A sensitive and selective electrochemical method was developed for determination of glutathione (GSH) in hemolysed erythrocyte using a ferrocene dicarboxylic acid modified carbon nanotubes paste electrode (FDCCNTPE). Cyclic voltammetry (CV), double potential-step chronoamperometry and differential pulse voltammetric (DPV) were used to investigate the suitability of ferrocene dicarboxylic acid at the surface of a multi-wall carbon nanotubes paste electrode as a mediator for the electrocatalytic oxidation of glutathione in aqueous solutions with various pH. The results showed that FDCCNTPE had high electrocatalytic activity for the electrooxidation of glutathione. Under optimum conditions (pH 7.00), oxidation of GSH occurs at a potential about 230 mV less positive than that at the unmodified carbon nanotubes paste electrode. The catalytic reaction rate constant,khwas calculated (1.9810 4M1 s 1) using chronoamperometry. The electrocatalytic oxidation peak current of GSH showed two linear dynamic ranges with a detection limit of 0.2mmol L1 GSH. The linear calibration ranges were obtained between 0.5–24mmol L1 and 24–122mmol L1 GSH using the DPV method. Finally, the proposed method was also examined as a selective, simple and precise electrochemical sensor for the determination of GSH in real samples such as hemolysed erythrocyte.
