Young Scientist Presentations

 


OPY-001

A new SE-HPLC method for simultaneous quantification of proteins and main phenolic compounds from sunflower meal extract

Sara Albe Slabi1, Christelle Mathé1, Xavier Framboisier1, Claire Defaix1, Odile Mesieres1, Olivier Galet2, Romain Kapel1
1Laboratoire Réactions et Génie des Procédés CNRS, Université de Lorraine, Nancy, France
2Groupe Avril, Paris, France

The world population continues to grow and will exceed 9 billion by the end of 2050. Consequently, the global demand for proteins for food is expected to rise at a fast pace in the coming years. Sunflower (Helianthus annuus L.) is the fourth most important oilseed with production reaching the value over 47 million tons in 2016. The solid residue remaining after oil extraction process (sunflower meal) is an attractive source of proteins (30–50 % on dry matter basis, dm) having a high potential for use as a food ingredient [1−3].

Sunflower meal is also rich in phenolic compounds, in particular chlorogenic acids (1–4%/dm, CQAs). Formation of green color covalent complex between CQAs and proteins during protein extraction is the major restriction for their application in food industry [1−3]. The system of extraction and interactions between CQAs and proteins is particularly complex. Its understanding requires a suitable analytical tool able to quantification of both target compounds in aqueous extract.

Although several methodologies have previously been proposed to analyze proteins and polyphenols in liquid samples, each technique had drawbacks, and none allowed a simultaneous quantification. The Kjeldahl analysis used in routine for protein measurement in food are highly fastidious, time-consuming, and harmful for researchers and the environment. In addition, rapid and simple colorimetric techniques (Bradford, Biuret, Lowry, and BCA) can not be used because of signal interferences in complex extract matrix [2]. The first choice for identification and quantification of phenolic compounds from plant material is reversed phase chromatography [4]. However, most of proposed methods were aimed at analyzing polyphenols only. Furthermore, they were developped from meal solvent extracts using methanol or ethanol and consequently contained very few interfering molecules. Thus, the direct and reliable analysis of target compounds in aqueous extract proves to be pafticularly challenging.

The aim of this research was to develop a new method for simultaneous quantification of proteins and main polyphenolic compounds extracted from oleaginous meal by aqueous media. Size exclusion chromatography (SE-HPLC) with a Biosep column (exclusion range 1–300 kDa) and acetonitrile/water/formic acid (10:89.9:0.1 v/v) eluent at 0.6 mL min−1 yielded the most efficient separation of sunflower proteins and CQA monoisomers (3-CQA, 5-CQA, and 4-CQA). The developed method was validated and parameters such as specificity, sensitivity, precision, and accuracy were determined according to current recommendations of International Conference of Harmonization. The results from SE-HPLC correlated well with the concentrations of proteins determined by the reference Kjeldahl method. Additionally, the proposed method was successfully applied for another oleaginous source (rapeseed) making simultaneous analysis of proteins and major rapeseed polyphenols (sinapine and sinapic acid) from aqueous extract possible. Therefore, for the first time the efficient and reliable assay has been developed for quantification of extracted proteins and phenolic compounds in one simple analysis [5]. The proposed chromatographic method offers an advanced and alternative bioanalytical tool useful for better understanding of complex protein/phenol system in liquid phase and optimizing of protein extraction process.



Keywords: size exclusion chromatography, sunflower proteins, phenolic compounds


Fig. 1: SE-HPLC chromatogram of aqueous extract form sunflower meal (pH 9/0 mol L−1 NaCl) using mobile phase consisting of ACN/H20/formic acid (10:89.9:0.1 v/v). UV signal was recorded at 214 nm (bold green line) and 325 nm (thin red line). Internal



Tabl. 1: Parameters of calibration curve, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy determined for sunflower proteins, 3-CQA, 5-CQA and 4-CQA.
ParameterSunflower proteins3-CQA5-CQA4-CQA
Regression slop2 881 41711 936 11711 983 49111 747 434
y interception+5 433 538-32 554-96 483-35 267
Regression coefficient0.9961.0001.0001.000
Linear range (g.L-1)0.82–20.430.01–1.000.05–5.000.01–1.00
LOD (mg.L-1)17.60.70.91.5
LOQ (mg.L-1)58.72.23.05.0
Repeatability (%)RSD≤0.90RSD≤1.05RSD≤2.88RSD≤2.55
Intermediate precision (%)RSD≤4.95RSD≤2.77RSD≤2.84RSD≤3.99
Accuracy (%)100.1±2.1100.6±0.299.4±2.599.6±2.0






OPY-002

Optimization of an in vitro gut microbiome biotransformation platform with chlorogenic acid as model compound: from fecal sample to biotransformation product identification

Olivier Mortelé1, Elias Iturrospe1, Annelies Breynaert2, Eline Verdickt2, Britto Xavier Basil3, Christine Lammens3, Surbhi Malhotra Kumar3, Philippe Jorens4, Luc Pieters2, Alexander L. N. Van Nuijs1, Nina Hermans2
1Toxicological Centre, University of Antwerp, Wilrijk, Belgium
2Natural Products and Food - Research & Analysis (NaTuRA), University of Antwerp, Wilrijk, Belgium
3Laboratory of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Wilrijk, Belgium
4Department of Critical Care Medicine, Antwerp University Hospital, Edegem, Belgium

Until recently, it was believed that the metabolism of xenobiotics occurs mainly by the cytochrome P450 enzyme system in the liver. Recent data clearly show that the gut microbiota play a significant role in the biotransformation of many endogenous molecules and xenobiotics, leading to a potential influence of this microbiotic metabolism on (in)activation and possible toxicity of these compounds. To study the colonic biotransformation of xenobiotics by the gut microbiome, in vitro models are often used as they allow dynamic and multiple sampling overtime. However, the pre-analytical phase should be carefully optimized to enable metabolite identification representative for the in vivo situation.
During this study, chlorogenic acid was used as a model compound to optimize a ready-to-use gut microbiome biotransformation platform using an in vitro gastrointestinal dialysis-model with colon stage together with an instrumental platform using liquid chromatography coupled to high resolution mass spectrometry. Identification of the biotransformation products of chlorogenic acid was performed using complementary suspect and non-targeted screening approaches. Concerning the pre-analytical phase, (i) the influence of different incubation media (Wilkins-Chalgren Anaerobic Broth and phosphate buffer) and incubation times (prior to implementation in the colonic stage of the dialysis model) on bacterial composition and concentration were investigated and (ii) four different sample preparation methods (centrifugation, extraction, sonication and freeze-drying) were evaluated targeting colonic biotransformation of chlorogenic acid.
WCB as incubation medium showed to introduce substantial variation in the bacterial composition of the fecal samples, while the sterile phosphate buffer guaranteed a closer resemblance to the in vivo composition. Furthermore, incubation during 24 h in sterile phosphate buffer as medium showed no large increase or decrease in anaerobic bacterial concentration, concluding that incubation prior to the colonic stage is not needed. Concerning sample preparation, centrifugation, sonication and extraction gave similar results, while freeze-drying appeared to be inferior. The extraction method was selected as an optimal sample preparation method considering the quick execution together with a good instrumental sensitivity. The optimized protocol was applied to chlorogenic acid leading to the identification of 23 microbiotic biotransformation products.
This study optimized a ready-to-use platform to investigate colonic biotransformation of xenobiotics by using chlorogenic acid as a model compound. This platform can be used in the future to study to differences in colonic biotransformation of xenobiotics using fecal samples of different patient groups (e.g. patients with metabolic disorders as fecal donors or fecal samples collected after antibiotic treatment).



Keywords: Gut microbiome, in vitro gastrointestinal dialysis model, liquid chromatography-high resolution mass spectrometry





OPY-003

Headspace solid-phase microextraction using magnetic nanoparticles

Irina Timofeeva, Mariya Alikina, Leonid Moskvin, Andrey Bulatov
Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, RU-198504 Saint Petersburg, Russia

Modern strategies of green analytical chemistry tend towards minimization of reagent consumption and searching for safe solvents and materials for the implementation of sample preparation, which is necessary for the analysis of complex sample matrices. From this point of view, magnetic nanoparticles (MNPs) can be considered as perspective and safe material for sorption. Recently, MNPs have been widely used for separation and preconcentration of diverse compounds from various matrixes (biological samples, foods, environmental samples, etc.). As known, magnetic materials as sorbents have several advantages over conventional sorbents for sorption in aqueous phase. The separation and preconcentration processes can be performed directly in aqueous solution containing MNPs, and after sorption MNPs can easily be collected and separated from the liquid phase using an external magnetic field. Due to the large surface-area-to-volume ratios of nanometer (nm)-sized sorbents, MNPs are particularly useful for extracting and enriching a large volume of different compounds without tedious centrifugation. The compounds absorbed on MNPs can easily be eluted by a suitable eluent for subsequent determination. It should be pointed out, that sorption procedures based on MNPs were only implemented for the separation of the compounds from the liquid phase sample matrixes. In this report, novel phenomenon – gas sorption on magnetic Fe3O4-based nanoparticles held into a gas phase by an external magnetic field will be announced. To the best of our knowledge, this phenomenon discovered has not been presented in literature before. To demonstrate the efficiency of the suggested approach, the proposed strategy was applied for the determination of different volatile analytes in food samples.
_________________________________________________
Authors gratefully acknowledge the Russian Science Foundation (project no. 16-13-10117) for financial support.



Keywords: Sorption, magnetic nanoparticles





OPY-004

Identification and semi-quantification of glycoforms by nano-LC-Orbitrap-MS analysis of intact proteins: application to the α- Subunit of Follicular Stimulating Hormone and Human Chorionic Gonadotropin

Amira Al Matari1, Audrey Combès1, Nathalie Delaunay1, Thierry Fournier2, Valérie Pichon3
1Department of Analytical, Bioanalytical Sciences, and Miniaturization, UMR CBI 8231 CNRS - ESPCI Paris, PSL University, France.
2Laboratory of PhysioPathology and PharmacoToxicology of the Human Placenta, UMR-S 1139 INSERM - University Paris Descartes, Sorbonne Paris Cité, France.
3Sorbonne, Université, France

Glycosylation of proteins is by far the most diverse and complex class of posttranslational modification (PTM). It contributes to health and disease since more than 100 congenital disorders of glycosylation caused by deficiencies in genes involved in glycosylation have been identified. Glycoprotein hormones such as the human chorionic gonadotropin hormone (hCG), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) regulate normal growth, sexual development and reproductive functions. Each glycoprotein hormone consists of two subunits, α and β. They are heterodimers sharing the same α-subunit structure, but each is bound to a unique β-subunit resulting in differences in their physiological roles and signaling. These hormones are considered highly glycosylated proteins due to the presence of several glycosylation sites. The aim of this study is to identify some hCG glycoforms that could be biomarkers of some pregnancy pathologies. In order to characterize hCG glycosylation, a nano-Reversed Phase Liquid Chromatography (RPLC) method coupled to Orbitrap High Resolution Mass Spectrometry (HRMS) was developed for the analysis of hCG glycoforms at the intact level. It allowed the identification of the intact α-subunit isoforms of hCG, but also FSH. The figures of merit of the method were assessed (limits of quantification, linearity and repeatability). Next, it was used for the analysis of 3 batches of a recombinant hCG-based drug (Ovitrelle®) and 3 batches of a recombinant FSH-based drug (Puregon®). The glycoforms of the α-subunit were identified based on their mass in addition to their retention times, since the relative standard deviations of the retention time of each glycoform were calculated and ranged between 0.1-1.9% (n=3) with mass tolerance of 0.03 Da. 42 r-FSHα glycoforms and 44 r-hCGα glycoforms were identified and detected in the three batches. 8 r-hCGα and 7 r-FSHα glycoforms were detected in only one batch but not in all three analyzed batches, which could be explained by slight differences between batches in terms of nature or abundancy of some glycoforms. Only 14 glycoforms were in common between FSHα and hCGα. The batches of each drug were next compared using a semi-quantitative approach based on the area of each glycoform peak observed on its eXtracted Ion Chromatogram (XIC). The area relative standard deviations were calculated and ranged between 0.1-11% for the three batches of FSH and between 0.1-19.3% for the three batches of hCG. This demonstrates the high potential of this method for quality control of pharmaceutical preparations. Furthermore, the sensitivity of the nanoRPLC-HRMS method was next improved by replacing the injection loop of 70 nl by a trapping pre-column allowing the increase of the injection volume up to the µl range. Moreover, a reduction-alkylation step was added before hCG analysis, which allowed the separation in nanoLC of the α- and β-subunits to get also information on hCGβ. In order to determine the hCG glycoforms in placental cell cultures and plasma samples of pregnant women (with or without pathologies), the development of a selective extraction step to concentrate all the hCG glycoforms is now in progress.



Keywords: human Chorionic Gonadotropin (hCG), Follicular Stimulating Hormone (FSH), nanoLC-Orbitrap-MS





OPY-005

Development of an immobilized-trypsin reactor coupled to liquid chromatography and tandem mass spectrometry (LC-MS/MS) for the analysis of long-lived adducts of sulfur mustard with hemoglobin in blood samples

Florine Hallez1, Audrey Combès1, Anne Bossée2, Charlotte Desoubries2, Valérie Pichon3
1Department of Analytical, Bioanalytical Sciences and Miniaturization (LSABM), UMR CBI 8231 CNRS – ESPCI Paris, PSL University, 75005 Paris, France
2DGA CBRN Defence, Analytical Chemistry department, 91710 Vert-le-Petit, France
3Department of Analytical, Bioanalytical Sciences and Miniaturization (LSABM), UMR CBI 8231 CNRS – ESPCI Paris, PSL University / Sorbonne University, 75005 Paris, France

Sulfur mustard is a potent alkylating warfare agent that is highly vesicant and that reacts with blood proteins to form stable hydroxyethylthioethyl (HETE) adducts. Sulfur mustard reacts particularly with hemoglobin (Hb), the main protein present in the red blood cells and composed of four globin chains identical two-by-two (globin α and globin β). The adducts formed with Hb can be used as long-lived biomarkers of exposure to sulfur mustard since they can persist in the organism up to 120 days. Until now, adducts formed with the N-terminal valine residue of both globin chains of the protein are the most studied. Their analysis is based on the modified Edman procedure, that selectively cleaves the N-HETE-Valine adduct from the protein. However, in our laboratory, this time-consuming method has many drawbacks, including poor sensitivity and repeatability. Moreover, the compound obtained after the Edman degradation requires a derivatization step in order to be analyzed by liquid or gas chromatography. Furthermore, alkylation on the N-terminal valine represents only 1-2% of the total adduction induced on hemoglobin upon exposure to sulfur mustard [1]. LC-MS/MS analysis of tryptic digests of Hb showed that alkylation could also occur on six histidine and three glutamic acid residues [2,3].
A new analytical approach was thus developed for the retrospective determination of exposure to sulfur mustard. Targeting all the potential alkylation sites of Hb, this approach is based on the enzymatic digestion of the alkylated protein into peptides, on an immobilized enzyme reactor (IMER) coupled on-line with the LC-MS/MS analysis, thus reducing the handling of the samples. A simplified sample preparation step prior to the enzymatic digestion to extract Hb from whole blood samples enabled the total duration of the method (sample treatment + LC-MS/MS analysis) to be drastically reduced. This new method has yet to be applied for the analysis of blood samples incubated in vitro with sulfur mustard, in order to determine its sensitivity and repeatability in this biological fluid.

[1] D. Noort, R.M. Black, Chem. Weapons Conv. Chem. Anal. Sample Collect. Prep. Anal. Methods, Wiley, Mesilaakso, M., Chichester, West Sussex, England ; Hoboken, NJ, 433–451.
[2] D. Noort, E.R. Verheij, A.G. Hulst, L.P. de Jong, H.P. Benschop, Chem. Res. Toxicol. 9, 781–787.
[3] R.M. Black, J.M. Harrison, R.W. Xenobiotica. 27, 11–32.



Keywords: Immobilized enzyme reactor, hemoglobin adducts, LC-ESI-MS/MS





OPY-006

A Chemometric Approach for Resolving Comprehensive Spectral Interferences in ICP-AES for Complex Matrices. As an Application for REEs Determination in Niobium-Rare-Earth Ores

Andrey M Zybinsky1, Vladimir P Kolotov1, Vasily K Karandashev2
1Laboratory of Substances and Material Determination, Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Moscow, Russia
2Laboratory of Nuclear Physics and Mass Spectrometry Analysis, Institute of Microelectronics Technology and High Purity Materials RAS, Chernogolovka, Russia

It is well-known atomic emission spectroscopy is often complicated by spectral interferences. In spite of the fact that modern atomic emission spectrometers are being equipped with advanced software but quite frequently it does not allow to resolve entirely the interferences problem. In this case analyst should rely on her/his experience to select the best free from overlapping spectral lines. Sometimes there are not free spectral lines from overlapping at all. Especially one of the challenging issues for AES analysis is REE determination due to enormous existed number of overlapping spectral lines. In this work we have developed a new approach for resolving complex spectral interferences.
The Software “eSpectReS” (The Emission Spectra Resolving System) has been developed that optimizes tasks of determining specified elements. The program contains an extensive database of spectral lines, which allows modeling spectra based on priori information about sample composition, taking into account individual characteristics of a spectrometer and showing intensities at specified parameters. Also a method of mathematical resolution of spectral interference has been developed. The method is based on a special spectrometer calibration, the result of which is a linear equation system matrix which consists interference coefficients. The measurement result of analysed samples is determined as the right part of a system of linear equations. One of the futures of this program is that it allows both to propose a set of calibration mixtures, and to resolve spectral interferences using a regularization algorithm with a provision of an estimate of measurement uncertainty. An important aspect of the work is evaluating of the true detection limits with presence of spectral interferences for varying component concentrations at different degrees of overlapping. As an example the determination of REEs in rare-earth ores is presented with results of analyses and their uncertainties. In addition accuracy and precision were examined by analyse of different certified REE reference materials. Using the developed approach to resolve spectral interferences, the technique of direct REEs determination in their ores was attested. This methodology has been successfully applied in a sectoral institute to estimate rare earth elements deposits and their reserves.



Keywords: inductively coupled plasma atomic emission spectrometry, spectral interferences, rare-earth elements.





OPY-007

UHPLC-HRMS/MS method for determination of multi-class cyanotoxins in freshwater

Daria Filatova1, Massimo Picardo1, Oscar Núñez2, Marinella Farré1
1Spanish National Research Council, Institute of Environmental Assessment and Water Research, C. Jordi Girona 18-26, Barcelona, 08034, Spain
2University of Barcelona, Faculty of Chemistry, Department of chemical engineering and analytical chemistry, C. Martí i Franquès 1-11, Barcelona, 08028, Spain

Cyanobacteria are the components of regular microbial succession in periphyton formation. They are spread globally in different aquatic environments. The community distribution is affected by water quality, flow regime, climate, and geology. During the past decades, there has been a noticeable increase in cyanobacterial blooms, dominating in many freshwater bodies worldwide. Under favourable conditions, some species are known to produce toxic secondary metabolites (cyanotoxins), which vary in structure and harmful properties, and being a major concern for drinking water supply and recreational water use. The most described and diverse cyanotoxins are microcystins (MCs). The common structure of MCs is cyclo(D-Ala-L-X-D-erythro methylAsp(iso-linkage)-L-Z-Adda-D- Glu(iso-linkage)-N-methyldehydro-Ala). The structure differ in the the L-amino acid residues 2 (X) and 4 (Z), which are represented by a two-letter suffix. For instance, MC-LR contains leucine (L) in the position 2 and arginine (R) in the position 4. Thus, MC-YR is for tyrosine and arginine, -RR is for two arinines, and -LA, -LF, -LY, -LW are for leucine and alanine, phenylalanine, tyrosine and tryptophan, respectively. The World Health Organization appointed a provisional guideline value for total MC-LR in drinking water of 1 µg/L. To monitor cyanotoxins’ levels and prevent both human poisoning and wildlife damage, suitable analytical methods need to be developed.

This work presents the development and application of a validated sensitive, fast and robust method for the simultaneous determination of 10 cyanotoxins in freshwaters based on ultra-high performance liquid chromatography coupled to high-resolution tandem mass spectrometry (UHPLC-HRMS/MS). For the sample pretreatment, dual solid phase extraction using 2 cartridges has been validated and employed. The chromatographic separation was achieved using a C18 analytical column (150x2.1 mm, 2μm) with acidified acetonitrile and water as a mobile phase. The total chromatographic run was 10 min. The chromatographic separation was coupled to a Q-Exactive Orbitrap instrument (Thermo Fisher Scientific), and the MS data was acquired in both full scan and parallel-reaction monitoring modes (PRM).

This method provides targeted determination of cyanotoxins of different chemical classes (cyclic peptides: MCs, nodularin; a becyclic secondary anatoxin-a and an alkaloid cylindospermopsin) with method limits of detection (MLODs) ranging from 0.02 – 76 pg/L, much lower than the limits established by legislation. To our knowledge, these are the lowest reported MLODs for the determination of multi-class cyanotoxins. Method recoveries were evaluated by analysing artificial freshwater samples in triplicate spiked with 10 cyanotoxins at 3 concentration levels (2, 10, and 20 ng/L). Recoveries at the highest tested level were in the range of 60.5 – 87.3 %, except for MC – LW (35 %). Application of PRM gave an opportunity to identify the most abundant fragments for each toxin. Due to the number of confirmation strategies such as HRMS, HR-MS/MS ions, this method can be proposed for both environmental and food analysis. Additionally, HRMS provides an assessment of the potential presence of transformation products and other non-targeted toxins in the samples. The developed method was applied for the study and characterisation of cyanotoxins concentrations in Catalonia freshwater reservoirs during spring and summer 2018.



Keywords: Cyanotoxins, microcystins, high-resolution tandem mass spectrometry.





OPY-008

Application of a new method for the suspect screening of natural toxins in surface water reservoirs

Massimo Picardo1, Daria Filatova1, Oscar Nuñez2, Marinella Farré1
1Department of Environmental Chemistry, IDAEA-CSIC, 08034 Barcelona, Spain
2Department of Chemical Engineering and Analytical Chemistry, University of Barcelona, 08028 Barcelona, Spain

Natural toxins produced by harmful algal blooms (HAB), mycotoxins and phytotoxins can contaminate the aquatic environment including water reservoires, becoming a potential treath for human health (Gestal Otero, 2003; Morabito, Silvestro, & Faggio, 2018). Global warming and anthropisation are also modifying the frequency and the intensity of the harmful bloom events, which have increased during the last years (Wells et al., 2015).
Due to their toxicity and potential damages to human health, a great effort in the development of analytical methods for the determination of natural toxins in surface water has been carried out during the last decade. However, most of these analytical methods have been designed for target analysis of selected groups of compounds. Considering the climate change and the multiple stressors affecting natural water reservoirs, suspect screening methods able to detect new toxins and their degradation products are highly required.
In this work, a new approach for the suspect screening of a wide range of natural toxins including mycotoxins, phytotoxins and cyanotoxins using the power of the high-resolution mass spectrometry (HRMS) is presented. High-performance liquid chromatography (LC) coupled to HRMS combined with an in-silico approach for the exact mass features data treatment was applied. In order to eliminate polar interferences from surface water samples an extraction ad clean up approach for a wide range of toxins polarities was proposed using solid-phase extraction (SPE) with three different cartridges in series. The performances of the suspect screening were tested using samples spyked with anatoxin-a (Ana), cylindrospermopsin (Cyn), microcystins (MCs), aflatoxin B1 (AflB1) and nodularin (Nod). Method performances showed that the toxins from different groups were recovered between the 73 and 116%.
For the analysis, a method based on LC-HRMS using an Orbitrap Qexactive instrument was applied. The cromatografic separation was in a C18 analytical column using water and methanol as mobile phases both acidified with formic acid. Adquisition was performed in full-scan mode and all ion fragmentation (AIF) in parallel under negative and positive ionization with a MS resolution of 70000 full width at half maximum (measured at m/z 200). Data were processed using the Compound Discoverer version 2.1 v. x86 (Thermo Fisher Scientific, San Jose, CA, USA). For the tentative identification of toxic substances, HRMS and fragmentation spectrum were used comparing the data from the in-house database and the reported data from different open sources databases such as Springer Nature and Chemspyder.
Finally, the method was applied to assess the content of natural toxins in surface water of the “Ter” river (41.969816, 2.393997, Catalonia, NE Spain) near the water catchment area for drinking water production. More than 25 natural toxins were tentatively identified. Microcistin LR (MC-LR), Ana, AflB1, Nod, acetoxytropane, xanthotoxol, coumestan, arecoline and other different compounds were tentatively identified. Microcistin LR (MC-LR), Ana, AflB1, Nod, were also reconfirmed using standards and quantified, showing concentrations in a range between 0.003 and 0.54 μg/L.



Keywords: Natural toxins, Liquid Chromatography-High Resolution Mass Spectrometry, Water.





OPY-009

Utilize 3-mercaptopropionic acid modified HgSe nanomaterials for surface-assisted laser desorption/ionization mass spectrometric analysis of biomolecule and synthetic polymer

Cheng Kang Chiang, Yi Hsuan Chou, Yi Xian Wu
Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 97401, Taiwan, ROC

Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using nanomaterials as matrices has been proven effective in the analysis of different types of analytes. In this study, we elaborate the applicability of various mercapto acids as capping reagents for the preparation of HgSe SALDI nanomaterial matrices for the detection of peptides, proteins, and synthetic polymers. Our data revealed that both the side methyl group and the suitable chain length of mercapto acids play an essential role in controlling the shape and optical properties of HgSe. Among the investigated mercapto acids, 3-mercaptopropionic acid modified HgSe provided excellent SALDI performance, including fewer fragment ions, less interference from alkali-adducted analyte ions, higher analytical sensitivity, and better data reproducibility. Limits of detection in the picomolar and femtomolar ranges were achieved for BSA and artificial peptide. Besides, up-to-10-fold signal enhancement of polystyrene polymer (MW at 2k Da) observed using HgSe as addictive with dithranol matrix.



Keywords: SALDI-MS, Biomolecule





OPY-010

Beverage classification using Linear Discriminant Analysis with covariance matrix shrinkage

Barış Gün Sürmeli1, Imke Weishaupt2, Knut Schwarzer2, Jan Schneider2
1Institute Industrial IT, OWL University of Applied Sciences and Arts
2Institute of Food Technology NRW, OWL University of Applied Sciences and Arts

To accomplish beverage classification task using Neuro-Infrared (NIR) Spectroscopy data, a powerful method, Linear Discriminant Analysis (LDA) enhanced with Leodit-Wolf Covariance Matrix Shrinkage (Shrinkage-LDA) is employed. On three beverage data sets, the performance of Shrinkage-LDA is compared to the conventional chemometrics methods; Principal Component Analysis – Linear Discriminant Analysis (PCA-LDA), Soft independent modelling of class analogies (SIMCA), Partial Least Squares – Discriminant Analysis and Artificial Neural Networks (ANN). Results show that Shrinkage LDA achieves significantly superior and more stable performance which can be implemented in newly developed chemometric tools.



Keywords: Beverage classification, Neuro Infrared Spectroscopy, Shrinkage-LDA





OPY-011

18O labeling ratio of adenosinetriphosphate at different positions by LC-qTOF-MS

Cemil Can Eylem1, Açelya Erikçi2, Samiye Yabanoğlu Çiftçi2, Sedef Kır1, Emirhan Nemutlu1
1Department of Analytical Chemistry, Hacettepe University Faculty of Pharmacy, Ankara, Turkey
2Department of Biochemistry, Hacettepe University Faculty of Pharmacy, Ankara, Turkey

Nucleotides are the building blocks of nucleic acids and have a variety of functions in cell metabolism. They are units of energy in metabolic transformations, cofactors of intermediary basic molecules and a number of enzymes in the response of cells to hormones and other extracellular stimuli, and are also structural components of metabolic intermediates. Structural analysis of nucleotides is important in understanding the role of endogenous nucleotides as well as the development, biochemical analysis and therapeutic use of new nucleotide-based tools. A deeper understanding of the biological effects and methods for studying structures in an increasing number of applications for nucleotides are in high demand and mass spectrometry is the primary tool. Incorporation of ¹⁸O-stable isotopes into oligophosphates reflect turnover rates of different phosphoryl moieties and thus its quantification offers a tool to reveal unique information regarding respective enzyme’s activities. The most important advantage of the ¹⁸O methodology is that it can measure almost every phosphotransfer reaction taking place in the cell, including whole phosphonucleotides turnovers and their metabolically active pool sizes. That’s why, suitable fragments must be selected to determine the percentage of ¹⁸O labeling of phosphates in different regions of the adenosinetriphosphate (ATP). For his purpose, LC-qTOF-MS method was developed for the analysis of phosphates in different positions of ATP (α, β and γ) for use metabolomics and fluxomics analysis using different collision energies in this study (Figure 1). The measurements were performed with an LC–qTOF-MS (Agilent 6530) using Merck ZIC-pHILIC (150 mm x 2.1 mm, 5 μm) column with a 0.17 mL.min⁻¹ flow rate constituted from 20 mM ammonium carbonate (pH 9) containing 5% acetonitrile (mobile phase A) and acetonitrile containing 5% water (mobile phase B) in gradient elution mode. The method has been applied to colon carcinoma cell lines and the labeling ratio of ATP at γ position almost 6 times higher than β position.



Keywords: 18O labelling, fluxomics, LC-qTOF-MS


Spectra of ATP molecules in different collision energies







OPY-012

Generic Extraction Medium: From Highly Polar to Non-polar Simultaneous Determination

Shakiba Zeinali, Habib Bagheri, Mehrdad Khalilzadeh
Chemistry Department, Sharif University of Technology, Tehran, Iran

Sample preparation for non-target analysis is challenging due to the difficulty in the extraction of polar and non-polar analytes simultaneously [1]. Most commercial solid sorbents lack the proper comprehensiveness for extraction of analytes with different physiochemical properties [2,3]. A possible key is the combination of hydrophobic backbone polymer and addition of hydrophilic surface functional groups in solid based extraction methods in order to generate the susceptibility for retaining both polar and non-polar analytes [4]. To pursue this goal, in this study, four polar groups including -NH₂, -NO₂, -COOH, and -COCH₃ were chemically bound to Amberlite XAD-4 substrate in order to prepare a generic extraction platform. To validate the applicability of extractive phases, 22 analytes possessing wide range of polarities (LogP range between −2 and +7) were chosen for extraction using the synthesized polymers by online micro solid phase extraction (μ-SPE) and further analyzed with high-performance liquid chromatography and UV–Vis detection (HPLC-UV). The recovery data were compared with commercial sorbents by t-test, principal component analysis (PCA) and hierarchical cluster analysis (HCA). Amberlite XAD-4 modified with COOH group (XAD-COOH) revealed extraction efficiencies statistically better than commercially available sorbents including LiChrolut® EN, Oasis® HLB and Amberlite® XAD-4®. The reproducibility and repeatability of XAD-COOH were also studied and acceptable results were obtained. Furthermore, the swellability of polymers was also measured and the results were comparable with commercial ones. To evaluate the extraction ability of XAD-COOH in real sample matrix, water sample near a heavy crude oil spill, urine and hospital wastewater were analyzed. Comparison of the data with LiChrolut® EN corroborates the dominance of XAD-COOH for screening analysis.

[1] C. Baduel, J.F. Mueller, H. Tsai, M.J.G. Ramos, Development of sample extraction and clean-up strategies for target and non-target analysis of environmental contaminants in biological matrices, J. Chromatogr. A, 1426 (2015) 33-47.
[2] B.L. Milman, I.K. Zhurkovich, The chemical space for non-target analysis, TrAC, Trends Anal. Chem., 97 (2017) 179-187.
[3] S. Samanipour, J.A. Baz-Lomba, M.J. Reid, E. Ciceri, S. Rowland, P. Nilsson, K.V. Thomas, Assessing sample extraction efficiencies for the analysis of complex unresolved mixtures of organic pollutants: A comprehensive non-target approach, Anal. Chim. Acta, 1025 (2018) 92-98.
[4] P. Fabbri, M. Messori, Surface Modification of Polymers: Chemical, Physical, and Biological Routes, in: Modification of Polymer Properties, Elsevier, 2017, pp. 109-130.



Keywords: Generic extraction, solid phase extraction, non-target analysis





OPY-013

New applications deep eutectic solvents in chemical analysis

Andrey Shishov, Leonid Moskvin, Andrey Bulatov
Department of Analytical Chemistry, Institute of Chemistry, Saint Petersburg State University, Saint Petersburg, Russia

Deep eutectic solvents (DES) have recently been increasingly used in many fields of chemical science, including analytical chemistry. DESs are generally composed of two or three cheap components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower that of each individual component. DESs, since the onset of their introduction, have received considerable attention due to their low cost, easy preparation and environmental friendliness.
Usually, in chemical analysis, DESs are used as cheap and effective extractants or solvents, which can often replace organic solvents or ionic liquids. However, in this their potential is not limited. This report presents a new options for the application of DES in chemical analysis. The possibilities of using not only the ready-made DES as extractants, but also extraction due to the formation of DES in-situ are shown. In addition, the possibility of using DES as an effective dispersant in dispersive liquid-liquid microextraction and using DES in flow analysis is shown. Also, the report will address general issues of terminology and potential new uses of DES in chemical analysis.
Acknowledgement: The authors gratefully acknowledge financial support from the Russian Science Foundation (project no. 16-13-10117) for financial support.



Keywords: deep eutectic solvents, extraction





OPY-014

Fully Inkjet-printed Hydrazine Sensor based on ZnO Nanoparticles-modified PEDOT:PSS electrode on Paper

Tutku Beduk, Eloise Bihar, Khaled Nabil Salama
Electrical and Mathematical Science and Engineering Division, King Abdullah University of Science and Technology, Jeddah, Saudi Arabia

In this work, we have developed a sensor device on a paper substrate by using inkjet printing technology which is a convenient method that allows controlled deposition of a variety of electronic materials in a customized geometries at low temperatures. Most electrochemical hydrazine sensors lack of portability and need expensive electrodes, which makes essential to build simple, user-friendly, cheap electrochemical setup and design portable sensor devices. Here we have used conducting polymer poly(3,4 ethylenedioxythiophene) doped with polystyrene sulfonate, (PEDOT:PSS) as a counter, working, and reference electrodes of the sensor. As the recent studies have shown that the use of nanomaterials to fabricate electrochemical-based sensors have improved the sensing performance due to increasing the surface area and catalytic ability for oxidation reactions. For instance, we have utilized ZnO nanoparticles deposition by inkjet printing method to improve sensing ability of the fabricated sensor device. Hydrazine sensing performances of the printed sensor was evaluated before and after modifying the working electrode of the device by inkjet printed ZnO nanoparticles. The enhanced electron transfer, sensitivity, stability and electrocatalytic activity of printed sensor after ZnO nanoparticle modification indicates that the fabricated device has good and selective sensing ability towards hydrazine. This fully printed, easy to fabricate device exhibits high sensitivity, a linear response in the concentration range of 0.01 -10 mM, and lower detection limit (~6 µM) towards hydrazine. Other features include a highly reproducible, fast fabrication process, stability, and selectivity.



Keywords: biosensor, chemical sensor, inkjet printing


Schematic view of inkjet printed hydrazine sensor







OPY-015

Solid phase microextraction of ibuprophen in human plasma with a new magnetic carbon dot/graphene oxide hybrid (Fe3O4@ND@GO) material by hplc-uv

Dönay Yuvalı, Erkan Yılmaz, Ibrahim Narin
Deparment of Analytical Chemistry, Erciyes University, Kayseri, Turkey

A simple, sensitive and rapid magnetic solid phase microextraction was developed and validated for the quantification of Ibuprofen (IBU) in human plasma. Determination of IBU after magnetic solid phase extraction (MSPE) was carried out by HPLC-DAD system The proposed method is based on simple and sensitive seperation of IBU by using magnetic solid phase extraction with new developed magnetic carbon dot/graphene oxide hybrid (Fe3O4@CD@GO) material as an adsorbent. Experimental variables affecting the extraction efficiency of IBU such as pH, amount of adsorbent, eluent type and volume, extraction time and were studied and optimized. The morphology, composition, and properties of the synthesized hybrid material was characterized by Fourier transform infrared spectrometry (FT-IR), Raman spectrometry (Raman), X-ray diffraction spectrometry (XRD), scanning electron microscopy (SEM) analysis. Under optimized conditions, linear range was ranged from 0.05 to 2.0 µg mL−1 with R2 of 0.9979. The limit of detection (LOD) was 8.0ng mL−1 and the recoveries at three spiked levels in human plasma were ranged from 90.0 to 96.0 % with the relative standard deviation (RSD) less than 4.0 % (n = 6). The results show that the combination MSPE with HPLC-DAD is a simple, rapid and sensitive method for the determination of ibuprofen concentration in human plasma.
This work has been supported by Erciyes University Scientific Research Projects Coordination Unit with research project TDK-2016-6823. The research project has been proved by Erciyes University Clinical Researchs Ethics Committee.



Keywords: Ibuprofen, magnetic hybrid material, magnetic solid phase extraction


Figure 1. Schematical diagram of the developed Spme procedure



Figure 2.IR spectrum of magnetic material

The morphology, composition, and properties of the synthesized hybrid material was characterized by Fourier transform infrared spectrometry (FT-IR), Raman spectrometry (Raman), X-ray diffraction spectrometry (XRD), scanning electron microscopy (SEM) analysis.


Figure 3. Sem image of magnetic material



The plasma concentration of ibuprofen in patient blood samples

Blood samples were taken at different time periods from volunteer patients that using ibuprofen 400 mg and different drugs, were applied our developed SPME method. Then samples were analyzed with HPLC-DAD. Patient A is a male and 23 years old. Patient B is a female and 22 years old. Result of analysis were presented in figure.


Table 1. Comparison of the developed method with literature
Extraction methodDetemination
method
Sample matrixLOD
%RSDRef.
HF-LPMEHPLC-UVHuman urine40.0 ng/ml1.815
LPEGC-MSEquine urine15.2 ng/ml4.416
Solid Bar MicroextractionHPLC-DADHuman urine0.36 ng/ml5.717
µLPMEHPLC-DADbiological and environmental samples100-500 ng/ml3.018
LPEHPLC-FLDhuman plasma33.3 ng/ml5.619
SPEHPLC-UVhuman plasma510.0 ng/ml2.320
Single-step liquid-liquid extractionUPLC-MS/MShuman plasma1ng/ml7-11.021
The proposed methodHPLC-UVhuman plasma8 ng/ml3.5this work






OPY-016

Corrosion detection on diamond-like carbon coated waveguides using iron sensitive dyes

Dervis Türkmen1, Carina Dettenrieder1, Mikael Karlsson2, Lars Österlund2, Fredrik Nikolajeff2, Boris Mizaikoff1
1Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
2Department of Engineering Sciences, Uppsala University, Uppsala, Sweden

Since the industrialization in the 18th century, iron became one of the most commonly used materials around the world and plays an important role in cast iron and steel production. These two materials are main components in the manufacturing and machinery sector, engineering industries, transportation equipment like the automobile, ship and railway manufactory. In addition, it is indispensable in the reinforcement system of concrete technology as used on construction sites for buildings and bridges. Besides a various application range, they all share the main problem of iron corrosion which can lead to a defective product, and to a massive safety problem.
Corrosion processes can be detected by electrochemical methods like electrochemical impedance spectroscopy (EIS). Due to its various evaluation methods the EIS is very time-consuming and needs also good knowledge in electrical engineering. Furthermore, this method is widely limited to laboratories-based measurements [1].

An alternative method, which is not commonly used, is attenuated total reflection infrared (ATR-IR) spectroscopy. ATR-IR spectroscopy is advantageously due to application in various devices which are not confined to laboratory use [2,3]. As an internal reflection element (IRE) diamond-like carbon (DLC) coated waveguides can be applied. DLC coated waveguides are mechanically robust, chemically inert combined with a high refractive index, and a broad optical transparency in the mid-IR spectral region [4].

Within this study, DLC chips (1cm x 1cm) were coated with an iron sensitive dye and analysed using ATR-IR spectroscopy. Therefore, the dye coated chips were briefly exposed to an iron(III) solution and dried out for at least 24 hours. A subsequent measurement showed that corrosion processes are perfectly capable of being detected by the use of ATR-IR spectroscopy combined with DLC coated waveguides.

References
1 J.-G. Guan, Y.-Q. Miao and Q.-J. Zhang, J. Biosci. Bioeng., 2004, 97, 219–226.
2 D. Sorak, L. Herberholz, S. Iwascek, S. Altinpinar, F. Pfeifer and H. W. Siesler, Appl. Spectrosc. Rev., 2012, 47, 83–115.
3 M. Allendorf, A. Subramanian and L. Rodriguez-Saona, JAOCS, J. Am. Oil Chem. Soc., 2012, 89, 79–88.
4 X. Wang, M. Karlsson, P. Forsberg, M. Sieger, F. Nikolajeff, L. Österlund and B. Mizaikoff, Anal. Chem., 2014, 86, 8136–8141.



Keywords: IR-ATR spectroscopy, corrosion detection, diamond-like carbon waveguide


A) A DLC chip ready to dry that has recently been coated with a 2,3-Dihydroxypyridine solution. B) IR spectrum of the dye coated chip before and after being exposed to an iron(III) solution.







OPY-017

Fusion strategy of Raman, NIR, MIR and SIFT-MS data to quantify extra virgin Argan oil adulteration

Mourad Kharbach1, Johan Viaene1, Joeri Vercammen3, Abdelaziz Bouklouze2, Yvan Vander Heyden1
1Department of Analytical Chemistry, Applied Chemometrics and Molecular Modelling, CePhaR, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, B-1090 Brussels, Belgium
2Pharmaceutical and Toxicological Analysis Research Team. Laboratory of Pharmacology and Toxicology, Faculty of Medicine and Pharmacy, University Mohammed V- Rabat- Morocco
3Interscience, Avenue J.E. Lenoir 2, 1348 Louvain-la-Neuve, Belgium

Extra virgin Argan oil (EVAO) adulterated with various less expensive vegetable oils represents a danger for consumers’ confidence and exportation. Spectrometric techniques have already been applied to detect Argan oil adulteration with other oils [1-2], but it was found a necessity to develop more robust and accurate models. Therefore, this work investigated the combination of Raman, mid infrared (MIR), near infrared (NIR), and selected-ion flow-tube mass-spectrometry (SIFT-MS) data for the quantification of Argan oil mixed with lower quality olive or sunflower oil in EVAO blends. Partial least squares (PLS) and support vector machine regression (SVMR) multivariate calibration models were established to predict the concentration of the adulterant. Models were fitted after using convenient correction and preprocessing techniques to the data. Three data fusion strategies (low-, mid- and high level) were applied to extract advantageous information from the Raman, MIR, NIR and SIFT-MS spectra. Interval-PLS (iPLS) and Variable Importance in Projection (VIP) were used to extract features for low and mid-level data fusion. The best models were selected and assessed based on evaluation parameters (R2, Q2, and the root-mean-squared errors of calibration, validation and cross-validation). The individual Raman, NIR, MIR, SIFT-MS and the data fusion models were also compared for their R2, Q2 and root-mean-squared errors of calibration, validation and cross-validation. The mid- and high-level data fusion provided better models for adulteration purposes.
The results showed that: (1) Raman, NIR, MIR and SIFT-MS are fast and non-destructive testing tools to quantify EVAO adulteration. (2) Different strategies of data fusion may effectively improve and enhance the resulting model prediction accuracy, and (3) data fusion can be applied as a potential tool for quantitative analysis.

References
[1] Oussama, A., Elabadi, F., & Devos, O. (2012). Analysis of argan oil adulteration using infrared spectroscopy. Spectroscopy Letters, 45(6), 458-463.
[2] Stokes, T. D., Foteini, M., Brownfield, B., Kalivas, J. H., Mousdis, G., Amine, A., & Georgiou, C. (2018). Feasibility assessment of synchronous fluorescence spectral fusion by application to argan oil for adulteration analysis. Applied spectroscopy, 72(3), 432-441.



Keywords: Extra Virgin Argan Oil, Adulteration, Multivariate calibration techniques





OPY-018

Comparative study of the quantitative performances of conventional and SORS handheld Raman spectrophotometers

Mohammed Alaoui Mansouri1, Pierre Yves Sacré1, Abdelaziz Bouklouze2, Philippe Hubert1, Roland Marini1, Eric Ziemons1
1University of Liege (ULiege), CIRM, Vibra-Santé HUB, Laboratory of Pharmaceutical Analytical Chemistry, CHU, B36, B-4000 Liege, Belgium
2Bio-Pharmaceutical and Toxicological Analysis Research Team, Laboratory of Pharmacology and Toxicology, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco

Handheld Raman spectroscopy is actually booming. Recent devices aim at addressing the usual Raman spectroscopy issues: fluorescence with shifted‐excitation Raman difference spectroscopy (SERDS), poor sensitivity with surface enhanced Raman scattering (SERS) and only surface information with spatially offset Raman spectroscopy (SORS). While qualitative performances of handheld devices are generally well established, the quantitative analysis of pharmaceutical samples remain challenging.
The aim of this study was to compare the quantitative performances of three commercially available handheld Raman spectroscopy devices. Two devices (ThermoFisher’s Truscan and Ocean Optic’s IDRaman mini) are equipped with a 785 nm laser wavelength and operate in a conventional backscattering mode. The IDRaman has the Orbital Raster Scanning (ORS) option to increase the analyzed surface. The third device (Agilent’s Resolve) operates with a 830 nm laser wavelength both in a backscattering mode and in the SORS mode.
The comparative study was carried out on ibuprofen-mannitol-microcrystalline cellulose ternary mixtures. The concentration of ibuprofen ranged from 24 to 52 % (m/m) while proportions of the two excipients were varied to avoid cross-correlation as much as possible. Analyses were performed directly through a glass vial and with the glass vial in a polypropylene flask using a validated FT-NIR spectroscopy method as a reference method. Chemometric analyses were carried out with the Partial Least Squares Regression (PLS-R) algorithm. The quantitative models were validated using the total error approach and the ICH Q2R1 guidelines with +/- 15% as acceptance limits.



Keywords: SORS, Raman, Partial Least Squares





OPY-019

Probing natural phenolic compounds by EPR spectroscopy – a prooxidant assay

Augustin Mot1, Cezara Zagrean Tuza2, Tomasz Chemiel3, Attila Bende1, Ioan Turcu1
1National Institute for Research and Development of Isotopic and Molecular Technology, Cluj-Napoca, Romania
2Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Cluj-Napoca, Romania
3Department of Analytical Chemistry, Faculty of Chemistry, Gdansk University of Technology, Gdańsk, Poland

Natural (poly)phenolic compounds are phytoconstituents widely distributed in fruits, vegetables and their processed products—juices, nectars, dried fruits or vegetables, powder fruit-based products— and are well known for their major wholesome biological activities such as cardioprotective, antithrombotic, anticancer, antioxidant, anti-inflammatory and others. Important classes of phenolic compounds include hydroxybenzoic and hydroxycinnamic acids, lignans, stilbenes and the most valuable class—flavonoids—which is divided in subgroups such as anthocyanins, flavonols, flavanols and others. Despite the fact that natural (poly)phenolic compounds may be identified and quantified employing different analytical methodologies and equipments, such as HPLC coupled with diode array, fluorescence, MS/MSn and TOF-MS detectors, interests have been shown in analytical methods that allow fast and efficient determination of total content of individual (poly)phenolic classes, without prior separation. Numerous assays have been reviewed from both analytical and chemical standpoints, with their advantages and limitations1.
However, some of the well-known antioxidants—ascorbic acid, vitamin E, flavonoids—might act as prooxidants, either due to the presence of a heavy metal or simply owing to their radical-based intermediates2. In this work, we’ll present a newly improved assay for prooxidant determination by using our previously proposed method3 that involved in-situ enzymatically generated phenolic-based radicals and monitoring their capacity to oxidize ferrous hemoglobin to methemoglobin, by means of visible molecular absorption spectroscopy. This physiologically-relevant assay corroborated with EPR spectroscopy data of semiquinone anion radicals, generated in alkali medium. Tentative mechanism of the generation of these radicals—together with their practical implications—will be presented. The analytical methods were applied on both pure relevant compounds, alone or in mixtures, as well as on real food-based samples. Evidence advocating analysis directly on the sample without prior separation coupled with chemometric approaches—was shown. In addition, findings regarding sugar moieties influence upon the physico-chemical properties (pKa values, lipophilicity, redox potential), antioxidant and prooxidant capacities of phenolic-based glycosides compared to their aglycone, will also be presented.



Keywords: EPR spectroscopy, prooxidant assay, natural polyphenolics


Schematic presentation of the prooxidant assay







OPY-020

Investigation of the interaction mechanism of volatile organic compounds with Phthalocyanine derivatives via Raman spectroscopy and SAW-based sensors

Funda Kus1, Serpil Harbeck2, Ayse Gul Gurek3, Ilke Gurol1
1TÜBİTAK Marmara Research Center, Materials Institute, Kocaeli, Turkey
2TÜBİTAK Marmara Research Center, Institute of Chemical Technology, Kocaeli, Turkey
3Department of Chemistry, Gebze Technical University, Kocaeli, Turkey

Exhaled human breath contains volatile organic compounds (VOCs) that can be used as markers for certain diseases [1] and various sensing materials have been used to detect these marker compounds with the help of surface acoustic wave (SAW) transducers [2].
In our previous study, non-peripheral and peripheral Phthalocyanine (Pc) derivatives (Figure 1a) have been discussed for their sensitivity and selectivity towards VOCs such as n-hexane, toluene and chloroform (Figure 1b) [3]. In this study, Pc compounds coated over SAW sensor devices by electro-spraying technique will be investigated via Raman spectroscopy in order to understand the interaction mechanisms under exposure to VOCs and identify the effect of active sites of the molecules on sensor signal. Similar studies to understand sensing molecule and analyte interaction have been performed previously via FT-IR [4-6].
In this study, the characteristics of these sensors will be investigated with selected analytes for the spectroscopic investigations that will be performed in ppm range relying on our previously published papers [3,5]. Additionally, the experiments will be performed both in dry and humid atmospheric conditions for the determination of the humidity influence on the interaction mechanisms.

References
1. T. Mathew, P. Pownraj, S. Abdulla, B. Pullithadathil, “Technologies for Clinical Diagnosis Using Expired Human Breath Analysis” Diagnostics, 2015.
2. A. Mujahid, F.L. Dickert “Surface Acoustic Wave (SAW) for Chemical Sensing Applications of Recognition Layer” Sensors, 2017, 17, 2716.
3. F. Kus, C. Tasaltin, M. Albakour, A.G. Gurek, I. Gurol, “Macromolecular Hexa-Asymmetric Zinc(II) Phthalocyanines Bearing Triazole-Modified Triphenylene Core: Synthesis, Spectroscopy and Analysis towards Volatile Organic Compounds on Surface Acustic Wave Devices” Journal of Porphyrins and Phthalocyanines, 2019, Accepted Paper.
4. R.C. Thomas, A. Hierlemann, A.W. Staton, M. Hill, A.J. Ricco, Reflectance infrared spectroscopy on operating surface acoustic wave chemical sensors during exposure to gas-phase analytes, Anal. Chem. 71 (1999) 3615–3621.

We would like to thank for financial support to TÜBİTAK (ARDEB Grant No: 115E045)
5. S. Harbeck, Ö.F. Emirik,I. Gürol,A.G. Gürek, Z.Z. Öztürk,V.Ahsen, Understanding the VOC sorption processes on fluoro alkyl substituted phthalocyanines using ATR FT-IR spectroscopy and QCM measurements, Sens. Actuat. B Chem. 176 (2013) 838–849.
6. S. Harbeck, D. Atilla, I. Dülger, M. Harbeck, A. G. Gürek, Z. Z. Öztürk, V. Ahsen. “The role of hydrogen bonding in the sensitivity of QCM sensors: A spectroscopic study on tosylamido phthalocyanines” Sensors and Actuators B 191 (2014) 750–756.



Keywords: phthalocyanine, surface acoustic wave, Raman


Fıgure_1







OPY-021

''Chemical composition and cytotoxic activity of Colchicum cilicicum from Turkey''

Gizem Gulsoy Toplan1, Çağlayan Gürer1, Serpil Demirci2, Afife Mat1, Günay Sarıyar3
1Istanbul University, Department of Pharmacognosy, Facult of Pharmacy, Beyazıt Istanbul, Turkey
2Çukurova University, Department of Pharmaceutical Botany, Facult of Pharmacy, Adana, Turkey
3International Cyprus University, Department of Pharmacognosy, Facult of Pharmacy, Lefkoşa, Cyprus

Turkey is regarded as one of the richest sources of Colchicum species which are very important in treatment. Members of Liliaceae (Colchicaceae) family, they are known for their therapeutic importance for over 2000 years. The tropolon class alkaloids in Colchicum sp. hold important place in treatment of FMF, Behcet’s disease, cirrhosis, lymphoid leukemia, Hodgkin’s, psoriasis and are also essential in inducing polyploidy in plants. C. autumnale, which grows only in Europe, is the sole source of colchicine and the other tropolon alkaloids. However, because C. autumnale fails to meet the needs alone, new resources are being sought by the pharmaceutical industry. The researches conducted on chemical contents of Colchicum sp. in our country showed that some species contained high amount of tropon alkaloids similar to or higher than C. autumnale. As a result, the species containing high amounts of alkaloids (especially C. speciosum), began to be exported. The presence of a wide variety of Colchicum species in Turkey has driven researchers to find new sources of Tropolon alkaloid-rich species. In the present work, alkaloids and cytotoxic activities from different parts of Colchicum cilicicum were investigated for the first time. The methanol extracts were investigated for their cytotoxic activity against the A549, MCF-7, PC-3 and HT-29 cell lines using the SRB method. As a result, six alkaloids, namely colchicine, colchifoline, 2-demethylcolchicine, 3-demethylcolchicine, demecolcine, and N-deacetyl-N-formylcolchicine were isolated from different parts of the species. As to cytotoxic activity, the methanol extracts of different parts of C. cilicicum, showed moderate to strong activity against A549, MCF-7, PC-3 and HT-29 cell lines. This is the first report on the alkaloid contents and cytotoxic activity of C. cilicicum extracts.



Keywords: cytotoxic activity, alkaloids, isolation





OPY-022

The dsDNA binding studies of novel flavonoid derivatives via sequential sulfation of apigenin

Pelin Şenel1, Büşra Yıldırmaz1, Simon N. Waihenya2, Omowunmi A. Sadik2, Ayşegül Gölcü1
1Department of Chemistry, Faculty of Science and Letters, Istanbul Technical University, Maslak, Istanbul, Turkey.
2Department of Chemistry, Center for Research in Advanced Sensing Technologies & Environmental Sustainability (CREATES), State University of New York, at Binghamton,USA.

Flavonoids are naturally-occurring polyphenolics that have been implicated in a wide range of biologicalactivities1. The major obstacles to flavonoid applications are the poor solubility in common solvents. Sulfation of flavonoids yields a new class of flavonoid derivatives which are very soluble in aqueous solutions and hence have the potential to be used in biological studies. We hereby report the sequential sulfation of apigenin leading to the synthesis of apigenin tritasulfate (2stELT) (Scheme 1) and studied dsDNA binding studies using UV absorption spectroscopy, thermal denaturation, fluorescence and FTIR spectroscopy, and as well as electrochemical measurement method on double stranded DNA (dsDNA) under the physiological pH 7.4 conditions at room temperature. In conclusion, we hereby propose the possible binding mechanisms for apigenin and its derivative.



Keywords: Flavonoid, apigenin derivatives, double stranded fish sperm DNA


Propose structure of 2stELT







OPY-023

Electroanalysis of pharmaceutical compounds

Rafaela Cristina De Carvalho1, Anthony J Betts1, John F Cassidy2
1Applied Electrochemistry Group, FOCAS Research Institute Technological University Dublin, City Campus, Kevin Street, Dublin DO8 NF82, Ireland
2School of Chemical and Pharmaceutical Sciences Technological University Dublin, City Campus, Kevin Street, Dublin D08 NF82 Ireland

The Screen printed carbon electrode-CeO2 approach shows many advantages over other electrochemical sensors reported in the literature; notably a simple fabrication process, the possibility of large scale-production, low-cost, portability, and the potential for use over wide concentration ranges of acetaminophen (ACOP), acetylsalicylic acid acid (ASA), caffeine (CAF) and diclofenac (DCF). Consequently, this method is worth consideration for both the individual and the simultaneous determination of all three molecules at trace levels in clinical and quality control laboratories. A LOD of 0.4 µmoL and sensitivity of 0.058 µA/µM were determined for DCF. The fabricated electrodes demonstrated superior reproducibility, with R.S.D of 2.7% even with a primitive casting of CeO2 on the electrode surface.



Keywords: CeO2, electroanalysis, screen-printed-electrode





OPY-024

Renal localization and quantification of uranium in rodent exposed to uranyl nitrate by LA-ICP-MS

Nagore Grijalba, Alexandre Legrand, Valerie Holler, Celine Bouvier Capely
PSE/SANTE/SESANE/LRSI, Institut de Radioprotection et Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France

The over-exposure to uranium results in renal toxicity, which is derived form an excessive accumulation of the element in the kidney, characterized by reduced glomerular filtration, exerting its toxic effect by chemical and radiological action. In addition, its tissue distribution is heterogeneous mostly accumulating and producing pathological lesions in the S2 and S3 segments of the proximal tubule located in the cortical zone (100-fold above mean renal concentration). Chronic exposure (occupational exposure) to uranium, is linked to its bioaccumulation in kidney and could be associated with renal dysfunction, an increased risk of cancer mortality and kidney failure. Up to day, few quantitative studies have been carried out employing high-energy synchrotron radiation X-ray fluorescence analysis (SR-XRF) and X-ray absorption fine structure (XAFS). Unfortunately, the limited access to these analytical techniques limits considerably its daily use for routine analysis. Therefore, this works presents the development of an analytical methodology based on mass spectrometry imaging (MSI) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for mapping and quantifying uranium in histological tissue sections of mouse kidney. To the author’s knowledge a single work has been published recently for the semi-quantitative analysis of uranium in mice kidneys due to the lack of an appropriate internal standard.

In this study, the uranium exposure of mice was performed using a direct nasal instillation of few µL of uranyl nitrate solutions at different uranium concentrations. Total uranium analysis was done by conventional liquid ICP-MS after acid digestion using one kidney from each pair. In parallel, the other kidney was employed for LA-ICP-MS analysis. In order to perform quantitative LA-ICPMS bio-imaging analysis, synthetic matrix-matched laboratory standards and a normalisation strategy based on internal standard spiked gelatine were developed. Preliminary quantitative images of cryo-sections revealed heterogeneous distribution of uranium within the renal tissue, being the cortical concentration 60-fold higher than the medullary concentration.



Keywords: LA-ICP-MS, bioimaging, uranium





OPY-025

In-Situ STEM Analysis of Gold Nanoparticles to Understand Nu-cleation and Crystal Growth

Cansu Zeliha Canbek Özdil1, Fabienne Testard2, Damian Alloyeau3, Guillome Wang3, Christian Ricolleau3, Olivier Spalla2, Nicolay Menguy4
1Computer Engineering Department, Bogazici University, 34342 Istanbul, Turkey
2CEA Saclay, DSM/IRAMIS/NIMBE/LIONS, UMR CEA/CNRS 3685, 91191 Gif sur Yvette, France
3Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS/Université Paris - Diderot, 10 rue Alice Domon et Léonie Duquet, 75013 Paris, France
4Université Pierre et Marie Curie, IMPMC, UMR 7590 CNRS, Campus Jussieu, 75252 Paris Cedex 05, France

Liquid state transmission electron microscopy is a recent technique allowing researchers to visualize the nanoparticles directly in their liquid environment. Accurate visualization of growth in small nanoparticles is desired yet a challenging process due to limited resolution obtained due to surfactant present in the system. In this work, by using liquid environmental cell specimen holder (e-cell), developed for scanning transmission electron microscopy, we were able to monitor the formation of anisotropic gold nanoparticles from small precursors (< 7 nm) in surfactant assisted media, under electron beam. Technique offers the possibility to probe nanoparticles in-situ and to obtain detailed information on how nanoparticles grow in solution. However, under electron beam irradiation, due to radiolysis of water, some radicals are produced which can interact with the reactants and modify the chemical processes. Such phenomenon has to be considered during in-situ STEM analysis. In case of gold, this prior drawback can also be used to control the reaction. In our work, the incident electron beam was chosen to achieve two tasks simultaneously; first, as a radiation source to induce the radiolysis of water (which is responsible for the reduction of gold precursor) and the second, it allows the real time imaging of particles of interest in a thin layer of liquid. Initially, we have described influences of the beam parameters and the chemical conditions on the final shape of nanoparticles. Between these parameters, in case of altering the magnification (i.e. the dose rate), we have observed major differences in the shape of final nanoparticles obtained. Regarding to these differences, following formation mechanism has been proposed; at low dose rate, few number of produced seeds are able to grow into branched nanoparticles due to slow kinetics, caused simultaneously by slow ascorbic acid reduction at the surface of the nanoparticles and low number of radicals induced by electron beam, while at higher dose rate, the concentration of strong reducing agent is so high that the alimentation of the seeds will certainly proceed initially by fast feeding by pre-reduced Au(0) due to aqueous electrons and strong reducing agent and the slow feeding due to ascorbic acid reduction at the surface of the particles. Additionally, the structure of final nanoparticles obtained by in-situ STEM and by gamma irradiation source (at similar chemical compositions) is compared to demonstrate the crucial importance of beam parameters on nanoparticle morphology.



Keywords: In-Situ STEM, Crystal Growth, Gold Nanoparticles


Figure 1

Above - Time resolved sequential images of Au NP growth at magnification 250k and pixel time 2 µS Below - Evolution of a) length b) diamater of four distiguished bipyramids c) diameter of four nanostars with time obtained at dose rate of 1.40 e-/sÅ2 d) Variation of the number of particles in unit area (nm2) with time






OPY-026

Container-content interactions study in the cosmetic industry: chemical and toxicological approach

Pauline Murat1, Pierre Jacques Ferret3, Sylvie Coslédan1, Valérie Simon2
1Chimie Analytique et Compatibilité, Pierre Fabre Dermo-Cosmétique, Vigoulet-Auzil, France
2Laboratoire de Chimie Agro-Industrielle (LCA), Univeristy of Toulouse, INRA, INPT, Toulouse, France
3Sécurité Produits et Cosmétovigilance, Pierre Fabre Dermo-Cosmétique, Toulouse, France

Plastics are nowadays the principal materials used for cosmetic packagings. Indeed, they present many advantages such as low price, flexibility and resistance. However, these materials present a real environmental problematic. Moreover, due to their polymeric matrix, compounds such as additives (colorant, ink, plasticizers…) and non-intentionally added substances (also called NIAS) can migrate from the material into the cosmetic products. This phenomenon, called container-content interactions, is well studied in the industries of food, pharmaceutical products and medical devices. However, it is still unusual to see that kind of study on cosmetic products such as shampoo or lotion that are used daily. The possible carcinogenic, mutagenic or reprotoxic properties of the migrating molecules, called extractables and leachables, could potentially affect products’ innocuousness, highlighting the importance of such study in the cosmetic area.
The aim of this work is to present a strategy of container-content interactions applied to cosmetic products. Combining material science, toxicology and analytical chemistry, a comprehensive analysis is used to screen a large spectrum of potential extractables and leachables for seven packaging materials (made up of polyethylene, polypropylene or styrene-acrylonitrile copolymer). The strategy developed is a multiple step strategy.
The first step, inspired from the European strategy for container-content interactions study in foodstuff, involves the use of simulants, i.e. simple matrices that mimic cosmetic products, for migration studies. Simulants proposed by the European food regulation were adapted to cosmetic products. In this way, seven simulants divided into two categories were identified: aqueous/ethanolic (Murat et al., 2019) simulants and viscous simulants (glycerin and liquid paraffin). They were put in contact with plastic packagings for one month at 50°C. Twelve targeted compounds such as phthalates and plastic additives and twelve elements such as lead, arsenic and cadmium are qualified and quantified respectively using GC-QMS, LC-UV and ICP-MS according to a list of potential extractables and leachables pre-established by toxicologists. A screening study is also led by GC-TOF to identify potential unknown migrating compounds. For viscous simulants, different extraction METHODS: liquid-liquid extraction, liquid-liquid micro-extraction and solid phase micro-extraction were tested and compared in term of efficiency, environmental impact and practicality. All the results obtained were compared with toxicological thresholds set using reference values.
The second step is to study directly the packaging materials themselves. Extraction method prior to GC-MS/FID analysis was applied to packaging thanks to thermodesorption in order to analyze potential compounds leached directly from the source. A characterization of the materials was also made using thermal analysis such as differential scanning calorimetry to determine physico-chemical characteristics. These properties were helpful to explain the results obtained from simulants analyses.
Conclusions were made on the compatibility between a cosmetic product and a packaging material in order to ensure the safety of the consumers.

Murat, P., Ferret, P.-J., Coslédan, S. & Simon, V. Assessment of targeted non-intentionally added substances in cosmetics in contact with plastic packagings. Analytical and toxicological aspects. Food Chem. Toxicol. (2019). doi:10.1016/j.fct.2019.03.030



Keywords: Container-content interactions, cosmetics, phthalates


Container-content interactions study in cosmetics







OPY-027

Electrochemical sensors based on 2D carbon materials: impact of the fabrication method on the performance

Eva-Maria Kirchner, Thomas Hirsch
Institute of Analytical Chemistry, Chemo- and Biosensors, University of Regensburg, Regensburg, Germany

Carbon nanomaterials, especially the 2D modifications, turned out as attractive alternative to noble metals as electrodes in analytical applications. This is mainly attributed to the low cost, the chemical stability, the wide electrochemical window and the ease of functionalization. Even when it is not too difficult to fabricate 2D carbon materials by top-down approaches from graphite, all these methods result in different allotropes when looking at its nano dimensions. Size, number of layers and defects have a huge impact on the electrochemical performance. Therefore, we present a systematic study on graphene prepared from graphite by application of mechanical (meG) or electrical (ECG) forces compared to reduced graphene oxide (rGO) known as very defective material and graphene obtained from a chemical vapor deposition (CVD) process which leads to monolayer material of almost no defects. We fully characterized all those carbon nanomaterials and studied the influence of flake-size distribution, the number and type of defects on their electrochemical properties. It was found, that rGO shows the fastest heterogeneous electron transfer indicated by a three times smaller peak separation for rGO compared to non-defective CVD. The charge transfer resistance of rGO and meG is three times higher compared to CVD. It turned out that the fast heterogeneous electron transfer between defective carbon materials and potential analytes, together with the low charge transfer resistance are the key parameters when using those materials in electrochemical sensors. Furthermore, we can show a fast method by statistical Raman spectroscopy to correlate the material properties with their electrochemical features.



Keywords: graphene, sensor, raman


Scheme of the deposition process of graphene materials to modify interdigitated gold electrodes.







OPY-028

GUMBOS and nanoGUMBOS: synthesis and sensing applications for protein analyses

Ana M.O. Azevedo1, Mi Chen2, Caitlan E. Ayala2, Rocío L. Pérez2, João L.M. Santos1, M. Lúcia M.F.S. Saraiva1, Isiah M. Warner2
1LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal
2Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States

The flexible properties of ionic liquids (ILs) and their wide range of applications have prompted the development of a group of uniform materials based on organic salts termed GUMBOS. These materials share similar properties to those of ILs but have a defined melting point range of 25–250 ºC. Although solid-phase, GUMBOS also possess broad tunability achieved by varying the constituent ions, which make them interesting candidates for various analytical, biomedical, and materials applications. NanoGUMBOS are nanomaterials derived from GUMBOS, which take advantage of the versatility of these solid-state compounds and improved features obtained at nanoscale [1].
In this work, we report the synthesis and characterization of a series of xanthene-based GUMBOS and nanoGUMBOS for potential sensing applications. These GUMBOS were prepared via a simple metathesis reaction between the anionic dye erythrosin B (EB) and several ammonium, imidazolium, and phosphonium salts. In this context, EB serve as a fluorescent sensing probe, while cations aid in tuning hydrophobicity of GUMBOS, which may result in different interactions between GUMBOS and protein analytes. In addition, conversion of GUMBOS into nanoGUMBOS may lead to further increase of selectivity and sensitivity to specific proteins as compared to GUMBOS due to the unique physicochemical properties of nanomaterials. In this talk, we describe examples of applications of this strategy for analyses of proteins.

Acknowledgments: Ana M.O. Azevedo thanks FCT (Fundação para a Ciência e a Tecnologia) for her PhD grant (SFRH/BD/118566/2016). This work received financial support from the European Union (FEDER funds POCI/01/0145/FEDER/007265) and National Funds (FCT/MEC – Ministério da Educação e Ciência) under the Partnership Agreement PT2020 UID/QUI/50006/2013. Also, by FEDER Funds through the Operational Competitiveness Factors Program – COMPETE, and by National Funds through FCT within the scope of the project POCI-01-0145-FEDER-030163.

[1] Warner, I. M., El-Zahab, B., & Siraj, N. (2014). Perspectives on Moving Ionic Liquid Chemistry into the Solid Phase. Anal Chem, 86(15), 7184-7191.



Keywords: GUMBOS, Fluorescence sensing, Proteins





OPY-029

Exploiting ultrafiltration for purification and characterization of drug-nanocarriers

Sara S. Marques1, Ines I. Ramos1, Sara R. Fernandes1, Luisa Barreiros1, Sofia A. C. Lima1, Salette Reis1, Maria R. Domingues2, Marcela A. Segundo1
1LAQV, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Porto, Portugal
2Departamento de Química, CESAM & QOPNA, Universidade de Aveiro, Aveiro, Portugal

The evaluation of drug encapsulation efficiency in nanocarriers is a crucial parameter to assess quality, safety and possible therapeutic efficacy. The accomplishment of precise determinations depends on the efficient separation of nanoparticles from free drug while maintaining nanoparticle properties, and this is still a challenging task.

In this work, ultrafiltration was exploited for the purification and characterization of lipid and polymeric nanoparticles loaded with methotrexate (MTX). The effective encapsulation of this drug would potentiate long-term treatment in chronic inflammatory conditions. Due to MTX-associated toxicity along with the low encapsulation generally attained for hydrophilic compounds, nanoparticle purification and accurate determination of encapsulation efficiency were pursued.

The total amount of MTX present in formulations was assessed by HPLC-UV to monitor the quality and batch-to-batch consistency of the nanocarriers under study. Chromatographic separation was performed on a reversed-phase (C18) monolithic column using acetonitrile-phosphate buffer (pH 7.0, 100 mM) (9:91, v/v) as mobile phase. The analysis was performed at 1.5 mL min-1 with a total run time of 3.5 min and spectrophotometric detection at 302 nm. Similarly, MTX remaining in the upper compartment and MTX present in the obtained ultrafiltrate when nanoparticles were submitted to ultrafiltration were analyzed using this method.

Ultrafiltration was performed under different conditions, concerning pH and the quantity of surfactant (polyvinyl alcohol) used in the preparation media. Higher recoveries were attained for pH 7.0 in relation to lower pH, with 93.0 ± 0.1% of the recovered MTX present in the ultrafiltrate. Also, permeation values of 96 ± 3% and 62 ± 1% were attained for MTX when the preparation media contained 0.17 and 0.75 mg mL-1 of surfactant, respectively. Higher concentrations of surfactant hampered ultrafiltration efficiency, with a permeation of only 63% of the fed volume after 5 min of centrifugation for 0.75 mg mL-1 in comparison with the 90% attained for 0.17 mg mL-1 (MTX recoveries of 98 ± 3%).

Therefore, the dilution factor applied to the initial formulation and the centrifugation time required for the analysis of the lipid and polymeric nanoparticles under study were defined to accomplish effective separations within 30 min. The application of optimized conditions to pig skin surrogate from permeation studies and culture media prove the method suitability for nanoparticles purification and characterization in complex samples (pig skin surrogate and culture media), with an efficiency of nanoparticles purification from free MTX of 89 ± 1% and 93 ± 4%, respectively (recoveries > 94%).

Acknowledgments:
S. S. Marques acknowledges FCT (Fundação para a Ciência e a Tecnologia) for the PhD grant (PD/BD/128398/2017) supported through the FCT PhD Programmes and by Programa Operacional Capital Humano (POCH, ref. PD/00016/2012). I. I. Ramos and S.R. Fernandes thank FCT and POCH for their grants (SFRH/BD/97540/2013, SFRH/BD/130948/2017). Authors also acknowledge financial support from the European Union (FEDER funds POCI/01/0145/FEDER/007265) and National Funds (FCT/MEC) under the Partnership Agreement PT2020 UID/QUI/50006/2013 and FCT Grant UID/QUI/00062/2013.



Keywords: Nanoparticles, encapsulation, ultrafiltration





OPY-030

Preparation and comparison of electrospun matrice and hydrogel based controlled release systems for chemotherapeutic agent epirubicin and metal complexes

Veselina Adımcılar1, Filiz Altay2, Vural Bütün3, Ayşegül Gölcü1
1Istanbul Technical University, Faculty of Science and Letters, Department of Chemistry, 34469, Maslak, ISTANBUL
2Istanbul Technical University, Faculty of Chemical and Metallurgical Engineering, Department of Food Engineering, 34467, Maslak, İSTANBUL
3Eskişehir Osmangazi University, Faculty of Science and Letters, Department of Chemistry, 26480, Meşelik, ESKİŞEHİR

Designing drug release systems for sustained drug delivery was first introduced in 1952 for the oral intake of medications. The studies were gradually increased due to the many advantages of these systems, where the main purpose is maintaining drug concentration at blood or targeted tissues at an effective and non-toxic dose. These systems are not only decrease cytotoxicity and undesired side effects of the drug; but also improves effectivity and stability[1]. Biodegradable polymers and hydrogels have been using many medicinal applications including drug delivery. Hydrogels are made up of any type of water-soluble polymers, flexible, three-dimensional networks and can be prepared in any physical form and a wide range of drugs can be loaded into gels[2]. Furthermore, recent studies have been focussed on employement of elctrospinning technique for production of small diameter fibers. Electrospun materials, nano or microfibers as drug carriers serve high drug loading and encapsulation capabilities which also provides cost effective highly efficient systems due to compatibility with many polymers[3].
Metal-based compounds have had gained attention especially after the discovery of cis-platinium ([Pt(NH3)2Cl2]) by Rosenberg in 1969. Soon afterward the discovery, many research groups have been focussed on preparation novel metal-based compounds as potential anticancer agents under the root of the research field of study called ‘Medicinal Chemistry’ [4]. The point of view of these studies is the preparation of less cytotoxic and more effective drug molecules.
In this current study, the controlled release mechanisms of epirubicin (EPR) which is a currently using chemotherapeutic drug in anthracycline structure and its succesfully prepared and caharcaterized metal complexes which are EPR-Fe(III) and EPR-Pt(II) were investigated from two different contolled release systems. The release kinetics of metal complexes and epirubicin were investigated in different solutions with changing pH values by using UV-Vis Absorption spectrometer. The first controlled release system was prepared by loading of the drug and its complexes into the methacrylic acid based hydrogel. The polymerization was performed at 60℃ by using methylene bisacrylamide as a crosslinker in the presence of ammonium persulfate initiator. The second controlled release system was designed based on polyacrylic acid which was used as carrier polymer and EPR loaded material was successfully electrospun and the release mechanisms were also investigated. The obtained hydrogels and electrospun materials were characterized by using scanning electron microscopy technique(SEM). It is found that high pH values swelling and the drug release was considerably high compared to the acidic pH values. The obtained results were compared with the release kinetics of the epirubicin drug itself with the complexes and also between two different drug release systems.
References:
[1] Park K, The controlled drug delivery systems: Past forward and future back, Journal of Controlled Release, 2014, 190, 3-8.
[2] Hoare T R, Hydrogels in drug delivery: Progress and challenges, Polymer, 2008, 49, 1993-2007.
[3] Chou S F, Carson D, Woodrow K A, Current strategies for sustaining drug release from electrospun nanofibers, Journal of Controlled Release, 220(Pt B), 584–591.
[4] Rosenberg B, Platinium Metals Review, 1971, 15, 42–51.



Keywords: Epirubicin, Controlled Release Systems





OPY-031

Automatic methodologies to perform loading and release assays of anticancer drugs from mesoporous silicon nanoparticles

Sarah Pereira1, Marieta L C Passos1, Alexandra Correia2, Ermei Mäkilä3, Jarno Salonen3, André R. S. T. Araujo4, Hélder A. Santos5, M. Lúcia M. F. S. Saraiva1
1LAQV, REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, Porto University, Porto, Portugal
2Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland
3Laboratory of Industrial Physics, Department of Physics, University of Turku, Turku, Finland
4LAQV, REQUIMTE, Department of Chemical Sciences, Laboratory of Applied Chemistry, Faculty of Pharmacy, Porto University, Porto, Portugal and Unidade de Investigação para o Desenvolvimento do Interior, Instituto Politécnico da Guarda, Guarda, Portugal
5Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland and Helsinki Institute of Life Science (HiLIFE), University of Helsinki, Helsinki, Finland

The main goal of this study was to develop two automatic methodologies to perform the drugs loading and releasing from porous silicon (PSi) nanoparticles. We selected 5-Fluorouracil (5-FU) as a model drug and we used different functionalized PSi nanoparticles. Regarding drug loading, we explored the reproducible characteristics of flow systems considering mixture and volumes taken. For drug releasing, we tested the versatility in accommodating different devices around the valve. Fluorescent properties of 5-FU were used with detection limit of 9x10-4 mg L⁻¹ and a linear response up to 5 mg L⁻¹. The optimization of drug loading and releasing procedures in sequential injection analysis (SIA) systems allowed to save time (4 min towards 2 hours). Comparison of the different behaviours of the PSi nanoparticles with batch and SIA methods revealed absence of statistical differences (Student’s t-test for loading with a calculated t value of 2.04). All the results presented an RSD less than 10%. In conclusion, the developed automatic methodologies are a viable alternative to load drugs and to study the release profiles from PSi nanoparticles.

Acknowledgments
This work received financial support from the European Union (FEDER funds POCI/01/0145/FEDER/007265) and National Funds (FCT/MEC, Fundacao para a Ciencia e Tecnologia and Ministerio da Educacao e Ciencia) under the Partnership Agreement PT2020 UID/ QUI/50006/2018. Also by POCI-01-0145-FEDER-030163, financed by FEDER-Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020-Operational Programme for Competitiveness and Internationalization (POCI), Portugal 2020. Marieta L.C. Passos thanks FCT for the financial support. Helder A. Santos acknowledges financial support from the University of Helsinki Research Funds, the Sigrid Juselius Foundation (decision no. 4704580), the HiLIFE Research Funds, and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007–2013, grant no. 310892).



Keywords: mesoporous silicon nanoparticles, loading and release assays, automation





OPY-032

A new therapeutic agent for lung cancer: AuNP-CRGD conjugates

Melike Sarıçam
Department of Genetics and Bioengineering, Yeditepe University, Istanbul, Turkey

Lung cancer is one of the major cancer types for today’s world. Risks and limitations of chemotherapy and alternative treatment techniques for lung cancer fostered to search new cheap, effective, sensitive, specific and antibody free alternative lung cancer treatment. Nanomedicine is the application of nanosized nanomaterials in medicine. Gold nanoparticles (AuNPs) are one of the most promising and extensively studied nanoparticle for biomedical applications. After functionalization of their surfaces with biomolecules, they may gain significant properties to be used in biomedical applications. Thus, in this study, it was aimed to observe the affect of free terminus on custom designed AuNP conjugates. The spherical AuNPs of 13 nm diameter size were used as model NPs because of their unique optical properties, ease of synthesis and easy surface chemistry. The surface of AuNPs were coated with CRGD peptides, which enables high uptake of NPs. These peptides were designed as having opposite order and so having different free terminus whether -NH2 or -COOH end. By this way, the free terminus effect of AuNP-CRGD conjugates was investigated in A549 cells (human lung carcinoma cell line) and BEAS-2b cells (human bronchial cell line) to see their possible therapeutic effect. Therefore, A549 cells and BEAS-2b cells were treated with 0.1, 0.5, 1.0 and 2.5 nM of naked AuNPs, AuNP-CRGD-NH2 and AuNP-CRGD-COOH conjugates for 24h. after treatment, the cellular responses of either cancer cells or healthy cells were investigated by considering their uptake, cytotoxicity, effect on reproductive integrity and cell cycle progression. AuNPs functionalized with two RGD peptides resulted in various cellular responses in either A549 cells as cancer cell line or BEAS-2b cells as healthy cell line. AuNP-CRGD having -NH2 terminus was highly uptaken by A549 cells while AuNP-CRGD having -COOH terminus was significantly uptaken by BEAS-2b cells. Even though a severe concentration dependent cytotoxicity was observed in A549 cells treated with AuNP-CRGD-NH2, no cytotoxicity was seen in BEAS-2b cells after treatment with both conjugates. Additionally, AuNP-CRGD-COOH affected the reproductive integrity of A549 cells since they could not form colonies upon AuNP-CRGD-NH2 treatment, however BEAS-2b cells survived by forming colonies under that condition. Lastly, the cell cycle progression of A549 cells treated with AuNP-CRGD-NH2 was arrested in G0/G1 phase. It can be concluded that highly internalized AuNP-CRGD-NH2 dramatically influenced the A549 cells while the BEAS-2b cells were not upon its treatment, thus AuNP-CRGD-NH2 conjugate can be used as therapeutic agent for lung cancer cells.



Keywords: Gold Nanoparticles, Lung cancer, therapeutic agent





OPY-033

Novel and Rapid Strategy for the Synthesis of Decorated Nanostructured Magnetic Molecularly Imprinted Polymers using an Ultrasound Probe

Abdellatif Ait Lahcen1, Juan José García Guzmán2, José Maria Palacios Santander2, Laura Cubillana Aguilera2, Aziz Amine3
1Sensors Lab, Advanced Membranes and Porous Materials Center, Computer, Electrical and Mathematical Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Kingdom of Saudi Arabia
2Institute of Research on Electron Microscopy and Materials (IMEYMAT), Department of Analytical Chemistry, Faculty of Sciences, Campus de Excelencia Internacional del Mar (CEIMAR), University of Cadiz, Campus Universitario de Puerto Real, Polígono del Río San Pedro S/N, Puerto Real, Cádiz 11510, Spain
3Chemical Analysis & Biosensors Group, Laboratory of Process Engineering & Environment, Faculty of Science and Techniques, Hassan II University of Casablanca, B.P. 146. Mohammedia, Morocco

In many biological processes, the selective molecular recognition is considered as the key factor; since then, the basic principle and aim of molecularly imprinted polymers (MIPs) focused on the substitution of the natural receptors such as antibodies and enzymes by other biomimetic recognition elements based on synthetic receptors that attracted more attention by the scientific community.
MIPs are typically prepared via conventional reflux heating techniques. However, these thermal polymerization methods inevitably result in binding site heterogeneity due to gains in conformational entropy. Besides, they are also time consuming and need long MIP synthesis time time (12–24 h). Thus, the long time required for MIPs synthesis is a drawback and could limit their practical applications.
Recently, the ultrasound-assisted approach is introduced as an alternative and efficient method for MIPs synthesis instead of conventional thermal heating methods. The use of ultrasound-assisted based methods for the synthesis of magnetic MIPs shows many advantages such as the acceleration of the polymerization reaction rate and allows to generate more homogeneous polymer chain growth, greater yields, milder conditions and assists the formation of spherical nanoparticles.
Indeed, we report for the first time a novel, simple and fast method for the synthesis of magnetic molecularly imprinted polymers (Mag-MIPs) based on high-energy ultrasound probe. We have studied and optimized several parameters affecting the synthesis of Mag-MIPs such as the effects of time (5, 7.5 and 10 min) and the applied amplitude (20, 30, 40, 50 and 60%). Under optimal conditions, the proposed synthesis methods leads to the successful reduction of Mag-MIPs synthesis time from several hours to few minutes (7.5 min) in a simple way. For comparison purposes, the Mag-MIP and the non imprinted polymer (Mag-NIP) were also synthesized using a traditional approach based on ultrasound bath (2 h, 65 °C).
The synthesized Mag-NIPs and Mag-MIPs were characterized using Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Scanning/Transmission electron microscopy (SEM and STEM modes), Vibrating Sample Magnetometer (VSM) and Dynamic Light Scattering (DLS). The results obtained confirm clearly the successful decoration by the imprinted polymer in both synthesis ways.
The binding capacities of the synthesized Mag-MIPs towards sulfonamide were evaluated using adsorption isotherms using electrochemical sensor. The Mag-MIP synthesized with the ultrasound probe demonstrated high binding capacity compared to the one synthesized with Ultrasound bath. The adsorption time was studied and the results showed that both synthesized Mag-MIPs reached the maximum adsorption capacity toward SMX after 1 hour and the Mag-MIP synthesized using ultrasound probe tends to have more easiness to bind SMX in less time. The synthesized Mag-MIPs exhibits high towards sulfamethoxazole selectivity compared to its structural analogues such as sulfadiazine, sulfamerazine and sulfacetamide [1].

Keywords: High-energy ultrasound probe, Magnetic molecularly imprinted polymer, Electrochemical detection, Sulfonamides, Magnetic nanoparticles

References
[1] Lahcen, A.A., García-Guzmán, J.J., Palacios-Santander, J.M., Cubillana-Aguilera, L. and Amine, A., 2019. Fast route for the synthesis of decorated nanostructured magnetic molecularly imprinted polymers using an ultrasound probe. Ultrasonics sonochemistry. https://doi.org/10.1016/j.ultsonch.2019.01.008



Keywords: High-energy ultrasound probe, Magnetic molecularly imprinted polymer, Magnetic nanoparticles


Scheme 1. Schematic illustration of the synthesis of Mag-MIPs using High-energy Ultrasound probe

Please insert the scheme 1 in Abstract






OPY-034

The protein corona composition sheds light on the fate of intracellular gold nanoparticles

Gergo Peter Szekeres1, Nerea Fernandez Iglesias2, Janina Kneipp1, Jörg Bettmer2, Maria Montes Bayón3
1School of Analytical Sciences Adlershof, Berlin, Germany / Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
2Department of Physical and Analytical Chemistry, Universidad de Oviedo, Oviedo, Spain
3Department of Physical and Analytical Chemistry, Universidad de Oviedo, Oviedo, Spain / School of Analytical Sciences Adlershof, Berlin, Germany

The protein corona, i.e., the adsorbed protein layer on the surface of a nanoparticle forms spontaneously when a nanoparticle enters a biomolecular system¹. As a result of the Vroman effect², the most abundant proteins adsorb on the surface of the nanoparticle and are gradually exchanged with proteins with lower concentration but higher surface affinity. When nanoparticles enter living cells, they interact with largely different biomolecular environments from the moment of internalization until their exocytosis or until cell death, due to the complex endocytic pathways. In this study, J774, A549, HCT-116, and MCF-7 cell lines were incubated with 30 nm citrate-stabilized gold nanoparticles, and the protein corona of the particles was extracted and purified after the soft lysis of the cells. The corona constituents were separated with gel electrophoresis and excised segments of the gel were further analyzed by HPLC-ESI-Q-TOF mass spectrometry³. The cells were continuously in contact with gold nanoparticles during the whole incubation time, therefore intracellular gold nanoparticles are found in all stages of respective endocytic pathways. The different residence times of internalized particles in the whole cell culture, combined with the Vroman effect yield a sum corona composition that potentially reflects every biomolecular environment the nanoparticles can experience. The results indicate the gold nanoparticles’ interaction with the different proteins of fetal bovine serum found in the cell culture medium, the uptake mechanisms in different cell lines, and the processing of the gold nanoparticles. We found evidence of the cellular responses induced by the presence of gold nanoparticles that infer the specific fate of internalized gold nanoparticles and the cells themselves. Combining this method with in situ approaches, in particular vibrational spectroscopy or microscopy, can provide a comprehensive picture of the evolution of the protein corona in live cells.

¹C. D. Walkey and W. C. Chan, Chemical Society Reviews, 2012, 41, 2780-2799.
²L. Vroman, A. L. Adams, G. C. Fischer and P. C. Munoz, Blood, 1980, 55, 156-159.
³N. Fernandez-Iglesias and J. Bettmer, Nanoscale, 2015, 7, 14324-14331.



Keywords: Protein corona, gold nanoparticles, cell cultures





OPY-035

"Electrochemical, Spectroelectrochemical And Electrocatalytic Properties Of New Peripherally 2-Naphtol Substituted Metal-Free And Metallophthalocyanines Compounds"

Efe Baturhan Orman
Department of Chemistry, Marmara University, İstanbul, Turkey

“Phthalocyanine (Pc) derivatives involving conjugated π-electron systems usually display reversible electron transfer processes at modest potentials and superior physicochemical properties and thus, applicability in various advanced technological areas such as photodynamic therapy, photovoltaic cells, gas sensors, electrochromic materials, information storage and catalysis.
In this work, the electrochemical redox properties of new peripherally 2-naphtol substituted metal-free and metallophthalocyanines compounds were displayed on Pt in dimethylsulfoxide including tetrabutyl ammonium perchlorate as the supporting electrolyte by cyclic voltammetry, squarewave voltammetry, controlled-potential coulometry and in-situ electrocolorimetry supported in-situ spectroelectrochemistry. The compounds exhibited one-electron metal- and/or Pc ring-based reversible or quasi-reversible reduction and oxidation electron transfer processes. The interaction between these rich redox behaviors of the complexes and electrogenerated anionic and cationic species having distinct color and spectral changes indicates that their net electrocolorimetric changes suitable for electrochromic applications and high electrocatalytic activity for oxygen reduction reaction (ORR). Thus, electrocatalytic activity and methanol tolerance of the compounds dispersed on a high surface area carbon substrate, Vulcan XC-72 (VC) and Nafion (Nf), towards ORR were investigated and compared by surface cyclic voltammetry, rotating disk electrode, and rotating ring-disk electrode experiments in a medium similar to fuel-cell working conditions.
The Pc compounds involving redox-active Co(II) metal centers displayed high catalytic activity towards oxygen reduction, and thus suitability as possible cathode catalysts for fuel cell applications.”



Keywords: Electrochemistry, Insitu spectroelectrochemistry, Oxygen electrocatalysis


Cyclic voltammograms and in-situ UV-Vis spectral changes of cobalt(II) Phthalocyanine in DMSO/TBAP electrolyte system.







OPY-036

Local surface investigation of the electrochemical behaviour of an AISI 316Ti stainless austenitic steel, pre-heated and cold rolled

Fatah Hellal, Houria Kaddour
Department of Metallurgy, National Polytechnic School, Algiers, Algeria

In order to assess the surface behaviour of an AISI 316Ti austenitic stainless steel, that have been heat treated and cold rolled, several local analysis were carried out. Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and X-Ray Diffraction analyser (XRD) were used to bring morphological and microstructural information related to the steel. Scanning Vibrating Electrode Technique (SVET) have been used to give the electrochemical phases map, denoted by the formation of potential gradients. Correlation can be made between electrochemical behaviour and microstructural state of the stainless steel. The main results indicate that several phases take place inside an austenitic matrix, after high temperature treatment (up to 1100C). The cold rolling (up to 37%) leads to bulk plastic deformation. As consequence, at one part, martensite phase nucleates inside the austenitic matrix and, at the other part, slip bands and dislocations lattice develops in the bulk and leads to the emerging of steps at the surface. When preceded by heat treatment, only physical transformation occurs. The obtained heterogeneities act, after immersing the stainless steel in an acidic 0.5 M H2SO4 solution, as anodic areas, highlighted by the SVET technique.



Keywords: AISI 316Ti stainless steel, thermomechanical treatment, SVET technique


SEM and SVET characterization of AISI 316Ti stainless steel, at different states.

Here is the highlighting of the effect of modifying the AISI 316Ti austenitic stainless surface, by the mean of heat treatment followed by cold rolling. The morphology and the electrochemical behavior are object of interest.






OPY-037

Expanding the capabilities of wash-free, electrochemical DNA switches for the detection of diagnostic antibodies in authentic human samples

Claudio Parolo1, Di Kang2, Martin Kurnik2, Arben Merkoçi1, Kevin Plaxco Plaxco2
1Catalan Institute of Nanoscience and Nanotechnology
2Department of Chemistry and Biochemistry, University of California – Santa Barbara

A fast and precise diagnosis of infectious diseases -and thus the initiation of their treatment- is paramount to achieve a positive course of the disease. Here we present a novel wash-free, electrochemical sensor that measures the levels of specific antibodies directly at the point-of-care and during the few minutes timeframe of a typical doctor´s appointment.

Our platform, named E-DNA sensors, consists of a short, double-stranded nucleic acid attached by one end via a flexible linker to a gold electrode and modified on the other with a redox reporter (methylene blue) and an epitope/antigen (Fig.1-A). The binding of the specific antibody reduces the rate of electron transfer from the methylene blue to the electrode, generating a measurable change in the electrochemical signal, which we use to quantify the target concentration. E-DNA sensors are reagentless, single-step, and selective enough to deploy in whole blood serum, making them excellent candidates for point-of-care applications. In addition, the equilibration time constant of antibodies, generally in the order of few minutes, matches our “timeframe-goal”.

We demonstrated that E-DNA sensors achieve the same clinical sensitivity and specificity as those of ELISAs and lateral flow immunoassays. In particular we first showed that we can include as recognition elements of our sensing platform not only linear epitopes but also full-size antigens (<70 kDa, Fig.1-B). Second, taking advantage of this modularity, we designed five sensors employing different epitopes from the HIV-antigen gp41 and one using the full p24 antigen. Third, after confirming the immunogenicity of each epitope/antigen using classical methods, we simultaneously detected multiple HIV-specific antibodies directly in human samples. Thanks to the “multiplexability” of our platform we not only discriminated HIV-positive from healthy patients, but also we differentiated early-infected from late-infected individuals (Fig.1-D).

The E-DNA platform appears a versatile, clinically sensitive and specific method for the rapid, single-step detection of antibodies at the point-of-care.



Keywords: Electrochemical sensors, Infectious diseases, Antibody detection


Figure 1

Figure 1. A) Cartoon of the E-DNA electrochemical antibody sensor. Antibody binding to the appended epitope reduces the electron transfer efficiency between the redox reporter and the electrode surface, inducing a measurable change in the electrochemical signal. B) Impact of the antigen size on the binding-induced signal change. Recognition elements up to 70 kDa produce a measurable signal change, making possible the use of some full-size antigens, besides short linear epitopes. C) Continuous measurement of HIV-positive and negative serum using E-DNA sensors. D) Discirimination of healthy, early-infected and late-infected HIV-positive patients using E-DNA sensors.






OPY-038

An insight into the detection of Group A Streptococcus pyogenes with SERS-based assays

Merve ERYILMAZ1, Esra SOYKUT2, Demet ÇETİN3, Ismail Hakkı BOYACI4, Zekiye SULUDERE5, Uğur TAMER1
1Department of Analytical Chemistry, Gazi University, Faculty of Pharmacy, 06330, Ankara, Turkey.
2Division of Food Quality Control and Analysis, Yeniçağa Yaşar Çelik Vocational School, Abant Izzet Baysal University, 14650, Bolu, Turkey.
3Department of Mathematics and Science Education, Gazi Faculty of Education, Gazi University, 06500 Ankara, Turkey.
4Department of Food Engineering, Faculty of Engineering, Hacettepe University, 06800, Ankara, Turkey
5Department of Biology, Faculty of Science, Gazi University, 06500, Ankara, Turkey.

Beta-hemolytic bacteria, Group A Streptococcus pyogenes (GAS), is the main cause of acute pharyngitis which is accounting for 40% of symptoms in children and 10% of symptoms in adults. The patients with acute pharyngitis are generally diagnosed in the throat and this test may be either a plate counting or a rapid antigen detection tests. However, the conventional analysis of GAS, gold standard, takes 48 hours and the related rapid tests are lack of accuracy and sensitivity. To overcome mentioned problems, the efficiency of swab sampling, which it is a must in the GAS detection, was discussed first with the proposed surface-enhanced Raman spectroscopy (SERS)-based batch assay and each step was controlled with the plate-counting method. This batch analysis was the fundamental for the proposed study, since all detections of GAS start with the swab sampling of a throat. Secondly, SERS-based lateral flow immunoassay (LFIA) test strips were constructed to enable sensitive and accurate detection of GAS. Thus, a linear correlation was found with R² of 0.9926 and the LOD was calculated as 0.2 CFU/mL which could be counted as one cell and GAS was quantified with SERS-based paper test strips up to 100 CFU/ml level of bacteria for the first time without any interference. In addition, more than the size or shape of bacteria there was a difference in the group of gram-staining which is based on the cell wall constituents of pathogen bacteria, and this effected the sampling of the bacteria. Thus, developed method enabled the rapid and sensitive detection of GAS without an extra step of result confirmation.



Keywords: Group A Streptococcus, SERS, lateral flow immunoassay


Fig. 2. A) Images of LFIA strips and the different test line (T) colors against increasing SP concentration in the range of 0-107 CFU/mL. B) Linear calibration curve for obtained from test lines depending on SP concentration against SERS intensity.



Fig.1. Schematic illustration of the SERS-based batch analysis of Group A Streptococcus pyogenes (SP).







OPY-039

Molecular recognition of p53, CEA, CA19-9 in whole blood

Ruxandra Maria Ilie Mihai1, Raluca Ioana Stefan Van Staden1, Florina Pogacean2, Maria Coros2, Stela Pruneanu2
1Laboratory of Electrochemistry and PATLAB, National Institute of Research for Electrochemistry and Condensed Matter, 202 Splaiul Independentei Str., 060021, Bucharest-6, Romania
2National Institute for Research and Development of Isotopic and Molecular Technologies, Donat Street, No. 67-103, 400293, Cluj-Napoca, Romania

Gastric cancer is right now a standout amongst the most widely recognized gastrointestinal malignancies. P53, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 are utilized as markers of gastrointestinal cancer. CA 19-9 and CEA are antigens related with a large portion of epithelial started malignant growths, including gastrointestinal diseases. Serum levels of CEA and CA 19-9 are expanded in premalignant lesions and beginning stages of malignant growth.

Special graphene materials modified with different heteroatoms were synthesized for the molecular recognition of gastric cancer biomarkers. Stochastic sensors are promising tools for molecular recognition of biomarkers at a very early stage of the disease, due to their capacity of recognizing the analytes (qualitative analysis) in complex matrices, and also to reliable quantify them. Seven stochastic microsensors based on different graphene powders modified with different electroactive materials such as protoporphyrin IX (PIX) and Chitosan I, were proposed for the assay of p53, CEA and CA19-9 in whole blood samples. Stochastic mode was used for the qualitative and quantitative assessment of p53, CEA and CA19-9. Characterization of the stochastic sensors as well as their validation will be shown. The proposed stochastic sensors can be successfully used for the screening of whole blood and tumor tissues for p53, CEA and CA19-9. The main feature is utilization of the stochastic sensors for screening tests of asymptomatic patients for early diagnosis of gastric cancer.

Acknowledgements
This work was supported by a grant of the Romanian National Authority for Scientific Research, CNCS– UEFISCDI, project number PN-III-P4-ID-PCCF-2016-0006.



Keywords: gastric cancer, stochastic sensor, bioanalysis





OPY-040

A Biosensor Study Based on Polymeric Nanomaterial as Biologically Active Layer for Detection of MUC1 in Cancer Diagnosis/Prognosis and Follow-Up

Fulden Ulucan, Sinan Akgöl
Department of Biochemistry, Faculty of Science, Ege University, İzmir, Turkey

Musin 1 (MUC1) is a glycosylated transmembrane protein which has an essential role in forming protective mucous barriers on epithelial surfaces. It is expressed in healthy epithelial cells is limited to the apical surface. Cancer cells are expressed MUC1 on all surfaces due to loss of polarity 100-fold more than healthy cells. MUC1 is overexpressed in all cancer types during the progression of the disease, angiogenesis, and metastasis. The use of MUC1 as a potential biomarker in cancer enables the possibility of a simple serological test for cancer prognosis/diagnosis, follow-up, and treatment. Over the past three decades, different types of MUC1-based vaccines have been developed as a part of cancer immunotherapy both in preclinical experimentation and clinical trials.

Cancer is increasingly a global health issue. Each year, millions of people are diagnosed with cancer around the world, and more than half of the patients eventually die from it. Therefore, its early diagnosis is the key to easy, inexpensive and effective treatment. The market for biomedical diagnostic is expected to grow $43 billion by 2029 due to ageing, growing global population and unhealthy lifestyle. Cancer diagnosis due to biosensors correspond to 10% of biomedical diagnostic market. In the literature, there are several studies in terms of biosensors for cancer diagnosis based on nanomaterials because of their features as high surface area, sensitivity and easy to produce.

Our research is based on developing a polymeric nanomaterial for MUC1 to be used as a biologically active layer on the sensor surface. A nano-sized polymer is functionalized due to lectin affinity technique for MUC1 detection. The nanopolymer was synthesized using the mini-emulsion polymerization method. Advanced characterization studies of the nanopolymer were conducted by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), atomic force microscopy (AFM), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), zeta size and potential analysis, conductivity measurements, particle specific surface area calculations. The nanomaterial has approximately 75-80 nm size, 2955,057 m²/g specific surface area, -34,76 mV surface potential at distilled water. The surface of the electrodes was characterized by ellipsometer and contact angle measurements. Surface thickness of the electrode and angle of contact were determined as 3141.20 Angström and 38.79o respectively. The working conditions of the electrochemical nanobiosensor system will be optimized using PalmSens. After analytical measurement characteristics have been determined due to DPV and CV measurements, validation studies will be done with statistical measurements. Real sample measurements will be done with artificial blood and urine.

The developed electrochemical biosensor’s potential to be used in the form of medical diagnostic kit will be elucidated due to comparison with commercial kits for detection of MUC1 in the market. Miniaturization studies of the developed electrochemical biosensor may lead to commercialization for a diagnostic kit which has a potential of sensitive, reliable and quick measurement for early diagnosis, prognosis and follow up of cancer disease.



Keywords: MUC1, cancer diagnose kit, polymeric nanomaterial





OPY-041

A Surface-enhanced Raman Scattering- Thin Layer Chromatography Approach for Early Cancer Detection from Blood Samples

Hulya Yilmaz1, Ertug Avci1, Stephen Palani2, Fehmi Civitci2, Xiaolin Nan2, Buruce Branchaud2, Sadik Esener2, Mustafa Culha1
1Yeditepe University, Department of Genetics and Bioengineering, 34755, Istanbul, Turkey
2Oregon Health and Science University, Knight Cancer Institute, Cancer Early Detection Advanced Research (CEDAR), Portland, Oregon, USA

Blood contains numerous cancer-related molecular species including tumor-educated platelets (TEP), circulating tumor cells (CTCs), cell-free tumor RNA (cRNA), exosomes and circulating cell-free tumor DNA (cDNA). The assessment of these biomarkers is considered as an effective strategy for cancer screening and early diagnosis [1]. With its extremely high sensitivity, Surface-enhanced Raman Scattering (SERS) is employed for the solution of numerous challenging problems in a variety of fields including biotechnology and medicine [2]. In our previous studies, we demonstrated that SERS could successfully differentiate cancerous tissues, cells and blood from their controls [3,4]. Thin layer chromatography (TLC) is a simple, fast and low-cost technique to separate components of a molecular mixture and it was previously coupled to SERS and mass spectroscopy [5,6]. After the separation step, the spots on the TLC place can be analyzed with a spectroscopic technique such as SERS [7,8,9]. In this study, blood metabolites contributing a SERS spectrum of blood plasma or serum is investigated after a crude separation step on a TLC plate. An 830 nm of laser is used for SERS experiments. The findings of the study suggest that the bands dominating a SERS spectrum of plasma or serum originate from small molecular metabolites. Upon successful identification of these molecules in relation to cancer development in a tissue, a highly sensitive SERS based detection system be devised for clinical use.

References
1) Santarpia M., Karachaliou N., González-Cao M., et al. Feasibility of cell-free circulating tumor DNA testing for lung cancer. Biomark Med 2016; 10: 417-30.
2) Culha M., Cullum B., Lavrik N, and Klutse C. K. Surface-Enhanced Raman Scattering as an Emerging Characterization and Detection Technique. Journal of Nanotechnology. 2012, 15.
3) Mert S., Culha M. Surface-Enhanced Raman Scattering-Based Detection of Cancerous Renal Cells. Applıed Spectroscopy. 2014, 68, 6.
4) Kuku G., Sarıcam M., Mert S., Culha M. Surface-enhanced Raman scattering from living cells: From differentiating healthy and cancerous cell to cytotoxicity assessment. 2015, 9487,2.
5) Sherma, J. Planar Chromatography. Analytical Chemistry, 2000, 72, 9R−25R.
6) Sherma, J. Planar Chromatography, J. Anal. Chem. 2010, 82, 4895−4910.
7) Zong-Mian Z., Jing-Fu Liu, Rui L., Jie-Fang Sun, and Guo-Hua W. Thin Layer Chromatography Coupled with Surface-Enhanced Raman Scattering as a Facile Method for On-Site Quantitative Monitoring of Chemical Reactions. Analytical Chemistry. 2014, 86, 7286−7292.
8) Freye, C. E., Crane, N. A., Kirchner, T. B., Sepaniak, M. J., Anal. Chem. 2013, 85, 3991–3998.
9) Connaster, R. M., Riddle, L. A., Sepaniak, M. J., J. Sep. Sci. 2004, 27, 1545–1550.
10) Fawzi A. E., Omayma A. A., Eman I. E., Essam F. K., Sameh E. Y. High-performance thin-layer chromatographic methods for the determination of febuxostat and febuxostat/diclofenac combination in human plasma. Journal of Chromatography B. 2018, 1086, 89–96.



Keywords: Early cancer detection, TLC-SERS, biomarker


Figure 1. Schematic representation of TLC-SERS based detection







OPY-042

Microfabricated gold array electrodes modified by nanomaterials for highly sensitive electrochemical applications

Vuslat Buk, Martyn E. Pemble
Tyndall National Institute, School of Chemistry, University College Cork, Lee Maltings Complex, Dyke Parade, Cork, IRELAND

We report the lithographic fabrication of several band and disk array electrodes of different dimensions to be used as biosensor components for three different approaches to detect glucose. These model systems were studied in detail in order to demonstrate the unique characteristics of micro array electrodes as well as the nanomaterials selected for the construction of highly sensitive and selective electrochemical biosensors.
In the first study, we used a carbon quantum dot (CQDs) and gold nanoparticle (AuNPs) nano-hybrid system for glucose oxidase immobilization onto micro disk array electrodes. Comparing the response of the developed microbiosensor with that of the planar counterparts we found that the microbiosensor exhibited a superior sensitivity of 626.06 μA mM⁻¹ cm⁻² (Buk & Pemble, 2019) towards glucose, some 13 times higher than the response from the planar electrode, 47.24 μA mM⁻¹ cm⁻². Fig.1 represents a schematic image of the high surface area biosensor developed (Buk, Pemble & Twomey, 2019). The second approach selected was aimed at demonstrating the enzyme-free detection of glucose in the presence of copper nanocrystal deposits as a 3D foam structure (Buk, Walcarius & Pemble, submitted). For this purpose, electrodes were prepared by electrodeposition of copper onto gold surfaces at over negative potentials in an acidic environment. SEM images show highly symmetric and homogenous deposits of copper over the band and disk array electrodes (Fig. 2). The resulting Cu-foam micro array electrodes showed a very strong electrocatalytic activity towards glucose and exhibited outstanding sensitivities with wide linear ranges up to 20.55 mM. The final approach for glucose detection was a bi-enzymatic system. In this study nanostructured gold (Au) was electrodeposited onto band array electrodes to form an Au foam with high surface area. Then, chitosan and multi walled carbon nanotubes were electrodeposited to cover the gold nanostructures (Fig. 3a) as a thin polymeric layer. Finally a glucose oxidase and horseradish peroxidase enzyme mixture was immobilized on the surface. The bi-enzymatic biosensor developed showed excellent analytical performance with a sensitivity of 261.8 μA mM⁻¹ cm⁻² and high reprodubility (RSD, 3.30%, n=7), Fig.3b.
To summarize, we demonstrate the use and importance of several emerging nanomaterials combined with microfabricated gold array electrodes as miniaturized, highly sensitive electrochemical sensing platforms.

The authors appreciate the financial support from the Department of Agriculture, Food and the Marine, 14F883, Ireland.

References:

Buk, V., & Pemble, M. E. (2019). A highly sensitive glucose biosensor based on a micro disk array electrode design modified with carbon quantum dots and gold nanoparticles, Electrochimica Acta, 298, 97-105. doi: 10.1016/j.electacta.2018.12.068

Buk, V., Pemble, M. E., & Twomey, K. (2019). Fabrication and evaluation of a carbon quantum dot/gold nanoparticle nanohybrid material integrated onto planar micro gold electrodes for potential bioelectrochemical sensing applications, Electrochimica Acta, 293, 307-317. doi: 10.1016/j.electacta.2018.10.038

Buk, V., Walcarius, A., & Pemble, M. E. Non-enzymatic detection of glucose using Cu foam nanostructures deposited electrochemically onto band array electrodes, manuscript submitted



Keywords: micro(array)electrodes, electrochemical biosensors, nanomaterials


Figure 1

Schematic image of the CQDs/AuNPs-GOx biosensor


Figure 2

SEM images of copper foam deposited band and disk array electrodes


Figure 3

SEM image of gold foam wall covered by thin film of chitosan embedded multiwalled carbon nanotubes layer (a), reproducibility of the developed biosensor, n=7 (b)






OPY-043

An all inkjet-printed glucose sensor on paper

Eloise Bihar1, Shofarul Wustoni2, Anna Maria Pappa4, Sahika Inal2, Derya Baran3, Khaled Nabil Salama1
1Division of Computer, Electrical and Mathematical Sciences and Engineering, Advanced Membranes and Porous Materials Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
2Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia;
3Division of Physical Science and Engineering, KAUST Solar Center, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
4Department of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive, Cambridge, UK

Inexpensive and easy-to-use diagnostic tools for fast health screening are imperative, especially in the developing world, where portability and affordability are a necessity. Continuous monitoring of metabolite levels (such as glucose, lactate, cholesterol etc) can provide useful information regarding key metabolic activities of the body and detect associated irregularities such as in the case of diabetes, a worldwide chronic disease. Inconvenience and discomfort of daily glucose monitoring relying on painful finger pricking to draw blood have created a global need to develop noninvasive, accurate and low cost glucose assays.
In this work, we use the commercially available biocompatible conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate and inkjet printing toward the realization of high performance metabolite biosensors using enzymatic electrochemical detection (Figure 1). We demonstrate the sensor performance on measuring metabolite concentrations in alternative-to-blood body fluids, such as saliva or sweat, with sensitivity range that matches the concentrations of the bespoke biological fluids. The device exhibits a linear response to glucose within the range relevant to the glucose concentrations of saliva (from 28 μM to 0.85 mM). We show that one month after its fabrication, the sensor maintains its function with only minor performance loss (80 ± 3%).
This all-polymer “smart multisensor” fully printed on top of commercial paper, with its ease of fabrication, accuracy, sensitivity and compatibility with easy-to-obtain biofluids advances on the next generation low cost, disposable, noninvasive, multiparameter sensing point-of-care diagnostics.



Keywords: Biosensor, inkjet-printing, paper


Figure 1.

Photograph of a printed sensor on paper






OPY-044

Low-cost paper-origami device for rapid microbial analysis in low resource settings

Zhugen Yang1, Yuwei Pan2, Kang Mao2, Julien Reboud2, Jonathan Cooper2
1Cranfield University
2University of Glasgow

Microbial detection is of significant importance for both biomedical diagnostics (such as infectious disease) and environmental monitoring (e.g. microbial contamination in drinking water). This has traditionally been performed by culturing and typing the pathogens, however, these procedures are often take several hours or days. This has equally poor outcomes, both for industry and for consumers (with associated poor healthcare outcomes). There is, therefore, an urgent need to develop rapid and sensitive platforms that can provide rapid analysis of microbial both for biomedical diagnosis or monitoring water quality. Molecular approaches (such as polymerase chain reaction (PCR) detecting genetic markers) will deliver faster turn-around times (< 1 hour) than culture-based methods, but currently require centralised facilities and skilled personnel to perform the assays and interpret results.

Here we report on a low-cost, deployable paper-based biosensor devices for rapid analysis of microbes. Using a paper-microfluidic sensor with isothermal amplification technologies, we have demonstrated rapid, sensitive and easy-to-use sample-to-answer testing devices for rapid infectious disease of bovine, which was also field tested in India. Pathogen DNA from one viral pathogen, Bovine Herpes virus-1 (BoHV-1) and two bacteria (Brucella and Leptospira) was extracted, amplified (using loop-mediated isothermal amplification, LAMP) and detected fluorescently, enabling <1 pg (~ from 115 to 274 copies per reaction) of target genomic DNA to be measured. Data was collected as a fluorescence signal either visually, using a low-cost hand-held torch, or digitally with a mobile-phone camera (Figure 1). Limits of detection and sensitivities of the paper-origami device for the three pathogens were also evaluated using pathogen-inoculated semen samples and were as few as 50 Leptospira organisms, 50 CFU Brucella and 1 TCID50. BoHV-1, per reaction. Semen samples from elite bulls at a germplasm centre were tested in double-blind tests, as a demonstrator for a low cost, user-friendly point-of-care sensing platform, for in-the-field testing in resource-limited regions. The sensors showed excellent levels of sensitivity and specificity, and for the first of time demonstrated the application of paper-origami devices for the diagnosis multiple infectious diseases from semen samples. We also show this device for the rapid test of microbial contaminations in drinking water, with a flexible sampling enrichment strategy with magnetic beads. We aim to develop this low-cost device for the rapid test of microbial contamination in low and middle income countries to address global water water contamination issues.

Reference
[1] Yang, Z., et al. (2018). "Rapid Veterinary Diagnosis of Bovine Reproductive Infectious Diseases from Semen Using Paper-Origami DNA Microfluidics." Acs Sensors 3(2): 403-409.

[2] Yang, Z., et al. (2017). "Monitoring Genetic Population Biomarkers for Wastewater-Based Epidemiology." Ana Chem 89: 9941-9945.



Keywords: Paper-microfluidic, microbial analysis, infectious disease





OPY-045

Advanced fabrication of miRNA based electrochemical nanobiosensor for diagnosis of breast cancer

Cansu Ilke Kuru, Sinan Akgöl
Department of Biochemistry, Ege University, İzmir, Turkey

Breast cancer corresponds to 22.7% of total cases, with approximately 1.15 million new cases in women, among 23 different types of cancer. Its early diagnosis is the key to easy, inexpensive and effective treatment. Therefore, studies have been accelerated in order to determine biomarkers that will allow the diagnosis of breast cancer and even to identify the cancer, and to develop methods for determination of these markers. Various studies in breast cancer have supported expression of miRNA-155 at a different level than at different stages of the disease. The use of miR-155 as a potential biomarker in breast cancer enables the possibility of a simple serological test for breast cancer prognosis/diagnosis, follow-up and treatment.
In this study, synthesized nano-sized nanopolymers to be used as biologically active layer on the sensor surface with thiol affinity technique based on miRNA detection. The nanopolymers containing different functional groups for use as bioactive layers in nanobiosensor system were synthesized using the mini-emulsion polymerization method. Advanced characterization studies of nanopolymers to be obtained and integrated on electrochemical biosensor electrodes with SEM, AFM, FTIR, XPS, TGA, ellipsometer, contact angle measurements, zeta size and potential analysis, conductivity measurements, particle specific surface area calculations were carried out. The working conditions of the electrochemical nanobiosensor system will be optimized. After analytical measurement characteristics have been determined, validation studies will be done. The real sample analysis will be carried out.
As the final part of the study, the developed electrochemical biosensor’s potential to be used in the form of medical diagnostic kit will be elucidated due to comparison with commercial kits for detection of miR-155 in the market. With these new generation nanobiosensor, the aim is to develop a product with a potential sensitive, reliable and quick measurement for early diagnosis, prognosis and follow up of breast cancer.



Keywords: Electrochemical nanobiosensor, breast cancer, miR-155





OPY-046

Voltammetric Determination of Levofloxacin at Poly(L-Arginine) Film Electrode

Çağrı Ceylan Koçak
Bergama Vocational School, Dokuz Eylül University, İzmir, Turkey

Levofloxacin (LEV), is a member of fluoroquinolone antibiotics that has activity to both Gram-negative and Gram-positive bacteria (Steuber et al., 2018). It has an anti-microbial activity and used for the treatment of urinary, respiratory and skin infections such as dysentery and tuberculosis (Aragon-Martinez et al., 2017). Therefore it is important to determine levofloxacin in human fluids and pharmaceutical tablets.
Conductive polymer films have gained great interest due to their conductivity, porous structure and stability. They have wide application field such as sensing and pharmaceutical industry (kuskur et al., 2017; Ozcan et al., 2017). L-arginine is an essential amino acid and found naturally in foods such as nuts, wheat flour, and seeds (Szefel et al., 2019). It is also used as an electrode modifier recent years. Arginine has -NH2 and -COOH groups in its structure that they facilitate the polymerization. Polymerized arginine film electrodes were employed for the determination of various compounds (Ma and Sun, 2007; Qiao et al., 2015).
This study describes the electrochemical polymerization of L-arginine on glassy carbon electrode via cyclic voltammetry technique. Resulting modified electrode was characterized with electrochemical impedance spectroscopy and scanning electron microscopy. Poly(L-arginine) film electrode was employed for investigation of levofloxacin behavior in pH 6 phosphate buffer solution. In order to improve the analytical signal of levofloxacin, supporting electrolyte pH, cycle number of polymerization and concentration of monomer was optimized. Linear sweep voltammetry and amperometry was studied under optimized conditions and levofloxacin was determined with a good linearity in a wide range. The proposed electrode was stand out with its low detection limit and high stability as a levofloxacin sensor. Interference effect of other fluoroquinolone substances and ionic compounds were also studied and each substance has no significant effect on 5 µM LEV (RSD ≤ %5). The determination of LEV was accomplished successfully with the poly(L-arginine) film electrode in synthetic urine and LEV tablets. In brief, proposed conductive polymer film electrode is a good alternative for levofloxacin determination with high sensitivity, stability and good selectivity.

References

Aragon-Martinez O.H., Isiordia-Espinoza M.A., Galicia O., Romo S.A., Gómez A., Romano-Moreno S., Martinez-Morales F., Clinical Biochemistry, 50 (2017) 73–79.
Kuskur C.M., Swamy B.E.K., Jayadevappa H., J. Electroanal. Chem. 804 (2017) 99–106.
Ma W., Sun D.-M., Chinese Journal of Analytical Chemistry, 35(1) (2007) 66-70.
Ozcan A., Ilkbas S., Ozcan A.A., Talanta 165 (2017) 489–495.
Qiao W., Wang L., Li H., Li G., Li J., Ye B., Talanta. 144 (2015) 726–733.
Steuber H., Williams D., Rech M.A., The American Journal of Emergency Medicine, 36(8) (2018) 1528.e1-1528.e2.
Szefel J., Danielak A., Kruszewski W.J., Advances in Medical Sciences 64 (2019) 104–110.



Keywords: Levofloxacin, poly (L-Arginine), Voltammetry





OPY-047

Design of an electrochemical biosensor system for Suppression of Tumorigenicity 2 detection based on fullerene C60 modified disposable Graphite Paper electrode

Burçak Demirbakan, Mustafa Kemal Sezgintürk
Department of Bioengineering, Çanakkale Onsekiz Mart University, Çanakkale, Turkey

In this work, we designed an ultrasensitive and an electrochemical immunosensor based on fullerene C60 modified disposable graphite paper (GP) electrode for determination of Suppression of Tumorigenicity 2 (ST2) in human serum. ST2 immunosensor was carried out by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV). Crucial parameters and analytical characteristics of the proposed immunosensor were optimized. The ST2 electrochemical immunosensor had excellent repeatability, reproducibility and a wide detection range (from 0.1 fg/mL to 100 fg/mL). The proposed immunosensor had also low limit of detection (LOD) and limit of quantification (LOQ) values as 0.124 fg/mL and 0.414 fg/mL, respectively. The ST2 biosensor system was applied in human serum for applicability in clinical practice.



Keywords: Suppression of Tumorigenicity 2, electrochemical impedance spectroscopy, cyclic voltammetry





OPY-048

Label-free electrochemical detection of microRNA by graphene oxide modified disposable electrodes

Ece Eksin1, Arzum Erdem Gursan2
1Biotechnology Department, Graduate School of Natural and Applied Sciences, Ege University, Bornova, 35100, Izmir, Turkey
2Analytical Chemistry Department, Faculty of Pharmacy, Ege University, Bornova, 35100, Izmir, Turkey

Graphene oxide (GO) modified pencil graphite electrodes (PGEs) were utilized for electrochemical detection of miRNA-34a. GO modified PGEs were provided a convenient surface for immobilization of immobilization of DNA probe. Then, the complementary target RNA sequence (miRNA-34a) was recognized by DNA probe immobilized GO-PGEs via differential pulse voltammetry (DPV) technique. The electrochemical and microscopic characterization of the GO-PGEs were performed by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM), respectively. The optimization studies were then performed and the selectivity of our assay was tested in the presence of non-complementary miRNA sequence.



Keywords: microRNA, electrochemical biosensor, graphene oxide


Table 1
GO concentration (µg/mL)The average Rct value (Ohm)
0105 ± 9.83
508 ± 11.31
10058 ± 7.07
20035 ± 2.82
The average Rct values measured by EIS measurements, before and after surface modification of GO in different concentrations (n=2).

Table 2
miRNA-34a target concentration (µg/mL)The average guanine oxidation signal (nA)
10247.75 ± 34.51
20464 ± 27.17
30613.40 ± 71.92
40909 ± 106.07
50838.40 ± 130.18
The average guanine oxidation signals measured after hybridization of 20 µg/mL miRNA-34a probe and miRNA-34a target in different concentrations varying from 10 to 50 µg/mL (n=3).





OPY-049

Propolis and Its Active Component, Caffeic Acid Phenethyl Ester (CAPE): Correlation Between CAPE Contents and TNF-α Enzyme Inhibitory Activities

Zeynep Kalaycıoğlu1, Çisil Alim1, Sevgi Kolaylı2, F. Bedia Erim1
1Department of Chemistry, Istanbul Technical University, Istanbul, Turkey
2Department of Chemistry, Karadeniz Technical University, Trabzon, Turkey

Propolis is a resinous product accumulated by the honey-bees from plants. It has several applications in the treatment of various diseases due to its anti-inflammatory, antioxidant, antibacterial, and anticancer activities. Caffeic acid phenethyl ester (CAPE) is natural bioactive compound of propolis. Since CAPE has a great deal of pharmacological properties, the bioacitivities of propolis can be attributed to the presence of CAPE. The chemical composition and the amounts of the compounds in propolis varies depending on the flora of collecting area. Thus, it is difficult to come to a general conclusion about the health benefits of propolis.

In this study, a micellar electrokinetic capillary chromatography (MEKC) technique was developed for the determination of CAPE. The working electrolyte composition was selected as 40 mM N-cyclohexyl-3-aminopropanesulfonic acid (CAPS), 50 mM sodium dodecyl sulfate (SDS) and 10 mM 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD) at pH 10.4. In this condition, the method was well-validated. The limit of detection (LOD) was calculated as 1.48 µg/mL and the limit of quantification (LOQ) was 4.93 µg/mL. The developed MEKC technique was applied for two propolis samples collected from Sivas and Zonguldak provinces from Turkey. Commercial propolis throat spray samples were also evaluated. CAPE amounts of the commercial propolis spray samples (n=4) were between in the range of 16.88 – 80.45 mg CAPE/100 mL. CAPE levels of Sivas and Zonguldak propolis samples were found to be 330.8 and 441.7 mg CAPE/100g propolis, respectively. Moreover, anti-inflammatory activities of propolis samples were measured based on the in-vitro inhibitory activity of tumor necrosis factor-α (TNF-α) enzyme. Inhibition values of commercial propolis sprays were found between 55.35% and 83.92%. The propolis samples collected from Sivas and Zonguldak inhibited TNF-α by 68.75% and 66.07%, respectively.

Finally, the correlation between the amount of CAPE in the samples and the anti-inflammatory activities of the samples was investigated and found to be 0.944. This high correlation indicates that CAPE has an important role on the anti-inflammatory effect of propolis. In this study, Anatolian propolis was firstly analyzed with regards to their CAPE amounts and anti-inflammatory activities.



Keywords: CAPE, propolis, micellar elektrokinetic capillary chromatography





OPY-050

Preparation of hydrothermal Carbon from indigenous waste and its applications in water purification

Abdullah Memon1, Najma Memon2
1National Institute of Oceanography, Ministry of Science and Technology Government of Pakistan
2National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan

Carbon based materials prepared by hydrothermal process is worldwide known, due to less consumption of energy and variety of applications. In this study, we have utilized waste of Jujube Ziziphus Mauritiana L. varkheerol for preparation of activated carbon through hydrothermal process. Carbonization was carried out at 180 ○C for five hours and percent yield of 18.8 was obtained. HTCs were characterized by SEM, XRD and BET for surface characterization and FT-IR was used for identification of functional groups. These techniques reveal that material is amorphous and porous in nature with –OH, -CO functionalities. HTCs prepared was also compared with commercial activated carbon by moisture content, ash content, acid soluble iron via atomic absorption. Removal of cadmium by prepared HTCs were optimized using Response Surface Methodology (RSM). Capacity values obtained at optimum parameters were 48.90 mg/g. Equilibrium data followed Langmuir Isotherm with r value of 0.94 with Langmuir capacity of 83.33 mg/g. DR Isotherm suggested that the adsorption was purely based on ion exchange mechanism with energy of adsorption 15.81 KJ/mol. Removal of metal ion were tested from real water systems and Removal of 96.2 % was obtained.



Keywords: Hydrothermal Carbonization, Removal Optimization, Waste materials





OPY-051

High-precision 143Nd/144Nd ratios of trace Nd by thermal ionization mass spectrometry for nuclear forensics

Xuepeng Shao1, Wenting Bu1, Kaiming Long1, Lei Tang1, Xuemei Liu1, Heng Yan2, Fanhua Hao1
1Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang, China
2CAS Key Laboratory of Soft Matter Chemistry, University of Science and Technology of China, Hefei, China

The phenomenon of nuclear smuggling and illicit trafficking of nuclear material has led to the development of a new branch of science—nuclear forensics. The key issue of nuclear forensics is the identification of the origin and history of the seized or found nuclear materials. 143Nd/144Nd isotope ratio, which has been widely applied in geochemistry and geochronology, is recently recognized as a potential signature for tracing the origin of nuclear-related materials because Nd isotopic composition is less prone to be affected by metallurgical processes. In order to utilize the ideal isotopic tracer, 143Nd/144Nd isotope ratio measurement with precision better than 50 ppm is required.

Neodymium isotope analysis as Nd+ ions is more favored than as NdO+ ions due to less potential isobaric interferences and no need for complicated oxygen isotope corrections. However, the poor sensitivity and inadequate reproducibility seriously hinder the application of Nd+ ion technique. Recently, we initially developed a new analytical method by thermal ionization mass spectrometry (TIMS) for precise 143Nd/144Nd ratio analysis as Nd+ ions with film porous ion emitters (FPIEs), combined with a simplified Nd chemical separation procedure. The Nd+ ion yields of the method were one order of magnitude higher than that of traditional Nd+ ion analysis method, and is even comparable with those of NdO+ ion analysis method reported previously. The possible mechanisms of FPIEs in improving sample utilization and reproducibility of Nd isotope ratio analysis were discussed as well. Repeated measurements of 1 ng reference material JNdi-1 yielded a 143Nd/144Nd value of 0.512113 ± 33 (2SD, n=9). The achieved external precisions fulfilled the requirements for applications in nuclear forensics. Several international rock reference materials with a wide range of matrix composition and uranium ore samples were also analyzed to further verify the accuracy and reproducibility of our method. The newly-developed TIMS approach is much less laborious and time-consuming, and we believe that this method is not merely of particular value for nuclear forensic purposes, but also expands the applications in geochemistry, geochronology and environmental sciences.



Keywords: Neodymium isotope, Thermal ionization mass spectrometry, Nuclear forensics





OPY-052

Development and validation of a bioanalytical assay to detect biomarkers for antidepressant use in influent wastewater

Tim Boogaerts, Maarten Degreef, Adrian Covaci, Alexander Ln Van Nuijs
Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium

Wastewater-based epidemiology applies the analysis of human metabolic excretion products of xenobiotics in wastewater to estimate the community-wide use of these compounds. The low ng/L range of concentrations of biomarkers present in a complex matrix such as wastewater pose a clear bioanalytical challenge related to sample preparation and detection/quantification. Therefore, sensitive bioanalytical methods need to be developed, optimised and validated for the detection and analysis of a broad range of selected biomarkers at trace concentrations in influent wastewater.

We developed and validated an analytical approach based on solid-phase extraction and liquid chromatography coupled to tandem mass spectrometry for the simultaneous detection and quantification of 27 antidepressants and their metabolites in influent wastewater. For most compounds, Oasis® HLB cartridges were used for sample preparation. Oasis® MCX cartridges were used for extraction of normirtazapine, moclobemide, sertraline, and melitracen in particular. The Kinetex XBC18 column with a gradient elution resulted in appropriate separation for the analytes under investigation. Validation was done according to the European Medicines Agency guidelines on bioanalytical method validation and the performance criteria met the requirements. For these analytes, the lower limit of quantification (LLOQ) ranged between 1 and 25 ng/L. Furthermore, all targeted biomarkers showed high in-sample stability during 24 h, with the exception of mianserin. In addition, all compounds under investigation showed high on cartridge-stability (< 20% transformation) after 1.5 months of storage at −20 °C in an air-tight freezer bag. For five compounds, the deuterated analogue used as internal standard (IS) did not correct for matrix effects and highlights the need of a thorough assessment of matrix effects during method validation even if deuterated analogues are used as IS. The validated assay was applied to influent wastewater samples collected from four wastewater treatment plants in Belgium. Among these four locations, a total of 18 out of 27 biomarkers for antidepressant use were present in the samples in concentrations above the LLOQ. The results could be used to look at spatial and temporal trends in antidepressant use.



Keywords: Method Development and Validation, Wastewater analysis, Antidepressants


Graphical Abstract

This file includes the graphical abstract.






OPY-053

Graphene oxide and Vanadium oxide devices as capacitive sensors for soil moisture: its temperature effects and measurement study

Sandeep G Surya1, Saravanan Yuvaraja1, Khaled N Salama1, Vinay S Palaparthy2
1Sensors Lab, Advanced Membranes & Porous Materials Center (AMPMC), CEMSE, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
2VLSI and Embedded Systems Group, Dhirubai Ambani Information Institutute of Information and Communication Technology, India

Recently, the strategy to use oxide materials have become popular in humidity and agricultural sensor application, where the sensor material in contact with the bulk soil greatly enhances the sensor performance in terms of sensitivity. Need of the hour is to build a custom made sensor chip array with suitable receptor layers that are of low-cost, good sensitivity, easily revivable and power efficient. On the other hand, capacitive sensors are electrical devices whose selectivity and response time depend on the changes induced in relative permittivity of the material. The combination of the duo at lower operating frequencies will have a cumulative effect on the performance of the sensors. In this direction, we fabricated a Si/SiO2 based electrode platform as the base substrate that can be eventually transformed in to an array with orthogonal sensing capability. As a result, different combinations of oxide materials such as graphene oxide (GO), vanadium oxide (V2O5), molybdenum oxide (MoO3) etc will help in realizing a receptor layer that can sense soil moisture in an efficient way. In addition, inherently, capacitive sensors are well known to be immune to temperature changes unlike resistive devices. This potentially reduces the influence of climate-induced changes in soil and thereby shows improved performance in terms of stability. In this work, we present a comparative study of graphene oxide and vanadium oxide used on parallel electrode structures and their soil moisture sensing properties. To test the validity of the method we drop casted GO and V2O5 on Si/SiO2 substrates and annealed on hot plate before wrapping with a pre-concentrator. Under laboratory conditions we have exposed both the sensor devices coated with GO and V2O5 to soil moisture at varying concentrations. We observed that the sensitivity of the GO was nearly three times higher as compared to V2O5 for any given range of gravimetric moisture content. Whereas, the response time of V2O5 was observed to be 40 seconds and that of GO was 145 seconds. Further, the temperature variation based studies conducted in the range of 25 °C to 50 °C showed an increase in the sensitivity response for both the oxides. We observed negligible change in both the oxides until 40 °C and beyond that there is a significant effect of temperature. GO showed us 30% higher sensitivity than V2O5 and was consistent until 50 °C. Thus, we conclude that GO is the potential nanomaterial over V2O5 in capacitive sensor array platform and can be used for the in-situ soil moisture sensing.



Keywords: soil moisture, temperature effect, capacitance sensor.


Graphical Abstract

Graphical Abstract






OPY-054

Detecting multiple volatile organic contaminants in water using a diamond-like carbon coated waveguide

Carina Dettenrieder1, Dervis Türkmen1, Mikael Karlsson2, Lars Österlund2, Fredrik Nikolajeff2, Boris Mizaikoff1
1Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
2Department of Engineering Sciences, Uppsala University, Uppsala, Sweden

Volatile organic compounds (VOCs) has been of interest over the last several decades due to increasing pollution of environmental waters based on increasing industrialization. VOCs occur in gasoline, diesel fuel, or other petroleum-based products, carpets, paints, varnishes, glues, spot removers and cleaners. During their production, handling, and use, VOCs are on of the most commonly detected organic pollutants. Therefore, detection of pollutants such as petroleum-based products (benzene, toluene, naphthalene, ethylbenzene and the xylene isomers) along with other hazardous pollutants (e.g., tetrachloroethylene and trichloroethylene) are an important task for national and international institutions due to their potential risk to humans, animals, and the marine ecosystem owing to their toxicity, mutagenicity, and carcinogenicity [1].

Conventionally, VOCs are detected via chromatographic methods, e.g., gas chromatography and high-performance liquid chromatography combined with a variety of detection schemes. However, such methods are time- and cost-extensive, and largely limited to laboratory-based measurements [2,3]. Attenuated total reflection infrared (ATR-IR) spectroscopy has the advantage of detecting simultaneously multiple pollutants based on their characteristic absorption features. In ATR-IR spectroscopy, diamond is already a well-known internal reflection element (IRE). It offers a broad optical transparency, high refractive index, is mechanically robust, and chemically inert [4]. However, diamond, is still very expensive. Diamond-like carbon (DLC) is composed of a mixture of sp³- and sp²-hybridized carbon, and therefore, offers similar properties as diamond. DLC allows incorporation of other elements, tailoring its properties. Incorporation of fluorine results in a high hydrophobicity, which is advantageous for applying the hydrophobic membrane. This polymeric layer (i.e., ethylene/propylene copolymer) allows enriching the hydrophobic VOCs, whereas interfering water molecules are completely excluded from the evanescent field.

This contribution focuses on recent laboratory results investigating fluorine-terminated DLC coated waveguides for VOCs analysis in aqueous solutions providing detection limits in the low ppm to ppb concentration range. Therefore, DLC coated waveguides are promising for deployment as IRE in IR sensors monitoring hazardous pollutants in environmental waters.

References:
1 R. Lu, W.-W. Li, B. Mizaikoff, A. Katzir, Y. Raichlin, G.-P. Sheng and H.-Q. Yu, Nat. Protoc., 2016, 11, 377–386.
2 R. Lu, B. Mizaikoff, W.-W. Li, C. Qian, A. Katzir, Y. Raichlin, G.-P. Sheng and H.-Q. Yu, Sci. Rep., 2013, 3, 2525–2531.
3 M. Karlowatz, M. Kraft and B. Mizaikoff, Anal. Chem., 2004, 76, 2643–2648.
4 X. Wang, M. Karlsson, P. Forsberg, M. Sieger, F. Nikolajeff, L. Österlund and B. Mizaikoff, Anal. Chem., 2014, 86, 8136–8141.



Keywords: IR-ATR spectroscopy, volatile organic compounds, environmental monitoring


A) IR attenuated total reflectance spectrum of nine VOCs, 25 ppm each, enriched from aqueous solution. B). Established calibration functions for the nine analytes.







OPY-055

Spherical graphitic carbon nitride Nano-composite with Ag2ZrO3 for photodegradation of herbicide MTSM

Tahir Muhmood, Hu Xiaobin
State Key Laboratory of Metal Matrix Composites, Shanghai JiaoTong University, Shanghai, P.R. China

Spherical graphitic carbon nitride (SCN) and its composite with Ag2ZrO3 (ZR) was synthesized fruitfully by a simple one step method, for the degradation of environmental pollutant such as herbicides. The synthesized compounds were characterized by a variety of techniques, including FT-IR., UV–Vis spectroscopy, XRD, XPS, TEM, GCMS and SEM. Photo-degradation ability was checked with BL-GHX photo-reactor. These materials were specially synthesized for the degradation of organic herbicide pollutants, (MTSM). The synthesized photo-catalyst g-C3N4-Ag2ZrO3 (SCN-ZR) showed very good photodegradation ability against the herbicide, metsulfuron methyl (MTSM). Presence of ZR particles on the surface of SCN increased the SCN-ZR surface area with the enhancement of absorption capability of visible light and retardation of recombination of electron-hole occur due to the heterojunction formation between them. SCN-ZR catalyst shows the excellent photocatalytical efficiency with high stability.
XRD pattern shows highest intense peak at 27.3˚ and low intense peak at 13˚ is the fingerprint of graphitic like carbon nitride (SCN). TEM (Fig.2) investigation represented the spherical round morphology of SCN, and also showed the successfully synthesis of SCN-ZR. UV-vis DRS is used for the optical features and it showed that SCN have sharp absorption edge in the visible region with band gap energy Eg = 2.23 eV which make SCN-ZR a perfect catalyst for work in visible light. HPLC-MS was used to study the MTSM photo-degradation pathways under visible light. The results showed that the MTSM degraded into small molecules and intermediates (fig.1). Degradation of MTSM by SCN-ZR. After 150 min the MTSM ions (m/z =382) were completed disappeared that indicate the completely degradation of MTSM by SCN-ZR. The degradation experiment was repeated up to four times for analyze the stability of SCN-ZR. In the point of conclusion spherical-C3N4 was successfully synthesized by a new novel method. The synthesized catalyst showed very good photo-degradation properties. This catalyst degrades the herbicide (metsulfuron methyl) completely. Previously researchers synthesized so many catalysts that having good properties but their properties were checked for the degradation of the dyes, and their synthesis routes were very complex,
expensive and synthesis route also generated hazardous byproducts. First time our research team develop the simple and efficient method for the synthesis of phot-catalysts that are very effective against the degradation of agricultural water pollutants such as herbicides and pesticides.



Keywords: Nano-composite, MTSM, Ag2ZrO3


Figure2. TEM image of SCN-ZR



Figure2. TEM image of SCN-ZR



Graphical Abstract







OPY-056

Validation Study of the Developed Method for the Simultaneous Determination of Some Important Aliphatic Hydrocarbons in Wastewater Samples

Barış Güzel, Elmas Öktem Olgun
TÜBİTAK Marmara Research Center, Environment and Cleaner Production Institute, Kocaeli, 41470, TURKEY

Nowadays, environmental chemistry laboratories need to more than ever fast, sensitive and accurate analytical methods to get reliable analytical data because of coming to exist a wide variety of chemicals. For this purpose, validation study of the developed method was performed for the simultaneous identification and quantification of some important aliphatic hydrocarbons in wastewater matrix by direct injection to purge & trap (PT) gas chromatography and mass spectrometer (GC-MS). It was based on selectivity, linearity, limit of detection (LOD) and limit of quantification (LOQ), accuracy (recovery), precision, trueness, and measurement uncertainty studies. The specificity study was actualized by the analysis of ten blank samples of ultrapure (de-ionized organic-free) water. The analytical response linearity in the working range (0.15-40 μg/L) could be evaluated as a great because the correlation coefficients higher than 0.998 for all analytes. The LOQ values varied from 0.058-0.296 μg/L and the LOD values varied from 0.017-0.0.09 μg/L, respectively. The method accuracy was carried out by doing recovery experiment. Recoveries of analytes are quite satisfactory ranging from 88.9 % to 93.4 % and relative standard deviations (RSDs) results were found between 3.31 % and 5.75 %. Repeatability and reproducibility (in terms of RSD for six measurements) were lower than 10% in all cases. The trueness of the method was assessed with ERA Volatiles, PriorityPollutnT QC 710 certified reference material (CRM). All the reported results are rather good when comparing with certified values. These results demonstrate that the developed method is suitable for the sensitive determination of aliphatic hydrocarbons in wastewater samples.



Keywords: Aliphatic hydrocarbons, Gas chromatography-Mass spectrometry, Wastewater





OPY-057

Decanoic Acid Fucntionalized Magnetic Particles For Sensitive Determination Of Propoxur and Fenitrothion Residues in Environmental Samples

Amine Gizem Canli1, Halil Ibrahim Ulusoy1, Bilge Sürücü1, Erkan Yılmaz2, Abuzar Kabir3, Marcello Locatelli4
1Department of Analytical Chemistry, Faculty of Pharmacy, Cumhuriyet University, Sivas, Turkey
2Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, Kayseri, Turkey
3Department of Chemistry and Biochemistry, International Forensic Research Institute, Florida International University, 11200 SW 8th St, Miami, FL 33199, USA
4Department of Pharmacy, University of Chieti–Pescara “G. d’Annunzio”, Via dei Vestini 31, Chieti 66100, Italy

A new pre-concentration and determination method which includes HPLC-DAD analysis after Magnetic Solid Phase Extraction (MSFE) has been developed for the trace amounts of two types of pesticides, Fenitrothion (FEN) and Propoxur (PRO), which can be found in environmental samples. In this proposed method, the FEN and PRO analytes were enriched with newly synthesized magnetic based nanoparticles and desorbed to a smaller volume of isopropyl alcohol prior to chromatographic determinations. Before the analysis, the samples transferred to the HPLC vials by filtration through a 0.45 μm PTFE filter. Then, samples were placed on the HPLC system and the analytical parameters such as the linear range, enrichment factor and determination limit were determined after optimizing experimental variables such as interaction time, desorption solvent, pH, etc.
In the developed method, FEN and PRO molecules were analyzed at wavelengths of 269 and 271 nm using DAD detector by using isocratic elution of 70 % acetonitrile and 30 % water. For each pesticide type, the detection and quantification limits were calculated as 1.43 and 4.71 ng mL-1, respectively. Relative standard deviation (RSD) values were lower than 3.50 % for determination of 100 ng mL-1. Finally, the developed method was successfully applied to environmental water samples and quantitative results were obtained in recovery experiments.



Keywords: Fenitrothion, Propoxur, Magnetic Solid Phase Extraction


Characterization of Magnetic Particles

A) Fe3O4 nanoparticles B) Fe3O4 nanoparticles after modification C) SEM-EDX results D) Mapping analysis of Fe3O4 nanoparticles after modification






OPY-058

Determination of volatile compounds in tea using vacuum-assisted headspace solid-phase microextraction

Mereke Alimzhanova1, Arailym Span1, Meruert Sergazina2, Zhazira Mukataeva2, Zulfiya Tukenova1
1Department chemistry and chemical technology, Al-Farabi Kazakh National University, Almaty, Kazakhstan
2Abai kazakh National Pedagogical University, Institute of Natural Sciences and Geography, Almaty, Kazakhstan

The widespread use of tea as a drink due to its pleasant smell, taste, as well as a mild stimulating effect and nutritional properties. The purpose of this work was to identify the characteristic composition of certain types of tea. The study of the chemical composition of tea helps to assess its quality and helps to control and manage the processing and storage conditions. Qualitative and quantitative analysis of volatile compounds, which gives the taste and aroma of tea, was carried out using gas chromatography gas chromatography-mass spectrometry (GC-MS). Low volatile organic compounds were analyzed using vacuum-assisted HS-SPME. This method was used to extract samples prior to determination by gas chromatography - detection using mass spectrometry. Chromatographic parameters were also optimized to determine the composition of the tea.



Keywords: Tea, vacuum solid-phase microextraction





OPY-059

Capacitive electrochemical sensor for detection of imidacloprid using molecular imprinted polymers

Suzan El Akaad1, Suzan El Akaad2, Mona A. Mohamed2, Mona A. Mohamed3, Nada S. Abdelwahab4, Eglal A. Abdelaleem4, Sarah De Saeger1, Natalia Beloglazova1, Natalia Beloglazova5, Natalia Beloglazova6
1Centre of Excellence in Mycotoxicology and Public Health, Faculty of Pharmaceutical Sciences, Ghent University, Ghent, Belgium
2Department of Pharmaceutical Chemistry, National Organization for Drug Control and Research (NODCAR), Giza, Egypt
3University Lille, CNRS, Centrale Lille, ISEN, Univ. Valenciennes, UMR 8520-IEMN, F-59000, Lille, France
4Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Benisuef University, Benisuef, Egypt
5Nanotechnology Education and Research Center, South Ural State University, Chelyabinsk, Russia
6Department of General and Inorganic Chemistry, Chemistry Institute, Saratov State University, Saratov, Russia

Imidacloprid (IMD) is a pesticide that belongs to the neonicotinoids (neonics) group. IMD was introduced to the market in 1992. Its usage accounts for 41.5% of the whole neonics. It acts on the central nervous system of invertebrates causing continuous stimulation of neurons leading to death. IMD is highly water soluble, persistent in water, soil, minimally degraded by light and not volatile, that makes it easily transported from the area of application to different environmental compartments. These properties in addition to its impact on pollinators (honey bees and bumble bees) have raised an EU concern. Over the last decade neonics have replaced other classes of pesticides in many applications. IMD was found to be toxic to sensitive aquatic invertebrates at very low concentrations (<100 ng/L). As a result of the extensive use in agriculture, its presence in the environment has increased.
Monitoring of IMD in water is essential to reduce its negative impact on health and environment. Yet, there is no legislation for a maximum residue level of IMD in river water. Therefore, it became so important to develop techniques for rapid and reliable quantification of IMD in different matrices. Many techniques based on chromatography have been developed to monitor trace levels of this compound. Although those methods are accurate, they require experienced technicians, they are time consuming, difficult for on-site determination, they need extensive sample preparation, high amounts of organic solvents and use of expensive equipment. Therefore, electrochemical methods have emerged as a promising alternative. These sensors show high sensitivity toward the template molecules, are simple and more feasible for on-site environmental applications. To enhance the selectivity of the electrochemical sensor, there has been an increasing interest in coupling the electrode surfaces with molecular imprinted polymers (MIPs).
Therefore, in this work we present a new method based on capacitive detection of IMD in aqueous samples. MIPs were synthesized using emulsion polymerization. The synthesized MIPs and non-imprinted polymers (NIPs) were characterized by TGA, DLS and SEM. Binding studies were performed for the synthesized particles using liquid chromatography tandem mass spectrometry (LC-MS/MS). The particles were coupled to the gold electrode surface by electropolymerization. The developed sensor was validated through analysis of spiked samples. Under optimal conditions, the linearity in water samples was in the range of (5-100 µM) and limit of detection was 10 µM. The proposed sensor can be used for the analysis and monitoring of IMD in environmental water samples.



Keywords: Imidacloprid, Capacitive sensor, Molecular imprinted polymers





OPY-060

Nanoparticle-Based Ferricyanide/Prussian Blue Assay for Determination of Total Antioxidant Capacity

Nergiz Kanmaz1, Ayşem Üzer2, Jülide Hızal1, Reşat Apak2
1Chemical and Process Engineering Department, Engineering Faculty, Yalova University,77100 Yalova Turkey
2Chemistry Department,Engineering Faculty,Istanbul University- Cerrahpasa, Avcilar,34320 Istanbul, Turkey

Antioxidants can be defined as substances which have oxidizable species, and they significantly retard or inhibit the oxidation of the substrate [1]. So that electron transfer-based assays measure the capacity of an antioxidant, the color of solution should be changed and the degree of color change must be related to the concentration of antioxidants in the sample. The use of ferricyanide and ferric ions as chromogenic (prussian blue) oxidants provided more suitable redox conditions for more types of antioxidants [2]. Polyvinylprrolidone (PVP) has repeating amide groups that can weakly bind to iron ions by coordinating interactions [3]. It was worked for stabilizing the prussian blue nanoparticles with PVP by mixing Fe 2+, Fe(CN)63- and PVP in water [4].
In this study, 10 mM ferricyanide, 10 mM ferric chloride solutions are mixed with antioxidant solutions in acidic medium. The mixture is incubated 20 minutes at 50 oC, then cooled to room temperature. The experiments were performed in the absence and presence of PVP. The resulting absorbance is measured against a blank at 700 nm. In this method, different antioxidants such as vitamins, flavonoids and thiols were studied. as a result high molar absorptivities were obtained. The catechins respond very well to the method, whereas the thiol group antioxidants did not work very well. In addition, cynara scolymus L. (baby artichoke) was extracted and prussian blue nanoparticle method was applied to the extract. The results were given as trolox equivalent antioxidant capacity (TEAC). Total antioxidant capacity values yielded from experiments were compared with the obtained from apllcation of CUPRAC and SDS-Modified and pH optimized Prussian Blue assays. The TEAC values of cynara scolymus L. are found as 1.74 mmol.kg-1 in the presence of PVP, and 1.97 mmol.kg-1 in the absence of PVP.

References
[1] Halliwell B, Gutteridge JMC (1989) Free radicals in biology and medicine. Oxford University Press, Oxford.
[2] Berker K. I., Guclu K., Tor I., Demirata B., Apak R., 2009, Total Antioxidant Capacity Assay Using Optimized Ferricyanide/Prussian Blue Method, Food Analytical Methods,(3), 154-168.
[3] Uemura T., Ohba M., Kitagawa S., 2004, Size and Surface Effects of Prussian Blue Nanoparticles Protected by Organic Polymers, Inorganic Chemistry, (43), 7339−7345.
[4] Uemura T., Kitagawa S., 2003, Prussian Blue Nanoparticles Protected by Poly(vinylpyrrolidone), Journal of American Chemical Society, 125, 7814-7815.



Keywords: Total Antioxidant Capacity, Fe(III) Reducing Power, Prussian Blue Nanoparticle





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