DETERMINATION OF ANTIMONY IN URINE BY SOLVENT-EXTRACTION AND ELECTROTHERMAL ATOMIZATION ATOMIC-ABSORPTION SPECTROMETRY FOR THE BIOLOGICAL MONITORING OF OCCUPATIONAL EXPOSURE

A sensitive method for the determination of antimony in urine using so lvent extraction and electrothermal atomic absorption spectrometry (ET AAS) 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 hydroxyla mine (Cupferron) and then extracted into isobutyl methyl ketone. The o rganic layer was analysed by ETTAAS. The effect of pH on the extractio n efficiency of the procedure was investigated. The detection limit fo r the method was 0.69 mu g l(-1). The coefficient of variation for wit hin-run precision was 8.2% and between-run precision was 8.9%, The ana lytical recovery of antimony from urine was 103% +/- 11% at 5.16 pg l( -1). The method was validated using urine samples collected from three industrial groups. The range of antimony levels found in the groups m ere as follows: control subjects = 0.18-2.16 mu g l(-1); refinery work ers = 0.08-32.6 mu g l(-1); chemical manufacturers = 0.1-36.1 mu g l(- 1), and battery manufacturers = 1.5-149.2 mu g l(-1). The method is pa rticularly suited to the biological monitoring of occupationally expos ed workers as it is robust and about 40 samples can be analysed within a normal working day.