Polarographic and voltammetric investigation of 8-hydroxy-7-(4-sulfo-1-naphthylazo)-5-quinoline sulfonic acid

The behaviour at HMDE and SMDE of 8-hydroxy-7-(4-sulfo-1-naphthylazo)-5-quinolinesulfonic acid has been studied by several techniques including Square wave voltammetry (SWV), Differential pulse plarography (DPP), Direct current polarography (DCP) and Cyclic voltammetry (CV). Current-potential curves recorded at HMDE and SMDE electrode provide information on electrode reaction mechanism. The reduction of a pre-protonated azo group involving a four-electron process and two peaks or waves, gives amine derivatives in acidic solutions. In alkaline solution the reduction process occurs at more negative potential with the formation of a stable hydrazo compound. The electrochemical reduction mechanism of the azo compound is suggested using SWV, DPP, DCP and CV techniques in aqueous solutions of varying pH.