Determination of lead in hair and its segmental analysis by solid sampling electrothermal atomic absorption spectrometry

Complete text of publication follows. A rapid and practical solid sampling electrothermal atomic absorption spectrometric method was described for the determination of lead in scalp hair. Using certified reference hair samples, the effects of pyrolysis and atomization temperatures, the amounts of sample and modifier (Pd/Mg), auxiliary digesting agents (hydrogen per oxide and nitric acid), surfactant (Triton X-100) on the recovery of lead were investigated. Hair samples were washed with distilled water, acetone and again distilled water. The samples were dried at 75 deg C and inserted on the platform typically as 0.1 to 0.5 mg. Applying a 500 deg C of pyrolysis temperature and a 1800 deg C of atomization temperature as well as without adding any modifier, nitric acid/hydrogen peroxide and Triton X-100, quantitative recoveries (>90%) were obtained using aqueous standards. Since solid sampling needs very low amounts of samples, heterogen distribution of analyte in a sample could be determined. This property of solid sampling was benefited to make segmental analyses along one or a few scalp hair strands For this purpose, about 0.5 cm of pieces were cut along the one or a few close strands and analyzed by solid sampling. By considering that hair grows 1 cm per month, the change of lead along the hair strands were related to its uptake date and amount.