A new strategy for preparation of hair slurries using cryogenic grinding and water-soluble tertiary-amines medium

The investigation of trace metal contents in hair can be used as an index o f exposure to potentially toxic elements. Direct determination of Cd, Cu an d Pb in slurries of hair samples was investigated using an atomic absorptio n spectrometer with Zeeman-effect background correction. The samples were p ulverized in a freezer/mill for 13 min, and hair slurries with 1.0 g l(-1) for the determination of Cu and Pb, and 5.0 g l(-1) for the determination o f Cd, respectively, were prepared in three different media: 0.1% v/v Triton X-100, 0.14 mol l(-1) HNO3, and 0.1% v/v of CFA-C, a mixture of tertiary a mines. The easiest way to manipulate the hair samples was in CFA-C medium. The optimum pyrolysis and atomization temperatures were established with ha ir sample slurries spiked with 10 mug l(-1) Cd2+, 30 mug l(-1) Pb2+, and 10 mug l(-1) Cu2+. For Cd and Pb, Pd was used as a chemical modifier, and for Cu no modifier was needed, The analyte addition technique was used for qua ntification of Cd, Cu, and Pb in hair sample slurries. A reference material (GBW076901) was analyzed, and a paired t-test showed that the results for all elements obtained with the proposed slurry sampling procedure were in a greement at a 95% confidence level with the certified values. The cryogenic grinding was an effective strategy to efficiently pulverize hair samples. (C) 2001 Elsevier Science B.V. All rights reserved.