Anodic Stripping Voltammetry at Bismuth‐Coated and Uncoated Carbon Microdisk Electrodes: Application to Trace Metals Analysis in Food Samples

Abstract

This article reports on the performance of a bismuth‐coated carbon microdisk electrode (BiFμE) for the determination of trace heavy metals by anodic stripping voltammetry (ASV). The BiFμE was prepared by electrodeposition of a metallic bismuth film onto the microdisk, by applying an in‐situ electroplating procedure. To test the performance of the BiFμE, ASV measurements were performed on synthetic solutions containing Cd²⁺, Pb²⁺, and Cu²⁺ as target ions. The results indicated that cadmium and lead gave well‐defined ASV peaks with no interference, and their quantitative determination could be carried out straightforwardly. In particular, linear calibration curves over the range 5.0 × 10⁻⁸–1.0 × 10⁻⁶ M for both ions, and detection limits of 7.8 and 2.9 nM, for cadmium and lead, respectively, after applying a 60 sec preconcentration step, were obtained. The reproducibility was also satisfactory, the relative standard deviation (RSD) being within 2.5% for both ions. Copper, instead, gave an ASV response that, in most experimental conditions, overlapped with that of bismuth. This circumstance made the determination of copper at the BiFμE difficult. Since the latter element could be detected reliably at the uncoated carbon microdisk electrode (CμE), both BiFμE and CμE were employed, respectively, for the determination of lead and copper ions in drinking water, wine, and tomato sauce.

Keywords:

• Bismuth‐coated microdisk electrode
• Carbon microdisk electrode
• Anodic stripping voltammetry
• Trace metals
• Food analysis

Acknowledgment

Financial support by MIUR, Rome (also for Project 20/Cluster C22: Metodologie di Monitoraggio, Analisi e proposte di Risanamento Ambientale) is gratefully acknowledged.