Determination of antimony in urine by solvent extraction and electrothermal atomization atomic absorption spectrometry for the biological monitoring of occupational exposure

Abstract

A sensitive method for the determination of antimony in urine using solvent extraction and electrothermal atomic absorption spectrometry (ETAAS) is described. Urine samples were acidified with hydrochloric acid, and then heated in order to reduce antimony(v) to antimony(III). The antimony present was chelated with ammonium N-nitrosophenyl hydroxylamine (Cupferron) and then extracted into isobutyl methyl ketone. The organic layer was analysed by ETAAS. The effect of pH on the extraction efficiency of the procedure was investigated. The detection limit for the method was 0.69 µg l^–1. The coefficient of variation for within-run precision was 8.2% and between-run precision was 8.9%. The analytical recovery of antimony from urine was 103%± 11% at 5.16 µg l^–1.

The method was validated using urine samples collected from three industrial groups. The range of antimony levels found in the groups were as follows: control subjects = 0.18–2.16 µg l^–1; refinery workers = 0.08–32.6 µg l^–1; chemical manufacturers = 0.1–36.1 µg l^–1, and battery manufacturers = 1.5–149.2 µg l^–1. The method is particularly suited to the biological monitoring of occupationally exposed workers as it is robust and about 40 samples can be analysed within a normal working day.