Bismuth-Coated Iridium Microwire Electrode for the Determination of Trace Metals by Anodic Stripping Voltammetry

This work reports the utility of an iridium microwire plated in situ with a bismuth film for the simultaneous determination of Pb(II) and Cd(II) by square-wave anodic stripping voltammetry (SWASV). The experimental variables (concentration of the bismuth plating solution, preconcentration potential, accumulation time) were investigated. The limit of detection was 1 mu g?L-1 for Pb(II) and 1.5 mu g?L-1 for Cd(II) (at 300 s of preconcentration) and the % relative standard deviations were lower than 4.9?% and 5.5?%, respectively, at the 20 mu g?L-1 level (n=8). In addition, a study was made of coating the iridium-based bismuth-film microsensor with a film of Nafion for operation in the presence of surfactants. Finally, the electrode was applied to the determination of Pb(II) and Cd(II) in wastewater and tapwater samples.