DETERMINATION OF GLUTATHIONE AT ENZYME-MODIFIED AND UNMODIFIED GLASSY-CARBON ELECTRODES

The oxidation of the reduced form of glutathione (GSH) was found to occur at a decreased overpotential at a glassy carbon electrode when 1.2 mol dm-3 of dipotassium hydrogen phosphate were used as the supporting electrolyte. The resulting current for the oxidation peak of GSH varied linearly over the concentration range 0.16-2.4 mmol dm-3 GSH. The reaction between GSH and hydrogen peroxide catalysed by the enzyme GSH-peroxidase (GSH-PX) could be monitored using a glassy carbon electrode with GSH-PX immobilized under a layer of Nafion film.