A voltammetric sensor based on electrochemically activated glassy carbon electrode for simultaneous determination of hydroquinone and catechol

A simple and reliable voltammetric sensor for simultaneous determination of hydroquinone (HQ) and catechol (CC) was developed on an electrochemically activated glassy carbon electrode (GCE). The cyclic voltammograms in a mixed solution of HQ and CC have shown that the oxidation peaks become well resolved and were separated by 108 mV, although the bare GCE gave a single broad oxidation peak. Moreover, the oxidation peak currents of both HQ and CC were remarkably increased at the electrochemically activated GCE, which makes it suitable for simultaneous determination of these isomers. In the presence of 5.0 x 10(-5) mol L-1 isomer, the oxidation peak currents of square wave voltammograms are proportional to the concentration of HQ in the range of 1.0 x 10(-6) to 1.0 x 10(-4) mol L-1, and to that of CC in the range of 2.0 x 10(-6) to 1.0 x 10(-4) mol L-1. The corresponding detection limits for HQ and CC are as low as 1.8 x 10(-8) and 3.2 x 10(-8) mol L-1 (S/N = 3), respectively.