Electrocatalytic Determination of Glutathione Using Transition Metal Hexacyanoferrates (MHCFs) of Copper and Cobalt Electrode Posited on Graphene Oxide Nanosheets

A glassy carbon electrode was modified with graphene oxide nanosheets and a hybrid of copper-cobalt hexacyanoferrate. The electrode surface was characterized by scanning electron microscopy. Cyclic voltammetry showed a stable and reversible redox pair with surface confined characteristics in phosphate buffer solution (pH 3). The prepared electrode showed electrocatalytic properties in the heterogeneous electron transfer process of glutathione. Hydrodynamic amperometry was used for determination of glutathione at pH 3. The catalytic oxidation peak current varied linearly with the concentration of glutathione in the range of 3.3 × 10-7-5.5 × 10-5 M with a limit of detection of 2.5 × 10-7 M. The repeatability was evaluated for 5 successive measurements of glutathione (0.48 mM) by the proposed method as relative standard deviation (RSD%), which was 3.02%. When 3 different electrodes were used, RSD% for glutathione etermination was 3.34%. Determination of glutathione in hemolysed erythrocyte samples by the proposed method was satisfactory, compared to the standard method.