Factors affecting the simultaneous determination of cooper, lead, cadmium and zinc concentrations in human head hair using different pulse anodic stripping voltametry method.

Abstract

Conditions of analyses of copper, lead, cadmium and zinc content in human hair using differential pulse anodic stripping voltammetry (DPASV) and hanging mercury drop electrode (HMDE) have been established. Sample digestion using the mixture HC1; H2O2:HNO3 in the ratio 2:1:40 by volume gave the best wet-ashing procedure. The peak currents and peak potentials of zinc, cadmium and lead, copper were maximum at pH 6-7 and 1-3 respectively, when excess H2O2 was eliminated with subsequent addition of hydroxyamine hydrochloride. Matrix concentration effects were minimized by digesting weights not exceeding 50 mg per sample. The effect of selenium (IV) was negligible and was ignored. The detection limit of 0.0036 ng/cm3 for Cd+2 was obtained while the values for zinc, lead and copper were 0.0230, 0.0287 and 0.0269 ng/cm3 respectively, at the 95% confidence limit. The observed DPASV conditions of analysis of these metals are useful for routine determination of the metals in human hair and should complement the conventional flame atomic absorption spectrophoto-metry methods