends Anal. Chem. 68 (2015) 78–87
 F. Pena-Pereira, I. Lavilla, C. Bendicho, Unmodified gold nanoparticles for in-drop plasmonic-based sensing of iodide, Sens. Actuat. B 242 (2017) 940–948
 F. Pena-Pereira, A. García-Figueroa, I. Lavilla, C. Bendicho, Ratiometric detection of total bromine in E-waste polymers by colloidal gold-based headspace single-drop microextraction and microvolume spectrophotometry, Sens. Actuat. B 261 (2018) 481–488
 M. Martín-Alonso, F. Pena-Pereira, I. Lavilla, C. Bendicho, Gold nanorods for in-drop colorimetric determination of thiomersal after photochemical decomposition, Microchim. Acta 185 (2018) 221
The decentralized analysis of lead in environmental samples would provide the means for the extensive analysis of this contaminants at low cost. For such endeavour, optical methods based on the surface plasmon resonance changes of metallic nanoparticles induced by the presence of the analyte constitute one of the most studied methods.
The rapid room temperature Turkevich method for gold nanoparticle synthesis aided by rhodizonate ion reported recently opens an interesting initial step for the detection and quantification of lead ions in aqueous samples. Rhodizonate anion has long been known as a specific colorimetric agent for lead ions in spot tests, and the presence of this molecule attached to the colored gold nanoparticles would result in a new optical sensor.
Rhodizonate-capped gold nanoparticles were synthezised at room temperature, yielding a surface plasmon resonance band centred at 516 nm, a TEM diameter of 8.7 nm and a DLS diameter of 18.5 nm. After addition of Pb(II) aqueous solutions, the surface plasmon resonance band shifts to higher wavenumbers between 550 and 600 nm, but do not show a defined band at around 750 nm, indicating that no aggregation took place. On the contrary, the observed shift corresponds to the bridging of gold nanoparticles aided by the formation of a complex between adsorbed rhodizonate and Pb(II) ions. A linear range up to 5 mg/L was obtained for the ratio A580/A516. To the naked eye, such spectral changes correspond to a shift between reddish to a violaceous solution.
Competition with other cations showed the interference with Ag(I) ions, which produce a shift of the surface plasmon band but in the opposite direction, turning the solution to orange. Chromium(III) showed a similar behaviour than Pb(II), but dichromate ion did not. The behaviour obtained with Ag(I) ions and Pb(II) ions suggest a different sensing mechanism for both ions, one involving complex formation and the other involving a redox reaction, leading to the formation of core-shell Ag@Au nanoparticles.
N.E. Larm et al., J. Phys. Chem. C 122 (2018) 5105-5118
Free radicals have become the subject of many investigations in recent years, as they have the potential to cause many diseases such as cancer, cardiovascular disease, cataract, immune system reduction, and brain dysfunction. Nowadays, antioxidants that are involved in stabilizing or disabling these free radicals, which cause many tissue damage and diseases, are of great importance (Apak et al., 2016a; Apak et al., 2016b). In recent years, several new analytical approaches have been tried for total antioxidant activity/capacity determination and nanoparticle-based sensors have been used in the determination of antioxidants in general due to their low costs, easy usage, rapid determination of analyte and high precision (Apak et al., 2018). For this reason, a manganese dioxide nanoparticle based spectrophotometric method was developed for the indirect activity measurement of antioxidant compounds. Manganese dioxide nanoparticles can be synthesized easily, quickly and cheaply. The developed method is based on the measurement of the decrease in the color intensity (λmax = 650 nm) of TMB+ cation (nano probe) in the presence of hydrophilic and lipophilic antioxidants. TMB+ cation is obtained via redox reaction between manganese dioxide particles and a chromophore reagent: 3,3’,5,5’-tetramethylbenzydine (TMB) under open air. The linearity, repeatability and recovery parameters that define the reliability and precision of the developed method were tested and the method was validated. The limit of detection (LOD) for ascorbic acid and α-tocopherol in the developed method were found to be 1.6 and 15.6 nM, respectively.
Porous layer open-tubular nano liquid chromatography of enantiomers was performed with an enantioselective open-tubular column. This was the first report in which a preparation procedure for a versatile porous open tubular column was introduced for chiral separations in nano liquid chromatography. The porous layer column was highyl crosslinked and prepared by in-situ polymerization of 3-chloro-2-hydroxypropylmethacrylate and ethylene dimethacrylate in the presence of 1-propanol and dodecanol as a binary porogenic solvent. The reactive chloro groups at the surface of the porous stationary phase were reacted with β-cyclodextrin to obtain an enantioselective chromatographic surface. The various conditions were evaluated to optimize the polymerization and chiral selector immobilization. Scanning electron microscopy, FT-IR spectroscopy were used for the characterization studies, respectively. The results indicated that the cross-linker content (e.g. 23.1 v/v %) on the inner surface porosity of the capillary was very important for final preparation of the porous-layer open-tubular column. The produced open tubular columns contained chiral groups that are very useful chiral separation of the enantiomers. To evaluate the column, the different classes of chiral compounds were investigated. Baseline separation was achieved for the compounds under hydrophilic interaction conditions. The chiral porous open tubular columns showed high enantioselectivity to the related compounds in nano liquid chromatography.
The need for convenient solid-phase extraction (SPE) sorbents has become important in selective extraction and analysis of pesticides from complex matrices. More focus has been turned to carbon aerogels (CAs) because of their highly porous structure, low density and large specific surface area . Due to their thermal and chemical stability and above-mentioned properties, CAs have a great potential for use as sorbents in different sample preparations techniques, such as SPE and SPME (solid-phase microextraction). The CA-based SPE has already been successfully applied for analyzing degradation products of chemical warfare agents .
The current study is focused on the evaluation of CAs suitability as a SPME coating materials for the analysis of selected pesticides from environmental samples. CAs were obtained by pyrolyzing organic aerogels, which were prepared by sol-gel polymerization of 5-methylresorcinol and formaldehyde. Pesticides under investigation are commonly used in agricultural areas and are toxic to different organisms as well as honey bees and humans. The abuse or erroneous application of these pesticides can cause harmful effects on the environment. The applicability of CAs for extraction and preconcentration of selected pesticides was investigated by GC-MS and HPLC-UV.
The CA-based SPME coating material has been successfully synthesized and immobilized on the metal wires and the potential for the efficient and selective extraction of pesticides from complex environmental matrices has been demonstrated. The selectivity of CA-based SPME was much higher than achieved by the commercially available SPME fiber coatings.
 F. Pérez-Caballero. et al., Micropor. Mesopor. Mater 108, (2008) 230–236.
 P. Jõul. et al., Chemosphere 198, (2018) 460–468.
The Estonian Research Council (Institutional Research Fund No. 33-20) and the European Regional Development Fund are acknowledged for financial support.
Pesticides are one of the most serious problems of public health in the world, due to their wide application in agriculture industry to guarantee the crop yield and quality. The detection of pesticide residues plays a significant role in food safety and environmental protection. Reversed phase high-performance liquid chromatography (RP- HPLC) is utilized for the separation of molecules due to their polarity in order to quantify, identify, and/or purify various samples such as those from serum, human and animal tissues, drugs, and foods.
In this study RP- HPLC method was developed and optimized for the determination of chlorothalonil (CLO), dinobuton (DIN) and buprofezin (BUP) in different water samples, tomato and soil samples. Kinetex C18 (150 × 4.6 mm ID × 5 μm) (Phenomenex, USA) analytical column was used stationary phase. Mobile phase which consisted of acetonitrile: 10 mM (pH: 6.54) ammonium acetate buffer solution in the ratio of 75:25 (v/v) at 25 0C with 1 mL min−1 flow rate was determined as optimum conditions.
The optimized conditions were applied for the selective and sensitive determination of CLO, DIN and BUP from well water, tap water, waste water, soil and tomato with the high accuracy values (94.7–106.5%).
Food and environmental safety are a worldwide challenge to human health. Continuous monitoring of food and environmental contaminants through the development of novel and sensitive analytical techniques is a must. Among these contaminants are pesticides which are broadly used by farmers to control crop diseases. These chemicals and their metabolites are usually accumulating in plant tissues and in water which eventually will have negative public health effects on consumers. The detection of these contaminants mainly depends on separation technologies such as liquid or gas chromatography coupled with a mass spectrometer or an immunological interaction such as in enzyme-linked immunosorbent assays. Despite being sensitive and specific, all these techniques require the use of expensive equipment and highly trained personnel which limit their applications in many countries with poor equipped facilities and specialists. To cope with this obstacle, nanomaterials-based biosensors have been proposed as rapid, sensitive, efficient and portable alternatives to the traditional detection techniques. Therefore, in this work we present for the first time a novel electrochemical sensor based on a carbon paste electrode (CPE) modified with bismuth ferrite nanoparticles (BiFeO3/CPE) to detect two of the most commonly used pesticides in agriculture worldwide (imidacloprid “IMD” and fipronil “FIP”). IMD was introduced to the market in 1992 as a first member of the neonicotinoids class (neonics). Neonics and FIP applications in seed and soil represent around 60% of pesticides worldwide. Moreover, IMD usage accounts for 41.5% of the whole neonics market. IMD and FIP were found to be toxic to sensitive aquatic invertebrates at very low concentrations (<100 ng/L). Their chemical properties in addition to their impact on pollinators (honeybees and bumble bees) have raised an EU concern. Therefore, monitoring of both analytes in water is essential to reduce their negative impacts on health and environment. The modified- CPE showed a synergetic effect towards the oxidation of IMD and FIP. The prepared nanoparticles were investigated and characterized using SEM, TEM, XRD and FT-IR. The described voltammetric technique was optimized and validated. Under the optimal conditions, the sensor showed a sensitive response to their determination over a linear range (1 µM – 100 µM) in water. The detection limits (LODs) for IMD and FIP were determined as 0.97 μM and 1.27 μM, respectively. The recovery percentages for IMD and FIP in environmental water samples varied from 90 %-105 %. In conclusion, the developed sensor was successfully optimized and can be used for the simultaneous detection of both IMD and FIP in environmental water samples.
Investigation of propolis samples from different geographic origins of Turkey has embarked as an international collaborative research between institutions of Turkey and Korea. The Turkish institution collects various propolis samples around the Mugla region and tests their biological activities, while the Korean counterpart analyzes their differences by NMR spectroscopy and a statistical method. We are screening propolis samples from various origins to find any difference in the antibiotic activities, and trying to find chemical components responsible for such a difference. We are also to find out a set of metabolites that can be used to differentiate the samples or to predict their efficacy based on the metabolite profiles. Currently, we are still to find proper samples showing antibiotic acitivities, which was not expected because there had been many reports describing such an activity beneficial to human. To understand and explain such a discrepancy, we have also started to investigate the commercially available propolis extracts, as in a liqud and a powder forms, which is advertized over their effecacy and will be used as a reference. The preliminary data show that much larger amount was extracted from the powder form than the liquid. We are currently collecting NMR data for further analysis. This work was supported under the framework of international cooperation program managed by National Research Foundation of Korea (NRF-2018K2A9A1A06065371).
Ceramide, an important component in the metabolism of sphingolipids, plays a significant role in proliferation and apoptosis of cells.1 De novo synthesis of ceramide takes place at the cytosolic surface of the endoplasmic reticulum (ER), and then ceramide is transferred to the Golgi apparatus for conversion into sphingomyelin and glucosphingolipids, mainly by non-vesicular trafficking. Non-vesicular transport of ceramide is carried out by the ceramide transfer protein (CERT) that consists of peptidic motifs and multiple domains.1 The C-terminal (StAR)-related lipid transfer (START) domain is the most important domain, given the fact that it is capable of extracting and accommodating ceramide in its deep hydrophobic cavity. CERT could be an attractive pharmacological target because of its involvement in common pathological processes such as Alzheimer's disease, infectious diseases and cancer.2 A well-known antagonist of CERT is N-(3-hydroxy-1-hydroxymethyl-3-phenylpropyl) dodecanamide (HPA-12);3 however, there is limited structure-activity relationship (SAR) data available.
In this study, we aim to explore the interaction between CERT and HPA-12 and HPA-12 analogs to establish SAR of this compound class by nuclear magnetic resonance spectroscopy (NMR) in order to improve the inhibitory activity of these ligands for a potential drug design.
Herein, we used an optimized expression and purification protocol to prepare an isotopically labeled START domain for getting an idea about the suitability of the protein of interest in receptor-based NMR experiments. The labeled START domain’s monomer in the presence and absence of the ligand yielded promising results in initial 1H-15N HSQC and TROSY NMR spectra. As a next step, sequence specific resonance assignments will be established in order to characterize the binding site and binding mode of HPA-12 and its derivatives.
1. Hanada, K., Kumagai, K., Yasuda, S., Miura, Y., Kawano, M., Fukasawa, M., & Nishijima, M. (2003). Molecular machinery for non-vesicular trafficking of ceramide. Nature, 426(6968), 803.
2. Liu, J., Beckman, B. S., & Foroozesh, M. (2013). A review of ceramide analogs as potential anticancer agents. Future medicinal chemistry, 5(12), 1405-1421.
3. Hanada, K. (2010). Intracellular trafficking of ceramide by ceramide transfer protein. Proceedings of the Japan Academy, Series B, 86(4), 426-437.