Determination of Trace Zn(II), Cd(II) and Pb(II) Metal Ions Using In-situ Bismuth-modified Boron Doped Diamond Electrode

Bismuth modified boron doped diamond (BDD) film electrode was employed for simultaneous determination of trace Zn(II), Cd(II) and Pb(II) by anodic stripping voltammetry. Bi(III) was simultaneously in. situ deposited on bismuth modified boron doped diamond electrode with Zn(II), Cd(II) and Pb(II) by pre-concentration. In the presence of Bi(III), the sensitivity for determination of Zn(II), Cd(II) and Pb(II) was remarkably enhanced. Influence factors such as bismuth concentration, boron doped concentrations of BDD electrode, pH, preconcentration potential were investigated and optimized. Under the optimal conditions, the stripping peak currents increased linearly with the increasing concentration of Zn(II), Cd(II) and Pb(II) in the range of 10-300 mu g/L. The limit of detection was 0.56 mu g/L for Zn(II), 0.32 mu g/L for Cd. and 0.75 mu g/L for Pb(II) (S/N = 3), respectively. The interference experiments showed that common ions had little influence on the determination except Cu(II). In addition, the developed electrode displayed a good repeatability. The method was successfully applied to determination of Zn(II), Cd(II) and Pb(II) in real water samples with the standard addition recoveries of 92.0%-114.0%.