Electrochemical determination of Cd(ii) and Pb(ii) in mining effluents using a bismuth-coated carbon fiber microelectrode

Abstract

A new bismuth-coated carbon fiber microelectrode (BiFME) has been developed and used for the determination of Cd(II) and Pb(II) by square wave anodic stripping voltammetry (SWASV). The results indicate that cadmium and lead ions give well-defined SWASV peaks with no interference. Linear calibration curves over the range 50–350 nmol L⁻¹ for both ions were achieved, with detection limits of 9.2 and 10 nmol L⁻¹ for cadmium and lead, respectively, after applying a 180 s pre-concentration step. Nafion polymer coated BiFMEs were used for decreasing the adsorption of surfactant contaminants, tested with cetyltrimethylammonium bromide (CTAB), Triton X-100 and sodium dodecyl sulfate (SDS) in SWASV of the metal ions. This strategy allowed determination of these trace metal ions in environmental samples, and was employed to determine successfully the concentration of Cd(II) and Pb(II) in samples of mine effluents.