A Novel Approach to the Design of a Solid Bismuth Microelectrode Array: Applications in the Anodic Stripping Voltammetry of Cd(II) and Pb(II).

A new type of solid bismuth microelectrode array characterized by eco-friendly properties and the simplicity of its construction is presented for the first time. The proposed array of microelectrodes consists of exactly forty-three single capillaries of an inner diameter of about 10 µm filled with metallic bismuth and packed in one casing. The proposed sensor is reusable thanks to its distinctive design. The microelectrode properties of the proposed working electrodes were confirmed by comparing the analytical signals of cadmium and lead recorded from stirred and unstirred solutions during the deposition step. The practical application of the solid bismuth microelectrode array is presented by detailing the procedure for the simultaneous determination of Pb and Cd by anodic stripping voltammetry. The calibration graphs were linear from 5 × 10-9 to 2 × 10-7 mol L-1 and 2 × 10-9 to 2 × 10-7 mol L-1 for Cd(II) and Pb(II), respectively (deposition time of 60 s). The detection limits for Cd(II) and Pb(II) were equal to 2.3 × 10-9 mol L-1 and 8.9 × 10-10 mol L-1, respectively. Potential interferences were investigated. The developed procedure was successfully used for the analysis of certified water reference material and environmental water samples.