Determination of transition metals in human hair by high-performance liquid chromatography using sodium hexadecane-sulfonate coated columns

A chromatographic method for the determination of transition metals in huma n hair samples is described. The method involves the separation of Cu, Pb, Zn, Ni, Co, Cd and Mn in a C18 column coated with sodium hexadecane-sulfona te (SHS) and spectrophotometric detection (520 nm) after post-column reacti on of the eluted metals with 4-(2-pyridylazo)-resorcinol (PAR). The eluent was a 100 mM tartrate solution adjusted to pH 3.1 with a 2 M sodium hydroxi de solution (flow-rate = 1.0 mi min(-1)). A good separation of the eluted m etals (specially for Cu/Pb and Zn/Ni) has been achieved. The detection limi ts, expressed as mu g l(-1), were 2.2 (Cu), 8.0 (Pb), 2.8 (Zn), 1.5 (Ni), 1 .5 (Co), 12.0 (Cd), and 1.4 (Mn). A microwave-assisted closed vessel acid d igestion procedure with HNO3 + HClO4 (4 + 1 ml) was used for the hair sampl es solubilisation. Nineteen hair samples were analysed with the proposed me thod. The results were in good agreement with those obtained by atomic abso rption spectrometry (AAS). (C) 1999 Elsevier Science B.V. All rights reserv ed.