The stripping voltammograms were checked in a solution containing 30 μg L−1 of Pb(II) and 1000 μg L−1 Bi(III) in pH 4.5 acetate buffer. Very well defined peaks at about −0.60 V and −0.12 V for lead and bismuth, respectively, were found. The influence of the concentration of Bi(III) on the stripping peak of Pb(II) was studied in the range from 200 to 2000 μg L−1, each containing 30 μg L−1 of Pb(II) with a deposition time, td=120 s. As shown in Fig. 2, the height of the Pb(II) stripping peaks displayed a clear dependence on the Bi film thickness as they increased with increasing concentrations of bismuth ions from 200 to 1000 μg L−1.