Square-wave adsorptive stripping voltammetry at glassy carbon electrode for selective determination of manganese. Application to some industrial samples

A new method to determine manganese by voltammetry after controlled adsorptive accumulation of the manganese-ammonium-acetate at the glassy carbon electrode is described. The manganese complex gives well-defined voltammetric peak at pH 4.0 and 9.0. Cathodic stripping voltammetry combined with the Osteryoung square-wave mode at the glassy carbon electrode gave rise to both sensitivity and selectivity of the determination of manganese in some industrial samples. The method offers enhanced sensitivity in comparison to analogous measurements presented in the literature. The detection limit with 5 min accumulation is 0.022 mu g l(-1). Simultaneous determination of manganese in presence of Cu(II), Pb(II) and Zn(II) could be easily done using anodic stripping voltammetry at pH 4.0. Calibration plots are constructed and the method was checked with the aid of standard industrial reference samples giving values of standard deviations between 1.2 and 1.8. (C) 1998 Elsevier Science B.V. All rights reserved.