Trace metal analysis by stripping voltammetry at a bismuth-coated iridium microdisc electrode

Abstract

This work describes an electrochemical sensor prepared by electroplating in situ a bismuth film on an iridium disk microelectrode. The iridium-based bismuth-film electrode (BiFE) was applied for the 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, SW parameters) were investigated. The limits of detection were 1 μg L-1 for Pb(II) and Cd(II) (at 300 s of preconcentration) and the % relative standard deviations were than 4.2 % and 5.1 %, respectively, at the 20 μg L-1 level (n=10). In addition, preliminary experiments have demonstrated the utility of the sensor for the determination of other heavy metals (In(III) and Tl(I)). Finally, the iridium-based BiFE was applied to the determination of Pb(II) in tap water.