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  • Küçük Resim
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    Bazı kinonik yapıların karbon elektrot yüzeylerin modifikasyonunda kullanılması ve hazırlanan modifiye yüzeylerde nanopartikül etkisi ve uygulama alanlarının araştırılması
    (Selçuk Üniversitesi Fen Bilimleri Enstitüsü, 2014-01-21) Tok, Mutahire; Yazıcıgil, Zafer
    Bu tez çalışmasında; 1,10-fenantrolin-5,6-dion ve 9,10-fenantrakinon maddelerinin dönüşümlü voltametri tekniği ile camsı karbon (GC) elektrot yüzeyinde elektrokimyasal yükseltgenmesi sonucu 1,10-fenantrolin-5,6-dion modifiye camsı karbon (PD/GC) ve 9,10-fenantrakinon modifiye camsı karbon (PQ/GC) elektrot yüzeyleri hazırlanmıştır. Yüzey modifikasyon deneyleri 1,10-fenantrolin-5,6-dion ve 9,10-fenantrakinon maddelerinin 100,0 mM tetrabütilamonyum tetrafloroborat içeren asetonitril ortamında hazırlanan 1,0 mM'lık çözeltilerinde, +1,5/+2,7 V potansiyel aralığında, 100 mV/s tarama hızında 50 döngülü olarak Ag/Ag+ referans elektroduna karşı gerçekleştirilmiştir. Bu şekilde hazırlanan modifiye elektrot yüzeyleri; redoks problar varlığında dönüşümlü voltametri ve elektrokimyasal impedans spektroskopisi teknikleri ile karakterize edilmiş ve elde edilen karakterizasyon sonuçları yalın GC elektrot yüzeyine ait verilerle karşılaştırılmıştır. Ayrıca; PD/GC ve PQ/GC elektrot yüzeyleri çeşitli nano yapılarla türevlendirilmiş ve yeni bir morfoloji kazandırılan elektrotların non-enzimatik glukoz sensör olarak uygulanabilirliği araştırılmıştır.
  • Küçük Resim Yok
    Öğe
    Copper nanoparticle modified carbon electrode for determination of dopamine
    (PERGAMON-ELSEVIER SCIENCE LTD, 2012) Oztekin, Yasemin; Tok, Mutahire; Bilici, Esra; Mikoliunaite, Lina; Yazicigil, Zafer; Ramanaviciene, Almira; Ramanavicius, Arunas
    This paper reports the synthesis and characterization of copper nanoparticles (CuNPs) and application of copper nanoparticle-modified glassy carbon electrode for the electrochemical determination of dopamine. Electrochemical measurements were performed using differently modified glassy carbon (GC) electrodes. Bare, oxidized before modification and copper nanoparticle-modified glassy carbon electrodes (bare-GC, ox-GC and CuNP/GC electrodes, respectively) were characterized by cyclic voltammetry and electrochemical impedance spectroscopy in the presence of redox probes. Atomic force microscopy was used for the visualization of electrode surfaces. The CuNP/GC electrode was found to be suitable for the selective determination of dopamine even in the presence of ascorbic acid, uric acid, and p-acetamidophenol. The observed linear range of CuNP/GC for dopamine was from 0.1 nM to 1.0 mu M while the detection limit was estimated to be 50 pM. It was demonstrated that here reported glassy carbon electrode modified by copper nanoparticles is suitable for the determination of dopamine in real samples such as human blood serum. (C) 2012 Elsevier Ltd. All rights reserved.
  • Küçük Resim Yok
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    Electrochemical determination of copper(II) using modified glassy carbon electrodes
    (DESALINATION PUBL, 2012) Bilici, Esra; Yazicigil, Zafer; Tok, Mutahire; Oztekin, Yasemin
    Electrochemical modification of glassy carbon (GC) electrode surface via electrochemical oxidation of 1-aminoindan in acetonitrile including 100.0 mM of tetrabutylammonium tetrafluoroborate and applicability of electrode modified in this way for electrochemical determination of copper(II) (Cu(II)) were reported in this study. Electrochemical surface modification was performed by cyclic voltammetry in the potential range between +0.9 and +1.5V vs. Ag/Ag+ (10.0 mM of AgNO3) at the scan rate of 100 mV/s by 30 potential cycles. The modified electrode surface was characterized by cyclic voltammetry, electrochemical impedance spectroscopy and contact angle measurement. The characterization results were compared with the characterization results of bare GC electrode. The results of the amperometric measurements of the modified GC electrode towards Cu(II) ions were investigated. It was determined that the modified electrode surface had electrochemical responses towards Cu(II) ions with high sensitivity, good selectivity, stability, reproducibility and repeatability. According to the results, it is believed that it will be possible to find an application area for this new surface in any industrial fields.
  • Küçük Resim
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    Electrochemical Modification of Glassy Carbon Electrode by Poly-4-Nitroaniline and Its Application for Determination of Copper(II)
    (Pergamon-elsevier Science Ltd, 2010) Öztekin, Yasemin; Tok, Mutahire; Nalvuran, Hande; Kıyak, Saliha; Göver, Tuğçe; Yazıcıgil, Zafer; Ramanaviciene, Almira; Ramanaviciusi, Arunas
    Electrochemical modification of glassy carbon (GC) electrode by poly-4-nitroaniline (P4NA), electrochemical reduction of P4NA and applicability of electrode modified in this way for determination of copper(II)(Cu(II)) is reported in this study. Electrochemical surface modification was performed by cyclic voltammetry in the potential range between +0.9V and +1.4V vs. Ag/Ag+ (in 10 mM AgNO3) at the scan rate of 100 mV/s by 100 cycles in non-aqueous media. In order to provide electrochemical reduction of nitro groups on the P4NA-modified GC electrode surface (P4NA/GC), the cyclic voltammograms inducing/evidencing the reduction of nitro groups were performed in the potential range between -0.1 V and -0.8 V vs. Ag/AgCl/(sat.KCI) at the scan rate of 100 mV/s. The reduced P4NA/GC surfaces (Reduced-P4NA/GC) were treated with aqueous solution of nitrilotriacetic acid. The sensitivity of GC electrode modified in described way towards Cu(II) was investigated in Britton-Robinson buffer solution, pH 5.0. The potentiometric generic pulse technique was applied as innovative electrochemical method for detection of analytical signal. It was shown that GC electrodes modified in here described way will be suitable for the determination of Cu(II) in technological waste water and/or some other solutions containing Cu(II) ions.