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Determination of gentamicin by using square wave anodic stripping voltammetry with poly (?-cyclodextrin-p-toluene sulfonic acid) modified glassy carbon electrode
(Springer, 2024) Burc, Muammer; Titretir Duran, Serap; Gungor, Oznur; Karagozler, Ali Ersin
In this study, an effective electrochemical method based on modified glassy carbon electrode was developed for the determination of gentamicin. Firstly, the poly beta-cyclodextrin-p-toluene sulfonic acid/glassy carbon electrode as gentamicin selective electrode was prepared by electropolymerization technique. In situ electropolymerization of beta-cyclodextrin and p-toluene sulfonic acid was conducted on bare glassy carbon electrode by controlled potential cycling. Characterization of the prepared poly beta-cyclodextrin-p-toluene sulfonic acid/glassy carbon electrode was performed using cyclic voltammetry and electrochemical impedance spectroscopy. Then, the effects of various parameters were investigated using square wave anodic stripping voltammetry in citrate buffer containing 4.0 mmol L-1 gentamicin. The calibration graph plotted over the range of 0.06-4.0 mmol L-1 gentamicin concentration showed high linearity. Correlation coefficient, detection limit and quantitation limit were obtained from the calibration graph as 0.9999, 3.7 mu mol L-1 and 12.4 mu mol L-1, respectively. According to these results, it is seen that the prepared poly beta-cyclodextrin-p-toluene sulfonic acid/glassy carbon electrode can be successfully used for the determination of gentamicin in many pharmacological, medical and biochemical applications.
Development of Gum-Arabic-based polyurethane membrane-modified electrodes as voltammetric sensor for the detection of phenylalanine
(Springer, 2021) Alisik, Funda; Burc, Muammer; Titretir Duran, Serap; Gungor, Oznur; Cengiz, Mahmut Alper; Koytepe, Suleyman
In this study, L-phenylalanine (L-Phe) sensors were prepared from Gum-Arabic-based polyurethanes, by the modification of Pt electrode. Firstly, Gum-Arabic-based polyurethanes were synthesized by solution polymerization technique and characterized with Fourier transform infrared spectroscopy, thermogravimetric analysis, differential thermal analysis, scanning electron microscopy and atomic force microscopy techniques. Then, L-Phe selective electrodes were prepared by coating the platinum electrode with different thickness Gum-Arabic-based polyurethane. L-Phe responses of the modified electrodes were investigated by differential pulse voltammetry technique. Sensor parameters such as scanning speed, film thickness, electrolyte type and pH were examined in detailed. Prepared electrodes were showed R-2 = 0.9972 for the concentration range of 200-1000 mu M L-Phe. The limit of detection and the limit of quantification of the prepared L-Phe selective modified electrode were calculated as 48.01 mu M and as 144.02 mu M, respectively. After ten consecutive measurements with the prepared L-Phe selective electrode, 98.8% stable result was obtained between the first and tenth reading and the RSD% value was found to be 1.21% for ten replicates. Consequently, prepared Gum-Arabic-modified sensors can be used successfully for the detection of the L-Phe with large concentration areas, high sensitivity and repeatability. [GRAPHICS] .
DEVELOPMENT OF VOLTAMMETRIC MELANIN SENSOR WITH 2,5-DIMETHYLFURAN MODIFIED PLATINUM ELECTRODE
(Soc Chemists Technologists Madeconia, 2021) Burc, Muammer; Asma, Dilek; Duran, Serap Titretir
In this study, an electrochemical sensor was developed for the electrochemical determination of melanin. For this purpose, phosphate buffer salt (PBS, pH 7.00) solution was used as an electrolyte, 2,5dimethylfuran (2,5-DMF) as a monomer, Pt wire as the auxilary electrode, Ag/AgCl electrode as the reference electrode and a platinum electrode as the working electrode. The modification of the electrode was performed by polymerization of 2,5-DMF at the bare Pt electrode surface using the cyclic voltammetry method. Parameters such as film thickness, scan rate and pulse amplitude with prepared 2,5-DMF modified platinum electrode (p(2,5-DMF)/PtE) were optimized by square wave voltammetry (SWV) in PBS buffer containing melanin. In optimum conditions, the anodic peak height showed a linear increase with the melanin concentration. The limit of detection (LOD) and limit of quantitation (LOQ) were calculated to be 0.088 mmol/l and 0.292 mmol/l, respectively, with melanin concentrations ranging from 0.10 to 2.20 mmol/l and the correlation coefficient (R2) was calculated as 0.9985. Stability of the prepared sensor was found to be 99.63% by using the reproducibility experiments (n = 15).
Development of voltammetric sensor based on polyimide-MWCNT composite membrane for rapid and highly sensitive detection of paracetamol
(Elsevier Sci Ltd, 2020) Burc, Muammer; Koytepe, Suleyman; Duran, Serap Titretir; Ayhan, Nurcan; Aksoy, Busra; Seckin, Turgay
In this work, for low level detection of paracetamol (PA) a voltammetric sensor was obtained. Polyimidemultiwall carbon nanotube (PI-MWCNT) composite film was used for modification of platinum (Pt) electrode as selective membrane. Firstly, this PI-MWCNT film was synthesized with 2,5-diaminopyridine (DAP), 4,4'-oxydiphthalic anhydride (ODPA) and MWCNT as a reinforcement by thermal imidization technique. The morphology, micro and chemical structures of the obtained composite film were studied by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and thermal analysis techniques. Then, the paracetamol sensor was prepared via the modification of Pt electrode with prepared PI-MWCNT composite film. Pt electrode was modified by coating with prepared PI-MWCNT composite film. Modified Pt electrode was used as PA sensor due to its selective membrane property in the presence of interfering substances for the electrochemical detection of PA. Electrochemical behaviour of paracetamol at the polyimide film modified Pt electrode was obtained by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) method. It has shown that the modified electrode exhibits remarkable repeatability and precision in analytical paracetamol response as compared with other modified paracetamol electrodes. Comparing the responses of modified electrode with the unmodified Pt electrode, selectivity, sensitivity and stable responses significantly enhanced. A linear calibration plot having a correlation coefficient of 0.997 was obtained in the concentration range from 0.3 to 1.8 mM paracetamol. A linear calibration plot for low concentration area having a correlation coefficient of 0.999 was obtained in the concentration range from 0.002 to 0.05 mM paracetamol. Detection limit (LOD) and quantitative limit (LOQ) for paracetamol detection of PI-MWCNT modified electrode were calculated as 0.002 mM and 0.006 mM respectively. In addition, the presented method was applied for determination of PA in commercial tablets. The recovery efficiency of the PI modified electrode was obtained range of 96% and 102% for three different tablets. As a result; a simple, rapid, low cost, repeatable method showing good accuracy and precision (99.4%) has been developed for the selective and sensitive determination of paracetamol by prepared PI-MWCNT composite film modified electrode. (C) 2019 Elsevier Ltd. All rights reserved.
Electrochemical determination of ceftriaxone using polyurethane-modified electrode containing caffeic acid and chitosan
(Taylor & Francis Inc, 2022) Hassine, Chedia Ben Ali; Gungor, Oznur; Burc, Muammer; Ozcan, Imren; Koytepe, Suleyman; Duran, Serap Titretir
The aim of this work was to develop an electrochemical sensor based on caffeic acid and chitosan-containing polyurethane (CAC-PU) films modified platinum electrode for ceftriaxone (CFX) determination. For this aim, firstly the CAC-PU structures were synthesized from three different diisocyanates and these structures were characterized with spectroscopic, thermal and surface analysis techniques. Then, these CAC-PU structures were coated on bare Pt electrode surface for the preparation of CFX selective sensors. Throughout this study several analytical parameters, such as film thickness, electrolyte type, pH effect, and scan rate were investigated by using differential pulse voltammetry (DPV) method. Under the optimized conditions, the voltammetric test results showed best analytical performances for CFX detection with a linear range from 0.1 to 1.5 mM. Limit of detection (LOD) and correlation coefficient (R-2) were obtained 52 mu M and 0.9991 using CAC-PU modified electrode, respectively. Stability of the modified electrode was found to be 96.78% by using reproducibility experiments (n = 10). Applicable of the presented sensor was tested in two synthetic urine samples and recoveries values were obtained 98.7% and 110%, respectively. The prepared modified electrode exhibits high repeatability, fast response, and high sensitivity, which makes it suitable for the detection of CFX in urine samples.
High Sensitive Voltammetric Gentamicin Sensor using Poly (3-thiophenecarboxylic acid-co-3-methylthiophene) Modified Glassy Carbon Electrode
(Wiley-V C H Verlag Gmbh, 2022) Burc, Muammer; Duran, Serap Titretir; Gungor, Oznur; Koytepe, Suleyman
For the determination of gentamicin in biomedical applications, sensitive, fast and low cost voltammetric sensor has been developed. Prepared sensor was succecfully used for determination of gentamicine in synthetic urine samples with different voltammetric measurement methods. Firstly, glassy carbon electrode was modified using cyclic voltammetry technique by electropolymerization of 3-thiophenecarboxylic acid and 3-methylthiophene. Then, optimization of the electrochemical parameters was carried out for modifed electrode. With this modified electrode, gentamicin determination was performed in the linear range of 0.05-4.00 mM. The correlation coefficient, limit of detection and limit of quantitation were calculated as 0.9999, 0.039 mM and 0.129 mM, respectively.
High-sensitivity electrochemical sensor using no nanomaterials for the detection of ciprofloxacin with poly 2-(hydroxymethyl)thiophene-modified glassy carbon electrode
(Springer, 2024) Burc, Muammer; Gungor, Oznur; Duran, Serap Titretir
In this study, a new sensor was developed for the detection of ciprofloxacin that is easy to prepare, selective and has excellent sensitivity through electrochemical polymerization of 2-(hydroxymethyl)thiophene on glassy carbon (GC) electrode. Electrode modifications were performed by using cyclic voltammetry. The morphology and surface properties of the modified electrode were characterized by using scanning electron microscopy. Determination of ciprofloxacin with poly 2-(hydroxymethyl)thiophene-modified GC electrode was performed by square wave voltammetry in 0.1 M citrate buffer (pH 5.00) at 1.1 V. The prepared sensor showed a wide linear range from 0.1 to 200 mu M, detection limit of 7 nM, a limit of quantitation of 22 nM, a correlation coefficient of 0.9993, excellent sensitivity of 99.6% and a relative standard deviation of 0.40%. The sensor was used to determine ciprofloxacin in human urine samples, and a recovery efficiency of 99.24-100.36% was obtained. According to the results in this study, we believe that the sensor developed can be used for the detection of ciprofloxacin in clinical laboratories.
A new voltammetric sensor for penicillin G using poly (3-methylthiophene)-citric acid modified glassy carbon electrode
(Elsevier Science Sa, 2022) Gungor, Oznur; Burc, Muammer; Hassine, Chedia Ben Ali; Koytepe, Suleyman; Duran, Serap Titretir
In this study, an effective voltammetric sensor was developed for determination of penicillin G by electro-polymerization of 3-methylthiophene with citric acid on glassy carbon electrode. Penicillin G selective electrode was prepared in water:acetonitrile (1:1) mixture containing 0.1 M sodium perchlorate as electrolyte medium with cyclic voltammetry. Then, the electrochemical behavior of penicillin G on poly(3-methylthiophene) based membrane modified electrode was investigated by cyclic voltammetry, differential pulse voltammetry and differential pulse stripping voltammetry techniques. When the penicillin G responses of the modified glassy carbon electrode were compared with the bare glassy carbon electrode responses, it was seen that the selectivity and sensitivity of the penicillin G responses of the modified electrode significantly increased. A linear calibration graph for penicillin G was obtained in the concentration range of 0.07 to 4.0 mM with the prepared electrode. The R2 value was calculated as 0.9999 from the linear calibration curve. The limit of detection and limit of quantitation of the poly(3-methylthiophene)-citric acid modified glassy carbon electrode for penicillin G were calculated as 8 mu M and 28 mu M, respectively. In addition, the developed electrode for the detection of PeG was applied to milk samples. The recovery efficiency of the poly(3-methylthiophene)-citric acid modified glassy carbon electrode was obtained in the range of 93 % and 103 % for three different milk samples. As a result; the modified electrode can be used for residue penicillin detection in food and biological samples.
Preparation of Molecularly Imprinted Electrochemical L-Phenylalanine Sensor with p-Toluene Sulfonic Acid Modified Pt Electrode
(Electrochemical Soc Inc, 2020) Alisik, Funda; Burc, Muammer; Koytepe, Suleyman; Duran, Serap Titretir
L-Phenylalanine (L-Phe) sensors were prepared with two steps by modifying the Pt electrode using the molecular imprinting technique. In first step, polymeric films based on p-toluene sulfonic acid (PTSA) were electropolymerized on the Pt electrode in the presence of L-Phe as template molecule. In the second step, L-Phe, the template molecule, was desorbed from the film structure coated on the electrode surface using acid. The surface properties and morphologies of the prepared modified electrodes were checked by SEM analysis technique. These modified electrodes were used for determination of L-Phe by differential pulse voltammetry (DPV). Electrodes obtained by molecular imprinting method showed R-2 = 0.9997 in the concentration range of 2-2000 mu M L-Phe. The limit of detection (LOD) of L-Phe selective electrodes was found as 0.59 mu M and the limit of quantification (LOQ) was 1.77 mu M. The first three repetition result with the same modified electrode was observed as 96.83% and the RSD value was 14.96% for ten replicates. For twenty modified electrodes, reproducibility was obtained as 97.67% stable between first electrode and twentieth electrode, and the RSD value was observed to be 2.33%. According to these results, prepared molecular imprinted electrodes have high repeatability, stability and selectivity for the determination of L-Phe.
Preparation of Molecularly Imprinted Metoprolol Sensor from Poly(aniline-co-p-toluene sulfonic acid)
(Univ Tehran, Fac Chemistry, Center Excellence Electrochemistry, 2022) Gungor, Oznur; Hassine, Chedia Ben Ali; Burc, Muammer; Koytepe, Suleyman; Duran, Serap Titretir
In this study, the metoprolol (MTP), which is a beta-blocker class molecule used in hypertension treatment, was determined by modifying the glassy carbon electrode (GCE) with a molecular imprinting technique. Firstly, p-toluene sulfonic acid (PTSA) and aniline (AN) were co-electropolymerized in the presence of MTP as a template molecule on GCE and MTP contained poly(aniline-co-p-toluene sulfonic acid) (p(AN-co-PTSA)) film was obtained. Then, the template metoprolol molecule was desorbed from the conductive p(AN-co-PTSA) film structure on the GCE surface using hydrochloric acid. Obtained molecularly imprinted electrodes were used to determine MTP by the square wave voltammetry (SWV) method. The modified electrodes obtained showed a correlation coefficient (R-2) of 0.9995 in the 40-1500 mu M MTP concentration range. The limit of detection (LOD) and the limit of quantification (LOQ) of the p(AN-co-PTSA) film modified MTP electrodes were 37.9 mu M and 126.3 mu M, respectively. A standard deviation of 1.33% was observed for the first three replicates with the same modified electrode. For the time reproduced electrodes, stable reproducibility was achieved between the first electrode result and the tenth electrode result. For the modified MTP electrode, the relative standard deviation (RSD%) value was calculated to be 2.53%. As result, the molecularly imprinted electrodes prepared with p(AN-co-PTSA) film have low response time, high reproducibility, good stability, and high selectivity for the determination of MTP.
Voltammetric Determination of ?-Lipoic Acid using Poly(Vanillin) Modified Platinum Electrode
(Univ Tehran, Fac Chemistry, Center Excellence Electrochemistry, 2020) Duran, Serap Titretir; Hassine, Chedia Ben Ali; Burc, Muammer; Gungor, Oznur
In the present study electrochemical detection of alpha-lipoic acid (alpha-LA) was carried out with a poly(Vanillin) modified platinum electrode p(VA)/PtE in Brinton Robinson buffer (BR) solution. The platinum electrode surface's was modified with cyclic voltammetry method. The prepared Pt electrode was characterized by cyclic voltammetry in ferrocyanide and scanning electron microscopy (SEM) images. The number of cycles and scan rate effects were studied using square wave voltammetry (SWV) in BR buffer containing 1 mM alpha-LA. The electrochemical oxidation of alpha-lipoic acid on the modified Pt electrode is influenced by the pH and it is an irreversible reaction in which one electron and one proton are transferred. Electrolyte type and pH effect were studied. The anodic peak current shows a linear increase with alpha-LA concentrations ranging from 0.03 mM to 2.00 mM at pH 5, the detection limit being of 0.025 mM. The alpha-lipoic acid quantification in synthetic urine samples was made by SWV with the modified Pt electrode.
Voltammetric Determination of Curcumin in Spices using Platinum Electrode Electrochemically Modified with Poly(Vanillin-co-Caffeic Acid)
(Univ Tehran, Fac Chemistry, Center Excellence Electrochemistry, 2020) Burc, Muammer; Gungor, Oznur; Duran, Serap Titretir
In this study a simple, highly sensitive, and selective electrochemical method was developed for determination of the low concentration curcumin (CUR) using a poly(vanillin-co-caffeic acid) p(Van-CA) modified platinum electrode. Electrode modification was carried out electrochemically with cyclic voltammetry (CV) method. For this purpose; a solution of 6 mM vanillin (Van) and 6 mM caffeic acid (CA) in phosphate buffer solution (PB) adjusted to pH 7.4 was used. Then, electrochemical behaviour of CUR on the platinum electrode modified with p(Van-CA) was investigated by using CV and differential pulse voltammetry (DPV) methods. Tween 20 as surfactant was used to increase the solubility and stability of CUR in this study. CUR responses of the modified electrode showed that it was selective, sensitive and stable. A linear calibration graph was acquired in the high concentration range of 0.1 to 1.0 mM CUR. Correlation coefficient (R-2) was calculated as 0.9951 from this linear calibration curve. The correlation coefficient for the low concentration range 0.01 to 0.07 mM was also calculated from 0.9950. LOD (limit of detection) and LOQ (limit of quantitation) of the developed method were determined as 0.005 mM and 0.015 mM, respectively. However, the detection of CUR in spices samples was made with this method. The recovery efficiency of the p(Van-CA) modified Pt electrode (p(Van-CA)/PtE) was calculated range of 96% and 102% for three different spices samples. Finally; developed method has been shown that it has fast, low cost, simple, reproducible, high accuracy and precision (99.6%) for sensitive and selective determination of CUR by using p(Van-CA)/PtE as effective novel electrode.
VOLTAMMETRIC DETERMINATION OF RESVERATROL USING POLY(L-PHENYLALANINE)-MODIFIED GOLD ELECTRODE
(Soc Chemists Technologists Madeconia, 2020) Gungor, Oznur; Hassine, Chedia Ben Ali; Burc, Muammer; Duran, Serap Titretir
In this study, we investigated the electrochemical modification of a gold electrode using poly(L-phenylalanine) and its applicability for the quantification of resveratrol (RESV). The gold electrode was modified with L-phenylalanine employing cyclic voltammetry (CV) in aqueous solution. The detection of RESV with the modified electrode was investigated by square wave voltammetry (SWV) in a phosphate buffer solution (PBS) (pH = 1.2). The analytical calibration curve for RESV showed a linear response with concentration in the oxidation peak current range from 50 to 1000 mu M, with a limit of detection (LOD) of 35.16 mu M and limit of quantitation (LOQ) of 105.5 mu M. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.

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