Electrochemical determination of ascorbic acid using Cu sulfide modified glassy carbon electrode

Resumo

The electrochemical responses of ascorbic acid at the Cu-sulfide modified glassy carbon electrode have been analyzed by adjusting the scan rate, ascorbic acid concentration and species of the electrolytes. Two anodic cyclic voltammogram peaks (cvp1, cvp2) are located at +0.56 V and +0.33 V, and two cathodic cyclic voltammogram peaks (cvp1′, cvp2′) are located at +0.10 V and–0.40 V, respectively. The intensities of the cyclic voltammogram peaks increase linearly with the increase of the ascorbic acid concentration in a range of 0.0005–2 mM and scan rate ranging from 25 to 200 mV s^–1. A Cu-sulfide modified glassy carbon electrode shows good determination ability for ascorbic acid in neutral solutions with the detection limit of 0.18 μM and 0.12 μM for cvp1 and cvp2, respectively, at a signal-to-noise ratio of 3. Cu sulfide modified glassy carbon electrode shows good reproducibility and stability.