Determination of heavy metals in wines by anodic stripping voltammetry with thick-film modified electrode

A method has been developed for determination of copper, lead, cadmium and zinc concentration in dry wines by stripping voltammetric with a thick-film modified graphite-containing electrode (TFMGE). This method does not require the preliminary acid digestion of the sample or other approaches for the destruction of organic substances. The optimal conditions for the determination of these elements in wines have been chosen. Supporting electrolyte was 0.5 M HCl for Cu, Pb and Cd, and 0.1 M acetate buffer (pH 5.5) and 0.35 M NaCl for Zn. The accumulation potential was -0.8 V for Cu, -1.2 V for Ph and Cd, and -1.4 V for Zn. The degree of wine dilution with the supporting electrolyte was 1:1.1 for Cu, Ph and Cd, and 1:50 for Zn. The accumulation time was 30-60 s for copper, 120 s for lead and cadmium, and 10-30 s for zinc. Results obtained under the chosen conditions with the use of TFMGE were compared with those obtained using ICP-MS for the final determination of the selected elements. Moreover, it was shown that the proposed method provided better reproducibility than methods involving wine decomposition. (C) 2004 Elsevier B.V. All rights reserved.