Determination of sub-μg 1-1 concentrations of copper by anodic stripping voltammetry at the gold electrode

A rotating disc gold electrode is used for the determination of copper in mu g l(-1) and sub-mu g l(-1) concentrations without removal of oxygen by the method of subtractive anodic stripping voltammetry (SASV). The detection limit for a 90 s electrodeposition is 0.2 nM. The reduction and stripping of copper on gold under the SASV conditions are underpotential deposition/dissolution phenomena. A uniformly distributed submonolayer of copper, occupying 0.01-5% of the real surface of the electrode, is formed. Linearity in calibration plot is obtained up to 5% electrode coverage; in terms of the experimental parameters of the deposition step (rate of rotation and time of electrolysis), this condition for linearity is C(Cu2+)N(1/2)t(d) less than or equal to 7 x 10(5) nM rpm(1/2) s. The bulk and underpotential deposition of Cu2+ have been characterized in the supporting electrolyte used (10 mM HNO3 and 10 mM NaCl). The analysis of copper in drinking and in sea waters has been performed. (C) 1999 Elsevier Science B.V. All rights reserved.