Determination of glutathione at enzyme-modified and unmodified glassy carbon electrodes

Abstract

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.