Highly Sensitive and Simultaneous Determination of Hydroquinone and Catechol at Thionine/Graphene Oxide Modified Glassy Carbon Electrodes

Abstract

A highly sensitive electrochemical method for the simultaneous and quantitative detection of hydroquinone (HQ) and catechol (CC) was developed, based on covalent immobilization of thionine (TH) by Schiff-base reaction between –NH2 of TH and –COH onto graphene oxide modified glassy carbon electrodes (GO/GCE). The modified electrode showed excellent electrocatalytic activity and reversibility toward the oxidation of both HQ and CC in 0.1 M phosphate buffer solution (PBS, pH 7.0). The redox responses from the mixture of HQ and CC were clearly resolved in both cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with the peak differences of 100 mV and 110 mV, respectively. The oxidation peak currents of HQ and CC were linear over the range from 1 to 200 μM in the presence of 150 μM of counterpart. The detection limits (S/N = 3) for HQ and CC were 20 and 25 nM, respectively. Furthermore, the electrochemical performances with some interference were studied. The developed sensor was successfully examined for real sample analysis with tap water and revealed stable and reliable recovery data.