Method for cadmium and lead longitudinal profiles determination in hair by solid sampling graphite furnace atomic absorption spectrometry

Abstract

This paper describes methods for the direct determination of Cd and Pb in hair segments (c.a. 5 mm, ∼80 μg) by solid sampling graphite furnace atomic absorption spectrometry, becoming possible longitudinal profiles in a single strand of hair. To distinguish endogenous and exogenous content, strands of hair were washed by using two different procedures: IAEA protocol (acetone + water + acetone) and the combination of IAEA protocol with HCl washing (acetone + water + acetone + 0.1 mol l⁻¹ HCl). The concentration of Cd and Pb increased from the root until the tip of hair washed according to IAEA protocol. However, when the strand of hair was washed using the combination of IAEA protocol and 0.1 mol l⁻¹ HCl, Cd concentrations decreased in all segments, and Pb concentrations decreased drastically near to the root (5 to 12 mm) and was systematically higher in the end. The proposed method showed to be useful to assess the temporal variation to Cd and Pb exposure and can be used for toxicological and environmental investigations. The limits of detection were 2.8 ng g⁻¹ for Cd and 40 ng g⁻¹ for Pb. The characteristic masses based on integrated absorbance were 2.4 pg for Cd and 22 pg for Pb.