Determination of trace heavy metals by sequential injection-anodic stripping voltammetry using bismuth film screen-printed carbon electrode

A sequential injection-square-wave anodic stripping voltammetry (SIA-SWASV) is proposed for the simultaneous determination of Pb(II), Cd(II) and Zn(II), employing an in situ plated bismuth film screen-printed carbon electrode (Bi-SPCE) as a working electrode and hydrochloric acid as a supporting electrolyte. Bi(III) and analyte metal ions were on-line deposited onto a SPCE at -1.4 V vs. Ag/AgCl for 180 s. At a stopped flow, a square-wave voltammogram was recorded from -1.3 to 0 V vs. Ag/AgCl. The experimental conditions were optimized. Under the optimum conditions, the linear ranges were 0 - 70 mu g L-1 for Pb(II) and Cd(II), and 75 - 200 mu g L-1 for Zn(II). The limits of detection (S/N = 3) were obtained at concentrations as low as 0.89 mu g L-1 for Pb(II) and 0.69 mu g L-1 for Cd(II) for a 180-s deposition time. The proposed method was applied to the determination of Pb(II), Cd(II) and Zn(II) in water samples with satisfactory results.