Photoelectrocatalytic oxidation of NADH using phenothiazine type dyes modified glassy carbon electrode

In this study the modified glassy carbon electrodes were prepared by electropolymerization of phenothiazine type redox dyes such as, Methylene blue and Azure A. The studies on electrocatalytic and photoelectrocatalytic oxidation of NADH using these modified electrodes were performed by using traditional voltammetric cell for cyclic voltammetry and amperometry.The parameters during the preparation of each modified electrode such as supporting electrolyte type or its pH, monomer concentration, cycle number and potential window were optimized according to their best response toward NADH. The effect of the scan rate, pH of the supporting electrolyte on the modified electrodes and the their stability were investigated with cyclic voltammetry.The electrocatalytic oxidation of NADH was investigated with amperometry and cyclic voltammetry methods using these modified electrodes and it was determined all of modified electrodes showed a good electrocatalytic effect on NADH.With the same methods, when the surface of modified electrodes was illuminated by a fiber optic halogen lamp, it was concluded that the electrocatalytic oxidation current response of NADH increased about 1,5-2 times compared with that exhibited without irradiation. For each modified electrode, the concentration of NADH versus peak currents were investigated and a linear concentration range was obtained between 1.0x10-6-1.0x10-3 M.