ÖZNUR GÜNGÖR - Academia.edu (original) (raw)

Papers by ÖZNUR GÜNGÖR

Research paper thumbnail of Preparation and application of testosterone sensor using polyurethane membranes by square wave stripping voltammetry

DOAJ (DOAJ: Directory of Open Access Journals), May 1, 2022

Research paper thumbnail of Determination of gentamicin by using square wave anodic stripping voltammetry with poly (β-cyclodextrin-p-toluene sulfonic acid) modified glassy carbon electrode

Polymer Bulletin, Oct 4, 2023

Research paper thumbnail of High-sensitivity electrochemical sensor using no nanomaterials for the detection of ciprofloxacin with poly 2-(hydroxymethyl)thiophene-modified glassy carbon electrode

Research paper thumbnail of Preparation of a polyurethane membrane testosterone sensor and its application using square-wave stripping voltammetry

Macedonian Journal of Chemistry and Chemical Engineering

A novel electrochemical sensor for testosterone detection has been prepared by the chemical modif... more A novel electrochemical sensor for testosterone detection has been prepared by the chemical modification of a gold electrode (AuE). For the electrode modification, specific polyurethane (PU) films were synthesized from hexamethylene diisocyanate, olivetol, polyethylene glycol-100 (PEG100) and β-cyclodextrin. The synthesized PUs were investigated as selective films, and were used to coat a AuE surface at different concentrations and thicknesses. The testosterone responses of the modified electrodes were investigated by square-wave voltammetry (SWV). One separated cathodic SWV peak was obtained for testosterone at –0.390 V, with the prepared PU-modified AuE in 0.1 M phosphate buffer (PB) (pH 7.2). The linearity of testosterone responses of the prepared PU modified electrode was obtained over a concentration range of 0.1–1.0 µM (R2 = 0.995). It was observed that the response of the electrode increased regularly and sensitively with increasing testosterone amount. The detection limit, r...

Research paper thumbnail of Determination of naproxen by using differential pulse voltammetry with poly (aniline-2-sulfonic acid) modified boron doped diamond electrode

Macedonian Journal of Chemistry and Chemical Engineering

In this study, an electrochemical sensor based on a boron doped diamond electrode (BDDE) was deve... more In this study, an electrochemical sensor based on a boron doped diamond electrode (BDDE) was developed for the determination of naproxen (NAP) using a poly(aniline-2-sulfonic acid)/boron doped diamond electrode, p(A2SA/BDDE). Polymerization of A2SA was conducted in a water/acetonitrile (1:1) mixture containing 0.1 M sodium perchlorate (NaClO4) on bare BDDE and the electrochemical properties studied by cyclic voltammetry in ferricyanide/KNO3 solution. The prepared p(A2SA/BDDE) was used for detection of NAP. Effects of parameters such as monomer type and concentration, the number of cycles, and scan rate were investigated using differential pulse voltammetry (DPV) in phosphate buffer containing 0.75 mM NAP. The effect of electrolyte type and pH on DPV responses to NAP were also studied. The oxidative current peak stem from NAP concentration observed at 1.1 V potential. A linear calibration curve was obtained in the range of 0.05–1.00 mM NAP concentration. Correlation coefficient (R2),...

Research paper thumbnail of A new voltammetric sensor for penicillin G using poly(3-methylthiophene)-citric acid modified glassy carbon electrode

Diamond and Related Materials

Research paper thumbnail of Electrochemical determination of ceftriaxone using polyurethane-modified electrode containing caffeic acid and chitosan

Polymer-Plastics Technology and Materials, 2022

The aim of this work was to develop an electrochemical sensor based on caffeic acid and chitosan-... more 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 (R2) were obtained 52 µM and 0.9991 using CAC-PU modified electrode, respectively...

Research paper thumbnail of Electrochemical determination of ceftriaxone using polyurethane-modified electrode containing caffeic acid and chitosan

Polymer-Plastics Technology and Materials, 2022

The aim of this work was to develop an electrochemical sensor based on caffeic acid and chitosan-... more 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 (R2) were obtained 52 µM and 0.9991 using CAC-PU modified electrode, respectively...

Research paper thumbnail of Diazem ve Dormicum Uygulanan Ratlarda Serum İz Element Düzeylerindeki Değişimin Belirlenmesi

Journal of Inonu University Medical Faculty, 2012

Amaç: Diazem ve Dormicum nörolojik hastalıklarda yaygın olarak başvurulan ilaçlar olup kronik uyg... more Amaç: Diazem ve Dormicum nörolojik hastalıklarda yaygın olarak başvurulan ilaçlar olup kronik uygulamalarda çeşitli yan etkilere sahip olduğu tespit edilmiştir. Bu ilaçların metabolize edilme süreçlerinde, vücut için büyük hayati role sahip iz elementlerle olan ilişkisi büyük önem arz etmektedir. İnsan sağlığı ve hastalıklarda iz elementler önemli bir rol oynar. Bu nedenle çalışmamızda altı hafta süresince diazem, dormicum ve bu ilaçlarının taşıyıcıları verilen ratların kan serumlarındaki iz element seviyelerindeki değişimin araştırılması. Materyal ve Metod: Çalışmamızda diazem (diazepam) 1mg/kg, dormicum (midazolam) 0,75 mg/kg dozlarda intraperitonal olarak günde iki defa ve altı hafta boyunda uygulandı. Uygulama süreci sonrası alınan kanların serumlarında iz elementlerin ölçümü taramalı elektron mikroskobuna bağlı elektron dağılım spektroskopisi SEM-EDS kullanılarak gerçekleştirildi. Çalışmamızda serumda 32 iz element düzeyi belirlenmiş olup ilaç uygulanan gruplar ile taşıyıcı ve kontrol grupları arasında önemli değişimlerin olduğu saptanmıştır.

Research paper thumbnail of Voltammetric Determination of α-Lipoic Acid using Poly(Vanillin) Modified Platinum Electrode

In the present study electrochemical detection of α-lipoic acid (α-LA) was carried out with a pol... more In the present study electrochemical detection of α-lipoic acid (α-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 α-LA. The electrochemical oxidation of α-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 α-LA concentrations ranging from 0.03 mM to 2.00 mM at pH 5, the detection limit being of 0.025 mM. The α-lipoic acid quantification in synthetic urine samples was made by SWV with the mo...

Research paper thumbnail of Voltammetric determination of resveratrol using poly(l-phenylalanine)-modified gold electrode

Macedonian Journal of Chemistry and Chemical Engineering

In this study, we investigated the electrochemical modification of a gold electrode using poly(L-... more 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 µM, with a limit of detection (LOD) of 35.16 µM and limit of quantitation (LOQ) of 105.5 µM. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.

Research paper thumbnail of Voltammetric determination of resveratrol using poly(l-phenylalanine)-modified gold electrode

Macedonian Journal of Chemistry and Chemical Engineering

In this study, we investigated the electrochemical modification of a gold electrode using poly(L-... more 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 µM, with a limit of detection (LOD) of 35.16 µM and limit of quantitation (LOQ) of 105.5 µM. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.

Research paper thumbnail of Titanium dioxide-multiwalled carbon nanotube/polyimide composite film modified electrodes for simultaneous voltammetric detection of ascorbic acid, uric acid and dopamine as biomarker molecules

Research paper thumbnail of High Sensitive Voltammetric Gentamicin Sensor using Poly(3‐thiophenecarboxylic acid‐co‐3‐methylthiophene) Modified Glassy Carbon Electrode

Research paper thumbnail of Voltammetric determination of florfenicol by using poly(3-methylthiophene) modified glassy carbon electrode

Polymer Bulletin, 2021

In this study, poly(3-methylthiophene) modified electrode as a voltammetric sensor was developed ... more In this study, poly(3-methylthiophene) modified electrode as a voltammetric sensor was developed for the detection of florfenicol (FF). Firstly, for the modification of glassy carbon electrode (GCE), 3-methylthiophene (3-MTF) was polymerized in acetonitrile (AcN) containing tetrabutylammonium tetrafluoroborate (TBATFB) by cyclic voltammetry (CV) method. Then, in order to determine the florfenicol sensor property of 3-MTF modified GCE, parameters such as electrolyte type and electrolyte pH, scan rate, film thickness, pulse amplitude, and pulse width were investigated by using differential pulse voltammetry method (DPV). When the florfenicol responses of the modified electrode were compared to the unmodified GCE responses, it was found that the florfenicol selectivity, sensitivity, and response stability of the modified electrode were significantly increased. A linear calibration plot was obtained for florfenicol in the concentration range of 0.1–1.0 mM. From the linear calibration cu...

Research paper thumbnail of Voltammetric Determination of α-Lipoic Acid using Poly(Vanillin) Modified Platinum Electrode

In the present study electrochemical detection of α-lipoic acid (α-LA) was carried out with a pol... more In the present study electrochemical detection of α-lipoic acid (α-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 α-LA. The electrochemical oxidation of α-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 α-LA concentrations ranging from 0.03 mM to 2.00 mM at pH 5, the detection limit being of 0.025 mM. The α-lipoic acid quantification in synthetic urine samples was made by SWV with the mo...

Research paper thumbnail of Development of Gum-Arabic-based polyurethane membrane-modified electrodes as voltammetric sensor for the detection of phenylalanine

Polymer Bulletin, 2021

In this study, L-phenylalanine (L-Phe) sensors were prepared from Gum-Arabic-based polyurethanes,... more 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 µM L-Phe. The limit of detection and the limit of quantification of the prepared L-Phe selective modified electrode were calculated as 48....

Research paper thumbnail of Determination of the Change in Serum Trace Element Levels in the Rats Exposed to Diazem and Dormicum

Aim: Diazepam and midazolam are widely used medicines in neurological illnesses and there are som... more Aim: Diazepam and midazolam are widely used medicines in neurological illnesses and there are some side effects which have been observed with chronic usage of these medicines. The interaction of these medicines with trace elements during metabolisation has vital importance. Trace elements have an important role on diseases and health. For this reason, rats were exposed to diazepam and midazolam and carrriers of these medicine and determination of the change in trace elements levels was aimed in this six-week study. Material and Methods: Diazepaman and midazolam, respecitevely in 1mg/kg and 0.75 mg/kg doses, were given intraperitonally twice a day for six weeks. Trace element levels taken from the blood serum samples after giving the medicine were analyzed by SEM-EDX. The levels of 32 trace elements were determined and major differences were observed between control, carriers and experimental groups. In diazepam group, K, Fe, Cu, Zn, Se, Sb, Hg, Pb, Mn, Zr, In and Bi elements and in ...

Research paper thumbnail of Voltammetric Determination of Curcumin in Spices using Platinum Electrode Electrochemically Modified with Poly(Vanillin-co-Caffeic Acid)

In this study a simple, highly sensitive, and selective electrochemical method was developed for ... more 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 (R2) was calculated as 0.9951 from this linear calibration c...

Research paper thumbnail of Voltammetric Analysis of Melatonin and Dopamine by Using Graphene Oxide/Polyimide Based Biosensor

Bu arastirmada, melatonin (MET) ve dopaminin (DP) es zamanli analizi icin, Pt elektrodun modifika... more Bu arastirmada, melatonin (MET) ve dopaminin (DP) es zamanli analizi icin, Pt elektrodun modifikasyonu ile grafen oksit/poliimit (GO/PI) kompozit elektrot hazirlanmistir. Ilk olarak, GO/PI kompozit yapisi, 2,6-diaminopiridin temelli PI ve % 5 GO'den sentezlenmistir. Daha sonra membran olarak elde edilen kompozit yapi elektrot yuzeyi uzerine kaplanmistir. Hazirlanan GO/PI kompozit elektrodunun MET ve DP yanitlari Diferansiyel Puls Voltametri (DPV) teknigi ile arastirilmistir. MET olcumleri icin dogrusallik 85- 105 µM (R2=0.9976) konsantrasyon araliginda elde edilmistir. DP analizi icin de dogrusallik 85-105 µM konsantrasyon araliginda izlenmistir (R2=0.9988). GO/PI ile modifiye edilmis elektrodun tayin limitleri, MET ve DP icin sirasiyla yaklasik 13.45x10−5 M ve 9.61x10−5 M’di. Hazirlanan GO/PI kompozit modifiye elektrot, MET ve DP icin iyi tekrarlanabilirlik, genis dogrusal aralik ve hassasiyet sergilemistir. Elde edilen sonuclar, GO/PI kompozitinin ortamda urik asit (UA) varlig...

Research paper thumbnail of Preparation and application of testosterone sensor using polyurethane membranes by square wave stripping voltammetry

DOAJ (DOAJ: Directory of Open Access Journals), May 1, 2022

Research paper thumbnail of Determination of gentamicin by using square wave anodic stripping voltammetry with poly (β-cyclodextrin-p-toluene sulfonic acid) modified glassy carbon electrode

Polymer Bulletin, Oct 4, 2023

Research paper thumbnail of High-sensitivity electrochemical sensor using no nanomaterials for the detection of ciprofloxacin with poly 2-(hydroxymethyl)thiophene-modified glassy carbon electrode

Research paper thumbnail of Preparation of a polyurethane membrane testosterone sensor and its application using square-wave stripping voltammetry

Macedonian Journal of Chemistry and Chemical Engineering

A novel electrochemical sensor for testosterone detection has been prepared by the chemical modif... more A novel electrochemical sensor for testosterone detection has been prepared by the chemical modification of a gold electrode (AuE). For the electrode modification, specific polyurethane (PU) films were synthesized from hexamethylene diisocyanate, olivetol, polyethylene glycol-100 (PEG100) and β-cyclodextrin. The synthesized PUs were investigated as selective films, and were used to coat a AuE surface at different concentrations and thicknesses. The testosterone responses of the modified electrodes were investigated by square-wave voltammetry (SWV). One separated cathodic SWV peak was obtained for testosterone at –0.390 V, with the prepared PU-modified AuE in 0.1 M phosphate buffer (PB) (pH 7.2). The linearity of testosterone responses of the prepared PU modified electrode was obtained over a concentration range of 0.1–1.0 µM (R2 = 0.995). It was observed that the response of the electrode increased regularly and sensitively with increasing testosterone amount. The detection limit, r...

Research paper thumbnail of Determination of naproxen by using differential pulse voltammetry with poly (aniline-2-sulfonic acid) modified boron doped diamond electrode

Macedonian Journal of Chemistry and Chemical Engineering

In this study, an electrochemical sensor based on a boron doped diamond electrode (BDDE) was deve... more In this study, an electrochemical sensor based on a boron doped diamond electrode (BDDE) was developed for the determination of naproxen (NAP) using a poly(aniline-2-sulfonic acid)/boron doped diamond electrode, p(A2SA/BDDE). Polymerization of A2SA was conducted in a water/acetonitrile (1:1) mixture containing 0.1 M sodium perchlorate (NaClO4) on bare BDDE and the electrochemical properties studied by cyclic voltammetry in ferricyanide/KNO3 solution. The prepared p(A2SA/BDDE) was used for detection of NAP. Effects of parameters such as monomer type and concentration, the number of cycles, and scan rate were investigated using differential pulse voltammetry (DPV) in phosphate buffer containing 0.75 mM NAP. The effect of electrolyte type and pH on DPV responses to NAP were also studied. The oxidative current peak stem from NAP concentration observed at 1.1 V potential. A linear calibration curve was obtained in the range of 0.05–1.00 mM NAP concentration. Correlation coefficient (R2),...

Research paper thumbnail of A new voltammetric sensor for penicillin G using poly(3-methylthiophene)-citric acid modified glassy carbon electrode

Diamond and Related Materials

Research paper thumbnail of Electrochemical determination of ceftriaxone using polyurethane-modified electrode containing caffeic acid and chitosan

Polymer-Plastics Technology and Materials, 2022

The aim of this work was to develop an electrochemical sensor based on caffeic acid and chitosan-... more 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 (R2) were obtained 52 µM and 0.9991 using CAC-PU modified electrode, respectively...

Research paper thumbnail of Electrochemical determination of ceftriaxone using polyurethane-modified electrode containing caffeic acid and chitosan

Polymer-Plastics Technology and Materials, 2022

The aim of this work was to develop an electrochemical sensor based on caffeic acid and chitosan-... more 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 (R2) were obtained 52 µM and 0.9991 using CAC-PU modified electrode, respectively...

Research paper thumbnail of Diazem ve Dormicum Uygulanan Ratlarda Serum İz Element Düzeylerindeki Değişimin Belirlenmesi

Journal of Inonu University Medical Faculty, 2012

Amaç: Diazem ve Dormicum nörolojik hastalıklarda yaygın olarak başvurulan ilaçlar olup kronik uyg... more Amaç: Diazem ve Dormicum nörolojik hastalıklarda yaygın olarak başvurulan ilaçlar olup kronik uygulamalarda çeşitli yan etkilere sahip olduğu tespit edilmiştir. Bu ilaçların metabolize edilme süreçlerinde, vücut için büyük hayati role sahip iz elementlerle olan ilişkisi büyük önem arz etmektedir. İnsan sağlığı ve hastalıklarda iz elementler önemli bir rol oynar. Bu nedenle çalışmamızda altı hafta süresince diazem, dormicum ve bu ilaçlarının taşıyıcıları verilen ratların kan serumlarındaki iz element seviyelerindeki değişimin araştırılması. Materyal ve Metod: Çalışmamızda diazem (diazepam) 1mg/kg, dormicum (midazolam) 0,75 mg/kg dozlarda intraperitonal olarak günde iki defa ve altı hafta boyunda uygulandı. Uygulama süreci sonrası alınan kanların serumlarında iz elementlerin ölçümü taramalı elektron mikroskobuna bağlı elektron dağılım spektroskopisi SEM-EDS kullanılarak gerçekleştirildi. Çalışmamızda serumda 32 iz element düzeyi belirlenmiş olup ilaç uygulanan gruplar ile taşıyıcı ve kontrol grupları arasında önemli değişimlerin olduğu saptanmıştır.

Research paper thumbnail of Voltammetric Determination of α-Lipoic Acid using Poly(Vanillin) Modified Platinum Electrode

In the present study electrochemical detection of α-lipoic acid (α-LA) was carried out with a pol... more In the present study electrochemical detection of α-lipoic acid (α-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 α-LA. The electrochemical oxidation of α-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 α-LA concentrations ranging from 0.03 mM to 2.00 mM at pH 5, the detection limit being of 0.025 mM. The α-lipoic acid quantification in synthetic urine samples was made by SWV with the mo...

Research paper thumbnail of Voltammetric determination of resveratrol using poly(l-phenylalanine)-modified gold electrode

Macedonian Journal of Chemistry and Chemical Engineering

In this study, we investigated the electrochemical modification of a gold electrode using poly(L-... more 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 µM, with a limit of detection (LOD) of 35.16 µM and limit of quantitation (LOQ) of 105.5 µM. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.

Research paper thumbnail of Voltammetric determination of resveratrol using poly(l-phenylalanine)-modified gold electrode

Macedonian Journal of Chemistry and Chemical Engineering

In this study, we investigated the electrochemical modification of a gold electrode using poly(L-... more 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 µM, with a limit of detection (LOD) of 35.16 µM and limit of quantitation (LOQ) of 105.5 µM. The application of the prepared electrochemical sensor was carried out with a standard addition method in red wine samples.

Research paper thumbnail of Titanium dioxide-multiwalled carbon nanotube/polyimide composite film modified electrodes for simultaneous voltammetric detection of ascorbic acid, uric acid and dopamine as biomarker molecules

Research paper thumbnail of High Sensitive Voltammetric Gentamicin Sensor using Poly(3‐thiophenecarboxylic acid‐co‐3‐methylthiophene) Modified Glassy Carbon Electrode

Research paper thumbnail of Voltammetric determination of florfenicol by using poly(3-methylthiophene) modified glassy carbon electrode

Polymer Bulletin, 2021

In this study, poly(3-methylthiophene) modified electrode as a voltammetric sensor was developed ... more In this study, poly(3-methylthiophene) modified electrode as a voltammetric sensor was developed for the detection of florfenicol (FF). Firstly, for the modification of glassy carbon electrode (GCE), 3-methylthiophene (3-MTF) was polymerized in acetonitrile (AcN) containing tetrabutylammonium tetrafluoroborate (TBATFB) by cyclic voltammetry (CV) method. Then, in order to determine the florfenicol sensor property of 3-MTF modified GCE, parameters such as electrolyte type and electrolyte pH, scan rate, film thickness, pulse amplitude, and pulse width were investigated by using differential pulse voltammetry method (DPV). When the florfenicol responses of the modified electrode were compared to the unmodified GCE responses, it was found that the florfenicol selectivity, sensitivity, and response stability of the modified electrode were significantly increased. A linear calibration plot was obtained for florfenicol in the concentration range of 0.1–1.0 mM. From the linear calibration cu...

Research paper thumbnail of Voltammetric Determination of α-Lipoic Acid using Poly(Vanillin) Modified Platinum Electrode

In the present study electrochemical detection of α-lipoic acid (α-LA) was carried out with a pol... more In the present study electrochemical detection of α-lipoic acid (α-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 α-LA. The electrochemical oxidation of α-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 α-LA concentrations ranging from 0.03 mM to 2.00 mM at pH 5, the detection limit being of 0.025 mM. The α-lipoic acid quantification in synthetic urine samples was made by SWV with the mo...

Research paper thumbnail of Development of Gum-Arabic-based polyurethane membrane-modified electrodes as voltammetric sensor for the detection of phenylalanine

Polymer Bulletin, 2021

In this study, L-phenylalanine (L-Phe) sensors were prepared from Gum-Arabic-based polyurethanes,... more 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 µM L-Phe. The limit of detection and the limit of quantification of the prepared L-Phe selective modified electrode were calculated as 48....

Research paper thumbnail of Determination of the Change in Serum Trace Element Levels in the Rats Exposed to Diazem and Dormicum

Aim: Diazepam and midazolam are widely used medicines in neurological illnesses and there are som... more Aim: Diazepam and midazolam are widely used medicines in neurological illnesses and there are some side effects which have been observed with chronic usage of these medicines. The interaction of these medicines with trace elements during metabolisation has vital importance. Trace elements have an important role on diseases and health. For this reason, rats were exposed to diazepam and midazolam and carrriers of these medicine and determination of the change in trace elements levels was aimed in this six-week study. Material and Methods: Diazepaman and midazolam, respecitevely in 1mg/kg and 0.75 mg/kg doses, were given intraperitonally twice a day for six weeks. Trace element levels taken from the blood serum samples after giving the medicine were analyzed by SEM-EDX. The levels of 32 trace elements were determined and major differences were observed between control, carriers and experimental groups. In diazepam group, K, Fe, Cu, Zn, Se, Sb, Hg, Pb, Mn, Zr, In and Bi elements and in ...

Research paper thumbnail of Voltammetric Determination of Curcumin in Spices using Platinum Electrode Electrochemically Modified with Poly(Vanillin-co-Caffeic Acid)

In this study a simple, highly sensitive, and selective electrochemical method was developed for ... more 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 (R2) was calculated as 0.9951 from this linear calibration c...

Research paper thumbnail of Voltammetric Analysis of Melatonin and Dopamine by Using Graphene Oxide/Polyimide Based Biosensor

Bu arastirmada, melatonin (MET) ve dopaminin (DP) es zamanli analizi icin, Pt elektrodun modifika... more Bu arastirmada, melatonin (MET) ve dopaminin (DP) es zamanli analizi icin, Pt elektrodun modifikasyonu ile grafen oksit/poliimit (GO/PI) kompozit elektrot hazirlanmistir. Ilk olarak, GO/PI kompozit yapisi, 2,6-diaminopiridin temelli PI ve % 5 GO'den sentezlenmistir. Daha sonra membran olarak elde edilen kompozit yapi elektrot yuzeyi uzerine kaplanmistir. Hazirlanan GO/PI kompozit elektrodunun MET ve DP yanitlari Diferansiyel Puls Voltametri (DPV) teknigi ile arastirilmistir. MET olcumleri icin dogrusallik 85- 105 µM (R2=0.9976) konsantrasyon araliginda elde edilmistir. DP analizi icin de dogrusallik 85-105 µM konsantrasyon araliginda izlenmistir (R2=0.9988). GO/PI ile modifiye edilmis elektrodun tayin limitleri, MET ve DP icin sirasiyla yaklasik 13.45x10−5 M ve 9.61x10−5 M’di. Hazirlanan GO/PI kompozit modifiye elektrot, MET ve DP icin iyi tekrarlanabilirlik, genis dogrusal aralik ve hassasiyet sergilemistir. Elde edilen sonuclar, GO/PI kompozitinin ortamda urik asit (UA) varlig...