Simultaneous Determination of Copper(II), Lead(II) and Zinc(II) at Bismuth Film Electrode by Multivariate Calibration

In this work, simultaneous determination of Cu(II), Pb(II) and Zn(II) ions at low concentration levels (ppb) by square wave anodic stripping voltammetry on a Bi(III) film electrode plated in situ at a glassy carbon electrode (GCE) is described. A chemometric approach was used to overcome the overlapping peaks of Cu(II) and Bi(III), the competition of the electrodeposited Cu and Bi for the surface of the GCE and the formation of Cu-Zn intermetallic compounds. The construction of the multivariate calibration models, based on partial least squares regression, allowed the simultaneous determination of Cu (in the concentration range 8.0 to 20.1 ppb), Pb (2.0 to 30.0 ppb) and Zn (29.7 to 90.4 ppb) with most of the prediction errors obtained in the external validation set for the three models lower than 16, 11 and 26%, respectively. Finally, this method was used for the determination of these trace metal ions in surface river water samples with satisfactory results [errors below 10, 5 and 32% for Cu(II), Pb(II) and Zn(II), respectively].