Bismuth film microelectrodes for heavy metals monitoring by anodic stripping voltammetry

Abstract
The preparation of bismuth film microelectrodes (BiF E), and their subsequent application to heavy metal analysis by the anodic stripping voltammetric (ASV) technique are presented. The BiF E are prepared by electrodeposition of a Bi film onto carbon and platinum disk microelectrodes, by applying both ex-situ and in-situ electroplating procedures. The analytical performance of such systems in stripping analysis is evaluated on synthetic solutions containing Cd ²⁺ and Pb ²⁺ as target ions. Firstly, the results obtained show that both carbon and platinum microdisks are suitable substrates for Bi-film formation, and that the BiF E's obtained with both the deposition procedures are effective for heavy metal deposition. The BiF E's prepared by the in-situ procedure on graphite gave the best analytical performance, in particular in terms of data reproducibility and linear range of the calibration curves. In this case, using the square wave voltammetry in the stripping step, linear calibration graphs for Cd ²⁺ and Pb ²⁺ over the concentration range M are obtained, with a RSD, at M level, within 4% (n=7). The performance of such BiF E's for trace metal analysis in real samples is also tested, and reliable data for monitoring of lead in some food products are obtained.