Voltammetric Determination of Small Amounts of As, Sb and Sn in Waters, Leaches and Materials with a Complex Matrix

Abstract

A very sensitive method is described for the determination of As, Sb and Sn separately, in a mixture, or in the presence of a large excess of interfering elements. This is enabled by practically selective extractive separation in the form of covalent bromides which, at the same time, trasfers quantitatively As, Sb and Sn into a polarographically active form. Final procedure makes it possible to determine, in one solution, first Sb and Sn by anodic stripping voltammetry, after accumulation on a hanging drop Hg electrode at -0.60 V (against SCE), and then As by cathodic stripping voltammetry, after addition of an excess of Cu and accumulation at -0.48 V. The limits of determination are about 1 microg.l^-1. Various interfering effects and their elimination are described. The method has been used for circular analyses of waste and surface waters ASLAB and determinations of the given elements in leaches of glass and waste from glass production.