Electrochemical and spectroelectrochemical investigation of the behaviors of HF, 3-HF, 6-HF, 3,6-DHF on glassy carbon electrode surfaces

Abstract

An electrochemical investigation of hydroxyflavone, HF; 3-hydroxyflavone, 3-HF; 6-hydroxyflavone, 6-HF; and 3,6-dihydroxyflavone, 3,6-DHF oxidation on a glassy carbon (GC) electrode was carried out using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrochemical oxidation is a complex process, which proceeds in a cascade mechanism, related to the hydroxyl groups of HF, 3-HF, 6-HF, and 3,6-DHF molecules. The hydroxyl group is the first to be oxidized by a one- or two-electron and one- or two-proton irreversible or quasi-reversible oxidation-reduction reaction, followed by an irreversible oxidation reaction due to the hydroxyl groups. The electron and proton oxidation process at the first peak led to the formation of the corresponding quinone, which is an electrochemically active and unstable species, as evidenced by the dependence of the cyclic voltammogram profile on the applied scan rate, in agreement with the electrochemical and then chemical mechanism.

Keywords

• cyclic voltammetry
• flavonoid
• surface characterization
• surface modification