• Ana Sayfa

Fotoelektrokatalitik Sistemler İçin Redoks mediyatörleriyle Modifiye Elektrotların Hazırlanması ve Uygulamaları

Prof. Dr. DİDEM GİRAY DİLGİN

Tez Türü: Doktora

Tezin Yürütüldüğü Kurum: Ege Üniversitesi, Fen Bilimleri Enstitüsü, Kimya Anabilim Dalı, Türkiye

Tez Danışmanı: Prof. Dr. H. İsmet Gökçel

Tezin Onay Tarihi: 2014

Tezin Dili: İngilizce

Özet:

In this thesis, modified glassy carbon electrodes (GCE) were prepared by electropolymerization of four different redox mediators (hematoxylin (HT) methylene green(MG), neutral red (NR) and meldola blue (MdB)) and investigated their electrochemical behavior. The studies on electrochemical and photoelectrochemical sensors were performed using these modified electrodes. The effect of light irradiation of electrode surface on the electroctalytic oxidation of NADH, and biosensing of glucose dependent on NAD+/NADH redox couple-dehyrogenase enzyme was investigated by using both traditional voltammetric cell for cyclic voltammetry and amperometry and photo electrochemical cell for flow injection analysis (FIA) sytem. Apart from MdB, the other modified electrodes have a good response towards electrocatalytic oxidation of NADH. The peak current NADH with irradiation at these modified electrodes increased about two times compared with the reaction without irradiation. An important part of this study is the construction of photoelectrochemical biosensor for glucose using PAMAM-Glucose dehydrogenase (GDH) immobilized poly-HT/GCE which shows best response to electrocatalysis of NADH. Compared with the reaction without irradiation, the sensitivity and the detection limit increased around 2.5 and 2.0 folds, respectively. The linear range was from 1x10-5 M to 1x10-3 M with the sensitivity of 0.76 UAmM-1 and detection limit 3.0 UM without irradiation in FIA system. After the light irradiation, the linear range was from 5x10-6 M to 1x10-3 M with the sensitivity of 1.90 UAmM-1 and a detection limit of 1.5 UM. It indicated that the results shown in this thesis may found the basis for a further development for future studies in these directions.