Determination of trace metals by anodic stripping voltammetry using a bismuth-modified carbon nanotube electrode

A bismuth-modified carbon nanotube electrode (Bi-CNT electrode) was employed for the determination of trace lead, cadmium and zinc. Bismuth film was prepared by in situ plating of bismuth onto the screen-printed CNT electrode. Operational parameters such as preconcentration potential, bismuth concentration, preconcetraion time and rotation speed during preconcentration were optimized for the purpose of determining trace metals in 0.1 M acetate buffer solution (pH 4.5). The simultaneous determination of lead, cadmium and zinc was performed by square wave anodic stripping voltammetry. The Bi-CNT electrode presented well-defined, reproducible and sharp stripping signals. The peak current response increased linearly with the metal concentration in a range of 2-100 mu g/L. The limit of detection was 1.3 mu g/L for lead, 0.7 mu g/L for cadmium and 12 mu g/L for zinc (S/N = 3). The Bi-CNT electrode was successfully applicable to analysis of trace metals in real environments. (C) 2008 Elsevier B.V. All rights reserved.