Volume 46, Number 5  (September - October 2001)

Key words:  reticulated vitreous carbon, mercury film electrode, stripping analysis, trace metals

Good quality mercury films for cadmium and lead determination by square wave stripping voltammetry are deposited at -0.9 V vs Ag/AgCl for 5 min from a 50 mg l^-1 Hg²⁺ solution in acetate buffer. The influence of the experimental parameters (deposition potential and time, flow-rate, Hg concentration) on the mercury amount deposited are discussed. The quantitative dissolution of mercury film from the reticulated vitreous carbon electrode (RVC) is achieved by electrochemical anodic stripping at +0.4 V in the thiocyanate medium (0.1 mol l^-1 NH₄CNS and 1 mol l^-1 KCl). In spite of well-defined stripping peaks, up to 40 % of mercury remaines on the RVC electrode  after the stripping in a non-complexing media. Mercury film deposition/stripping using the reticulated vitreous carbon and glassy carbon electrodes are compared.