Application of double focusing sector field ICP-MS for multielemental characterization of human hair and nails. Part I. Analytical methodology

The capabilities of double focusing sector field inductively coupled plasma mass spectrometry (ICP-SMS) for the determination of 71 elements in hair a nd nails were studied. A microwave-assisted digestion procedure with nitric acid and hydrogen peroxide as well as direct sampling of the nails by lase r ablation (LA) have been tested. Examples of spectral interferences are gi ven and different correction procedures are discussed. Method detection lim its below ng g-l were obtained for 39 elements investigated by using high-p urity reagents and by taking special care to prevent contamination during p reparation. However, these detection limits were insufficient for detection of some platinum group elements in the majority of the samples. The accura cy of the analytical procedure was estimated by analysis of the GBW07601 ce rtified reference material as well as by participation in an interlaborator y comparison program. The reproducibility was assessed from replicate analy sis (including sample preparation) and was found to be, as average values f or all elements, 9-10% R.S.D. and 18-19% R.S.D. for hair and nails, respect ively. Contribution from exogenous deposition was evaluated by analyzing sa mples before and after washing, as well as by studying spatial element dist ribution along hair and nails. It was found that even after sample washing, many elements are enriched in the surface of the nail. (C) 2000 Elsevier S cience B.V. All rights reserved.