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 nanocomposite was characterized by cyclic voltammetry, FT-IR and scanning electron microscopy. Cyclic voltammetry showed a stable and reversible redox pair with surface confined characteristics in phosphate buffer solution (0.1 M, pH 3). 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 to 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 a GSH solution (0.48 mM) by the proposed method as relative standard deviation (RSD%), which was 3.02%. When 3 different electrodes were used, the RSD% for GSH determination was 3.34%. The modified electrode was used in the determination of glutathione in hemolysed erythrocyte samples with satisfactory results.