Axial distribution of arsenic in individual human hairs by solid sampling graphite furnace AAS

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.