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In cases of arsenic poisoning, the distribution of arsenic along the length of a hair can be used to distinguish between chronic and acute exposure. Individual 5-mm segments of a hair were analyzed for their arsenic content by solid sampling graphite furnace atomic absorption spectrophotometry with a mixed Pd-Mg(NO3)2 matrix modifier. Results obtained using arsenic calibration solutions and standard additions to uncontaminated hairs are analytically indistinguishable, allowing aqueous standards to be used for hair analysis. The characteristic mass is 24 pg, and the 3 sigma detection limit is approximately 10 pg. Results obtained for hairs from two victims of arsenic poisoning are in good agreement with those obtained using neutron activation analysis.

Methods of extraction of gunshot residue (GSR) swabs for determination of antimony (Sb), barium (Ba), and lead (Pb) by flameless atomic absorption spectrophotometry (AAS) have been studied. Optimum extraction parameters were determined using recovery studies of Sb, Ba, and Pb added to swabs at amounts representative of actual GSR and handblank levels. Two difficulties with most extraction-AAS procedures are incomplete extraction of Sb and incorrect Ba results arising from improper matching of sample and standard matrices before AAS determinations. Utilization of standards made by spiking analyte elements on swabs and extraction along with samples by an efficient procedure minimizes errors in Sb, Ba, and Pb determination.

Inductively coupled plasma-atomic emission spectrometry (ICP-AES) was compared with atomic absorption spectrophotometry (AAS) for barium determination in gunshot residue (GSR) collection swabs. Lack of interferences by common swab extract constituents, a wide linear dynamic range, and good precision and accuracy of ICP-AES make it superior to AAS for barium determination in GSR swab extracts.