Electrochemical Investigation of 4-[(2-Hydroxy-1- naphthyl)azo]benzenesulfonic Acid Sodium Salt (Orange II) at Glassy Carbon Electrode

Abstract

The electrochemical behaviour of 4-[(2-hydroxy-1- naphthyl)azo]benzenesulfonic acid sodium salt (orange II) at glassy carbon electrode in aqueous solutions was investigated. Orange II was found to give a single sharp cathodic CV peak that is found to correspond to a gain of 4 electrons per molecule. The diffusion coefficient was calculated by the aid of chronoamperometric data, the number of electrons transferred was calculated by controlled potential electrolysis and the standard rate constant for the reduction was calculated by Klingler-Kochi technique. From the electrochemical data obtained by using these techniques and thin layer chromatography in aqueous solutions of varying pH, a plausible reduction mechanism of the azo dye was proposed.