Determination of metals in multicomponent system by differential pulse and alternating current anodic stripping voltammetry

A combination of sensitive and selective voltammetric methods, namely differential pulse (DPASV) and fundamental and second harmonic alternating current anodic stripping voltammetry (ACASV) were found to be very suitable techniques for the simultaneous determination of metal species having half-wave potentials close to one another. The simultaneous determination of traces of CuII, BIII, SbIII, PbII, CdII and SnII is described using 0.1 M HCl as the supporting electrolyte with the subsequent addition of 0.02 M EDTA or 1.0 M NaOH (for the analysis of CuII, SbIII and SnII, respectively). A semistationary mercury electrode (long lasting sessile drop mercury electrode) was used as the working electrode. A saturated calomel electrode (SCE) and a platinum electrode were used as the reference and auxiliary electrodes, respectively. The analytical procedure was verified with the analysis of standard reference material NBS-SRM 631 Spectrographic Zinc Spelter LV1. Precision and accuracy, expressed as relative standard deviation and relative error, respectively, were 3 to 5%, while the detection limits were of the order of 10-8 to 10-10 M in the case of element examined.