BATCH INJECTION-ANALYSIS WITH ADSORPTIVE STRIPPING VOLTAMMETRY FOR THE DETERMINATION OF TRACES OF NICKEL AND COBALT

Square wave adsorptive stripping voltammetry (AdSV) in conjunction wit h the batch injection analysis technique has been investigated at merc ury thin-film electrodes, using analysis of nickel and cobalt ions wit h nioxime ligand as example, and injection of sample volumes of less t han or equal to 100 mu L. Experiments were conducted in a HEPES neutra l buffered medium, suitable for analysis of biological fluids. Sensiti vity is maximized by continuing the adsorptive accumulation after the end of the injection period, and employing the lowest possible injecti on rate from the electronic micropipette of 24.5 mu L s(-1). The pract ical detection limit is 5 nM for nickel and 2 nhl for cobalt. Comparis on is made with batch injection analysis with anodic stripping voltamm etry and the merits of the technique relative to continuous flow-throu gh methods are assessed.