PRECONCENTRATION AND ELECTROANALYSIS OF COPPER SPECIES AT ELECTROCHEMICALLY ACTIVATED GLASSY-CARBON ELECTRODES

Electrochemically activated glassy carbon electrodes were applied to t he preconcentration and electroanalysis of metal species. Activated gl assy carbon electrodes were obtained by potentiostatic oxidation at +2 .0V in 0.5 M sulfuric acid. Copper species were readily extracted onto the modified electrode and were determined electrochemically. Voltamm etric peak currents showed linear response for copper concentrations i n the range between 1 to 20 mu M with a large slope of 2.11 A M-1 and a correlation coefficient of 0.997. The reproducibility of the voltamm etric measurements was found to be within 7 % RSD for five replicate m easurements on copper concentration of 10 mu M. The modified electrode s could be applied for repeated copper determinations without apprecia ble deterioration in electrode response. Results suggest that the prec oncentration of copper species onto activated electrodes involved prim arily cation-exchange interactions with the surface graphite oxide fil m.