Fig. 6 shows sharp peaks for Pb2+ at −0.48 V and a linear response was obtained in the concentration range of 8 × 10−7–1 × 10−5 M. The correlation equation was I(μA) = 7.5438 [Pb(μmol)] + 6.5097 (R2 = 0.9993). The detection limit was calculated to be 7 × 10−9 M (based on 3σ). Error bars show good reproducibility of the electrode for stripping voltammetry.