Mercury film deposition and anodic stripping using the reticulated vitreous carbon flow-through electrodes for analysis of trace metals

Good quality mercury films for cadmium and lead determination by square wav e 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 experime ntal parameters (deposition potential and time, flow-rate, Hg2+ concentrati on) on the mercury amount deposited are discussed. The quantitative dissolu tion of mercury film from the reticulated vitreous carbon electrode (RVC) i s achieved by electrochemical anodic stripping at +0.4 V in the thiocyanate medium (0.1 mol l(-1) NH,CNS and 1 mol l(-1) KCl). In spite of well-define d stripping peaks, up to 40% of mercury remains 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 comp ared.