Determination of trace amounts of copper(II) by adsorptive stripping voltammetry of its complex with pyrogallol red

A sensitive and selective procedure is presented for the voltammetric determination of copper. The procedure involves an adsorptive accumulation of copper pyrogallol red on a hanging mercury drop electrode, followed by a stripping voltammetric measurement of reduction current of adsorbed complex at -0.2 V (vs. Ag/AgCl). The optimum conditions for the analysis of copper include pH (3.0-4.5), 20 mu M pyrogallol red and an accumulation potential of -0.1 V (vs. Ag/AgCl). The peak current is proportional to the concentration of copper over the range 0.4-60 ng ml(-1) with a detection limit of 0.07 ng ml(-1) with an accumulation time of 60 s, The method was applied to the determination of copper in some analytical grade salts and also in cow's liver tissue. (C) 1999 Elsevier Science B.V. All rights reserved.