A simultaneous and Sensitive Determination of Hydroquinone and Catechol at Anodically Pretreated Screen-Printed Carbon Electrodes

[[abstract]]Hydroquinone (HQ) and catechol (CA) are two positional isomers of dihydroxybenzene. They usually coexist in environmental samples and bring about pollution in our living environment. This research has developed a cheap, sensitive, and rapid method for the electrochemical determination of HQ and CA in aqueous pH 6.0 buffer solution without previous separation. By employing both anodically pretreated screen-printed carbon electrodes (SPCE*) and square wave voltammetric techniques, a direct and simultaneous determination of the two positional isomers was achieved. The oxidation peak potentials for HQ and CA were completely separated at the SPCE*, exhibiting well-defined and quasi-reversible redox peaks and showing greatly enhanced activity. Under optimized conditions, the linear calibration ranges for HQ and CA were in the ranges of 0.1-50 and 0.1-70 mu M, with detection limits (S/N = 3) of 0.05 and 0.05 mu M, respectively. This method was applied to the direct determination of HQ and CA in river water with satisfactory recovery results.[[note]]SC