Stripping voltammetry with bismuth modified graphite-epoxy composite electrodes

The attractive performance of graphite-epoxy composite electrodes (GECE) surface-modified with a bismuth film (Bi-GECE) for simultaneous and separate stripping determination of trace amounts of heavy metals (lead, cadmium and zinc) is described. Several key parameters have been optimized. Bi-GECEi electrode shows superior accumulation properties when compared to bare GECE or even to Hg-GECE. Bi-GECE exhibits well-defined, undistorted, reproducible and sharp stripping signals with RSD of 2.99%, 1.56% and 2.19% for lead, cadmium and zinc respectively. Detection limits of 23.1, 2.2 and 600 mu g/L for lead, cadmium and zinc were obtained. Sharp peaks with high resolution (of neighboring signals) that permit convenient multi-elemental measurements resulted. The applicability of the electrodes to the real samples (tap water and soil sample) was also tested and promising results with good recoveries were obtained.