Abstract
A simple, rapid and a highly selective method for the direct electrochemical determination of catechol based on the electrochemical oxidation at the screen printed graphite electrode was discussed. The electrochemical behavior of catechol was studied by cyclic voltammetric techniques at the screen printed graphite electrode. Catechol showed one anodic peak (E(pa)) and one cathodic peak (E(pc)) at 204 and 145 mV (vs. SCE), respectively, in phosphate buffer (pH 6). Square wave voltammetry was used for the direct electrochemical determination of catechol. The effect of different experimental and instrumental parameters such as; type of supporting electrolytes, solution pH, applied potential, and scan rate were examined. The oxidation peak currents showed a linear range from 1x10(-6) to 1x10(-4) M with a 0.999 correlation coefficient. A 2.9x10(-7) M lower detection limit was obtained. The effect of ascorbic acid as the most interfering substances on the peak height of catechol was examined. Using square wave voltammetry, catechol and ascorbic acid showed a well defined two separated oxidation peaks. The proposed method has been applied for the determination of catechol in the absence and presence of ascorbic acid in a water sample.