Cathodic and anodic stripping voltammetry: simultaneous determination of As–Se and Cu–Pb–Cd–Zn in the case of very high concentration ratios

Arsenic(III), selenium(IV), copper(II), lead(II), cadmium(II) and zinc(II) are determined in environmental matrices. The voltammetric measurements were carried out using a conventional three-electrode cell and the ammonia–ammonium chloride buffer pH 9.3 as supporting electrolyte. The analytical procedure was verified by the analysis of the standard reference materials Estuarine Sediment BCR-CRM 277 and River Sediment BCR-CRM 320. The precision, expressed as relative standard deviation (sr), and the accuracy, expressed as relative error, were, in all cases, less than 5%; the detection limits, for each element and in the experimental conditions employed, were around 10−9 M. The standard addition technique significantly improved the resolution of the voltammetric method, even in the case of very high metal concentration ratios.