Investigation of the Electrochemical Behavior of Hydroquinone at Some Conducting Polymer Electrodes and Amperometric Detection

Abstract

In this paper, a rapid and sensitive modified electrode for the determination of hydroquinone (HQ) is proposed. In this study, active compound HQ was determined from commercial drug form based on electrochemical oxidation properties at various electrodes by voltammetric methods. Electrodes modified by the electrodeposition of conducting organic polymers such as poly(3-methylthiophene, PMT), polypyrrole (PPY) and polyaniline (PAN) were used as chemical sensors for voltammetric analysis and flow injection detection of HQ. The electrochemical behavior of HQ at conducting polymer electrodes was compared and the effects on behavior of electrolyte type and its pH and the film thickness were systematically examined. The results showed that the proposed modified surface catalyzes the oxidation of HQ. Electrocatalytic efficiency decreases in order of PMT > PPY > PAN. Voltammetric peak positions were affected by the nature of the electrolyte and its pH. Also, the effect of increasing film thickness was to observe increased peak heights for oxidation potential of HQ. The best results for the determination of HQ were obtained by DPV in Na2SO4 (pH 2.0) and PMT electrodes. Polymer coated electrodes were also used in an amperometric detector for flow injection analysis of HQ. The responses of the polymer electrode were 5–15 times larger as compared to those of bare platinum. PMT showed improved performance as an amperometric detector for flow injection analysis systems over other types of polymer electrodes. Detection limits as low as 1 × 10–9 M were achieved using the PMT, compared to 1 × 10–6 M using platinum electrodes.