Detemination of traces of metals by anodic stripping voltammetry at a rotating glassy carbon ring-disc electrode : Part 3. Evaluation of Linear Anodic Stripping voltammetry with Ring Collection for the Determination of Cadmium, Lead and Copper in Pure Water and High-Purity Sodium Chloride, and of Cadmium, Lead, Copper, Antimony adn Bismuth in Sea Water

Abstract

A procedure based on linear anodic stripping voltammetry (a.s.v.) with ring collection is described for the determination of cadmium, lead and copper in very pure doubly-distilled water passed through a Millipore Milli-Q purification system and in commercial Suprapur sodium chloride. Concentrations of Cd, Pb and Cu as low as 6, 8 and 5 ng l −1 respectively, were measured in water and 0.12, 0.15 and 0.30 ng g −1 in sodium chloride. Results obtained for Cd, Pb, Cu, Sb and Bi in sea water by two different methods (linear a.s.v. with a ring-disc electrode and differential pulse a.s.v. with a hanging mercury drop electrod) were in good agreement for u.v.-irradiated samples; linear a.s.v. with the ring-disc electrode gave systematically higher Cd, Pb and Cu contents because of exchange of mercury(II) ions added to the solution, with the heavy metal non-labile complexes.