Bone-lead analysis: development of analytical methodology for milligram samples

Abstract

A graphite platform-in-furnace atomic absorption spectrometric (GFAAS) method for determining micrograms/g levels of Pb in 10-20 mg cortical and trabecular primate bone samples is described. The GFAAS method is based on an ambient temperature nitric acid digestion of the sample, matrix modification with palladium nitrate, stabilized temperature platform furnace atomization, and a systematic evaluation of the temperature program of the atomizer. The method of standard additions is mandatory. The detection limit (3 standard deviations of the blank) is 0.19 micrograms Pb/g dry weight for a 10-mg sample taken up in a 1-mL volume. Data are presented on the degree of accuracy and precision. The accuracy of the proposed GFAAS method has been assessed using the IAEA bone reference material, H-5, and by comparing the values obtained in a bone sample with an isotope dilution mass spectrometric (IDMS) procedure. The GFAAS method can be applied to the determination of Pb in 10-20 mg bone samples and for concentrations which are > or = 10 x detection limit. The method is simple, fast, and contamination-free since the entire operation from weighing to GFAAS measurement is carried out in the same centrifuge tube. The method has been applied to the determination of total-Pb in some adult and fetal primate cortical and trabecular bone specimens.