Catalytic reduction currents in the stripping voltammetry of solutions of the system copper(II)-ascorbic acid and their application in analytical chemistry

• Published in: Journal of analytical chemistry (New York, N.Y.) Vol. 66; no. 1; pp. 66 - 72
• Main Authors: Zaitsev, P. M., Krasnyi, D. V., Surmeleva, K. V.
• Format: Journal Article
• Language: English
• Published: Dordrecht SP MAIK Nauka/Interperiodica 2011; Springer
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Copper; Copper compounds; Vitamin C; Russia; stripping voltammetry; ascorbic acid; reaction rate constant; copper; determination; catalytic current; reductant
• ISSN: 1061-9348; 1608-3199
• DOI: 10.1134/S1061934811010163

It has been found that the analytical signal from copper(II), cadmium(II), and zinc(II) in alternating-current stripping voltammetry in the presence of ascorbic acid ( AA ) increases only for copper(II) ions, which have significant oxidative potential. It is associated with the appearance of a catalytic current of the reducer in stripping voltammetry, where the reducer is AA. A scheme has been proposed for this process. The rate constant has been calculated for the chemical reduction of copper(I) ions, electrochemically produced in the diffusion layer as a result of the electrochemical oxidation of copper atoms, with AA. A procedure has been developed for the determination of copper in model solutions using the catalytic current of AA; the limit of copper detection is 0.01 μg/L, which is one order lower than the one achieved without AA.