Yazar "Mulazimoglu, Ibrahim Ender" seçeneğine göre listele

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    Covalent grafting of three flavonoids onto the glassy carbon electrode surface by cyclic voltammetry
    (WALTER DE GRUYTER GMBH, 2011) Mulazimoglu, Ibrahim Ender; Ustundag, Zafer; Ozkan, Erdal; Solak, Ali Osman
    Electrochemical oxidation of quercetin (QR), 3-hydroxyfl avone (3HF), and baicalein (BN) and their grafting onto the glassy carbon (GC) electrode have been studied using the cyclic voltammetric (CV) technique. Electrochemical studies were performed within a one-compartment three-electrode cell at room temperature. The modification was carried out only in nonaqueous media, while the electrochemical characterization was done in both aqueous and nonaqueous media. In the nonaqueous experiments, 0.1 m tetrabutylammonium tetrafluoroborate in acetonitrile was used, whereas in the aqueous experiments, Britton-Robinson buffer solutions (pH = 2) and 0.1 m KCl solutions were. Surface modifi cations were performed by CV for all compounds. The presence of QR, 3HF, and BN at the GC electrode surface was characterized by CV, electrochemical impedance spectroscopy, contact angle measurement, ellipsometry, and atomic force microscopy.
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    Determination of phenol in soil sample as an environmental pollution using aminophenol modified glassy carbon sensor electrode
    (SILA SCIENCE, 2011) Mulazimoglu, Ibrahim Ender
    In this paper, a simple and sensitive method for the electrochemical determination of phenol in soil sample using disposable screen-printed glassy carbon (GC) electrode surface modified with an electrografted aminophenol film, via the electrochemical reduction of its prepared aminophenol diazonium salt in non-aqueous media, is presented. 1 mM of aminophenol diazonium salt (APDAS) in 100 mM tetrabutylammonium tetrafluoroborate (TBATFB) was used for modification of GC electrode surface in this study. The surface modification of GC electrode was performed with aminophenol (AP) using cyclic voltammetry (CV), whereas the characterization of this sensor electrode was performed using CV and electrochemical impedance spectroscopy. The modification process was carried out in non-aqueous media, whereas phenol determination was carried out in aqueous media. Acetonitrile (MeCN) for providing non-aqueous condition and Britton-Robinson (BR) buffer solution at pH 10 and 100 mM KCl solution for providing aqueous condition were used. As the final of this study, a reaction mechanism was suggested for the binding of phenol to aminophenol modified GC electrode surface. 0.1316 mgL(-1) phenol was determined in soil sample by using AP modified GC electrode.
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    Determination of quantitative phenol in tap water samples as electrochemical using 3,3 '-diaminobenzidine modified glassy carbon sensor electrode
    (ELSEVIER SCIENCE BV, 2011) Mulazimoglu, Ibrahim Ender; Mulazimoglu, Ayen Demir; Yilmaz, Ecir
    In this paper, the amount of phenol in Meram, Karatay and Selcuklu regions in Konya tap water samples was quantified in aqueous medium by using 3,3'-diaminobenzidine (DAB) modified glassy carbon (GC) electrode. The electrode surface was modified with DAB in 0.1 M tetrabutylammonium tetrafluoroborate (TBATFB) using 100 mV s(-1) scanning rate between -0.5 V and + 1.5 V with 10 cycles. For the calibration curve, a series of standard phenol solution between 1.0 x 10(-12) M and 1.0 x 10(-3) M was prepared using pH 12. The prepared standard solutions were used for the chemical binding of phenol to the modified electrode surface between 0.0 V and + 1.1 V potential range using 100 mV s(-1) scanning rate with 10 cycles. By using this calibration method, the amount of phenol was determined as 1.23 x 10(-10) M, 3.03 x 10(-8) M and 1.99 x 10(-9) M in natural tap water samples in Britton-Robinson (BR) buffer solution at pH 12. Detection limit was obtained as low as 1.0 x 10(-10) M. The presence of DAB, phenol at the GC surface and phenol of DAB modified GC electrode surface was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.
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    Electrochemical and spectroelectrochemical investigation of the behaviors of HF, 3-HF, 6-HF, 3,6-DHF on glassy carbon electrode surfaces
    (WALTER DE GRUYTER GMBH, 2011) Dundar, Ezher; Mulazimoglu, Ibrahim Ender; Ozkan, Erdal
    An electrochemical investigation of hydroxyflavone, HF; 3-hydroxyflavone, 3-HF; 6-hydroxyflavone, 6-HF; and 3,6-dihydroxyflavone, 3,6-DHF oxidation on a glassy carbon (GC) electrode was carried out using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical oxidation is a complex process, which proceeds in a cascade mechanism, related to the hydroxyl groups of HF, 3-HF, 6-HF, and 3,6-DHF molecules. The hydroxyl group is the first to be oxidized by a one-or two-electron and one-or two-proton irreversible or quasi-reversible oxidation-reduction reaction, followed by an irreversible oxidation reaction due to the hydroxyl groups. The electron and proton oxidation process at the first peak led to the formation of the corresponding quinone, which is an electrochemically active and unstable species, as evidenced by the dependence of the cyclic voltammogram profile on the applied scan rate, in agreement with the electrochemical and then chemical mechanism.
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    High energetic body source and strong antioxidant quercetin, morin and rutin: Their covalent grafting onto the glassy carbon electrode surfaces and investigation of surface properties
    (SILA SCIENCE, 2012) Mulazimoglu, Ibrahim Ender; Ozkan, Erdal; Solak, Ali Osman
    Herein, electrochemical oxidation and grafting of quercetin, morin and rutin as important biological molecules has been studied with the cyclic voltammetry technique by using a glassy carbon electrode. Electrochemical studies have beep performed potentiostatically within a one-compartment three-electrode cell at room temperature. Glassy carbon electrode was used as a working electrode and Pt was used as a wire counter electrode. Ag/Ag+ (10 mM AgNO3), non-aqueous reference electrode calibrated to the E-1/2 of ferrocene redox probe and Ag/AgCl/KCl (sat.), an aqueous reference electrode calibrated to the E-1/2 of Fe(CN)(6)(3-) redox probe respectively. The modification and surface characterizations were carried out in both aqueous and non-aqueous media. 0.1 M tetrabutylammonium tetrafluoroborate in acetonitrile was used in non-aqueous experiments, Britton-Robinson buffer solution (pH=2) and 0.1 M KCl solution were used in aqueous experiments. Before each experiment the solution was de-aerated by the bubbling of Argon to remove the oxygen effects from the experiment results. Surface modification experiments were performed in the +0.3 V and +2.8 V potential ranges with a scan rate of 0.1 V s(-1) and 10 cycles for all molecules. The presence of quercetin, morin and rutin at the glassy carbon electrode surface was characterized by cyclic voltammetry, electrochemical impedance spectroscopy and atomic force microscopy.
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    Investigation of Electrochemical Behaviour of Aminophenol Diazonium Salt Covalently Grafted onto the Glassy Carbon Electrode Surface
    (ASIAN JOURNAL OF CHEMISTRY, 2011) Mulazimoglu, Ibrahim Ender
    In this paper, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been used to investigate of the electrochemical behaviour of aminophenol diazonium salt on the modified glassy carbon (GC) electrode. The modification of aminophenol diazonium salt covalently grafted onto the glassy carbon electrode surface was performed between +0.1 and -0.9 V potential ranges for cathodic scan, 0.0 and +1.7 V potential ranges for anodic scan of 0.1 V s(-1) and 10 cycles.
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    Investigation of Electrochemical Behaviour of Quercetin on the Modified Electrode Surfaces with Procaine and Aminophenyl in Non-Aquous Medium
    (WWW PUBL PTE, 2008) Mulazimoglu, Ibrahim Ender; Ozkan, Erdal
    In this study, cyclic voltammetry and electrochemical impedance spectroscopy have been used to investigate the electrochemical behaviour of quercetin (3,3',4',5,7-pentahydroxyflavone) on the procaine and aminophenyl modified electrode. The modification of procaine and aminophenyl binded electrode surface with quercetin was performed in +0,3/+2,8 V (for procaine) and +0,4/+1,5 V (for aminophenyl) potential range using 100 mV s(-1) scanning rate having 10 cycle. A solution of 0.1 M tetrabutylammonium tetra fluoroborate in acetonitrile was used as a non-aquous solvent. For the modification process a solution of 1 mM quercetin in 0.1 M tetrabutylammonium tetrafluoroborate was used. In order to obtain these two surface, a solution of 1 mM procaine and 1 mM nitrophenyl diazonium salt in 0.1 M tetrabutylammonium tetrafluoroborate was used. By using these solutions bare glassy carbon electrode surface was modified. Nitrophenyl was reduced to amine group in 0.1 M HCl medium on the nitrophenyl modified glassy carbon elelctrode surface. Procaine modified glassy carbon electrode surface was quite electroactive. Although nitrophenyl modified glassy carbon elelctrode surface was electroinactive, it was activated by reducing nitro group into amine group. For the characterization of the modified surface I mM ferrocene in 0.1 M tetrabutylammonium tetrafluoroborate for cyclic voltammetry and 1 mM ferricyanide/ferrocyanide (1:1) mixture in 0,1 M KCI for electrochemical impedance spectroscopy were used.
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    A novel apigenin modified glassy carbon sensor electrode for the determination of copper ions in soil samples
    (ROYAL SOC CHEMISTRY, 2011) Mulazimoglu, Ibrahim Ender; Solak, Ali Osman
    In this study, electrochemical modification of a glassy carbon (GC) electrode with apigenin was carried out and the modified electrode was used for determination of copper(II) (Cu(II)) in soil samples. The GC was modified through the electrochemical polymerization of apigenin (PolyApi/GC) on the electrode surface in aqueous media. The electrode surface was modified with apigenin in phosphate buffer solution (PBS), pH 7, from 0 mV to +1400 mV potential ranges, using 100 mV s(-1) sweep rate and 30 cycles by cyclic voltammetry (CV). The surface characterizations of this sensor electrode were performed by CV, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Britton-Robinson (BR) buffer solution at pH 5 was used for determination of Cu(II) by differential pulse voltammetry (DPV). The detection limit was obtained as lower as 1.0 x 10(-11) M. By using this calibration curve, the amount of Cu(II) was determined as 7.34 x 10(-7) M in soil samples. The results showed that pH, incubation time and interferences of some cations and anions were significant.
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    Synthesis, Characterizations and Investigation of Electrochemical Behaviours of 4-[(2-Hydroxyphenylimino)methyl]benzene-1,3-diol
    (HINDAWI LTD, 2009) Mulazimoglu, Aysen D.; Mulazimoglu, Ibrahim Ender; Mercimek, Bedrettin
    This Schiff base ligand, 4-[(2-hydroxyphenylimino)methyl]benzene-1,3-diol (HIBD) was synthesized by reaction of 2-aminophenol and 2,4-dihydroxybenzaldehyde. The ligand was characterized by elemental analysis, FT-IR and H-1-NMR. Electrochemical behaviors were investigated on the glassy carbon electrode (GC) surface with cyclic voltammetry (CV). The modification of HIBD on the GC was performed in +0.3 V and +2,8 V potential range using 100 mV s(-1) scanning rate having 5 cycle. For the characterization of the modified surfaces 1 mM ferrocene redox probe in 0,1 M tetrabutylammonium tetrafluoroborate (TBATFB) and 1 mM ferricyanide redox probe in 0.1 M H2SO4 were used.