Voltammetric analysis of hydroquinone, ascorbic acid, nitrobenzene and benzyl chloride in aqueous, non-aqueous, micellar and microemulsion media

Abstract

Voltammetric behaviour of hydroquinone, ascorbic acid, nitrobenzene and benzyl chloride in aqueous, micellar, microemulsion and aprotic media on glassy carbon electrode under identical experimental conditions was compared. A general trend of decreasing peak currents in the order \( i_{{p{\left( {micelle} \right)}}} > i_{{p{\left( {aqueous} \right)}}} > i_{{p{\left( {DMF} \right)}}} > i_{{p{\left( {\mu E} \right)}}} \) was noticed. The only exception was hydroquinone, which exhibited a slightly lower current in micellar medium. The peak potentials for each of these compounds varied in the order \( E_{{P{\left( {DMF} \right)}}} > E_{{P{\left( {\mu E} \right)}}} > E_{{P{\left( {aqueous} \right)}}} > E_{{P{\left( {micelle} \right)}}} \) with due consideration for the two oxidation and reduction processes (negative EP values for reduction). In micellar systems, which contain a predominantly aqueous phase where the cationic surfactant exhibits a catalytic effect, lower peak potentials and higher current are obtained. The peak potential and peak current is lower in microemulsion when compared to aprotic medium. The causes for such systematic variations and their analytical implications are discussed.