Batch injection analysis with adsorptive stripping voltammetry for the determination of traces of nickel and cobalt

Abstract

Square wave adsorptive stripping voltammetry (AdSV) in conjunction with the batch injection analysis technique has been investigated at mercury thin-film electrodes, using analysis of nickel and cobalt ions with nioxime ligand as example, and injection of sample volumes of le100muL. Experiments were conducted in a HEPES neutral buffered medium, suitable for analysis of biological fluids. Sensitivity is maximized by continuing the adsorptive accumulation after the end of the injection period, and employing the lowest possible injection rate from the electronic micropipette of 24.5muLs-1. The practical detection limit is 5 nM for nickel and 2 nM for cobalt. Comparison is made with batch injection analysis with anodic stripping voltammetry and the merits of the technique relative to continuous flow-through methods are assessed.