Analysis of aluminium in serum and urine for the biomonitoring of occupational exposure

A reliable and sensitive graphite furnace atomic absorption spectrometry (GFAAS) method with Zeeman background correction was developed for the analysis of aluminium in serum and urine in the biological monitoring of aluminium exposure. The method is based on platform atomisation in pyrolytically coated graphite tubes after fourfold dilution with nitric acid. For serum analysis, a matrix matched standard curve is prepared and for urine the method of standard additions is used. The within-run imprecision (C.V.) for serum and urine was 3% and 5%, and the between-day imprecision, 6% and 7.2%, at a concentration level of 4.0 μmol/l. The between-day imprecision for urinary aluminium was 15.7% at a concentration level of 0.24 μmol/l. The detection limits were 0.02 μmol/l for serum and 0.07 μmol/l for urine. During 1 year of participation in TEQAS external quality assessment scheme of the Robens Institute for Health and Safety (Guildford, UK) for serum aluminium the maximum cumulative performance score was achieved. For urinary aluminium a certificate in the external quality control scheme of the German Society of Occupational Medicine was obtained. The mean concentration of aluminium in a non-exposed population, who did not use antacid drugs, was 0.06 μmol/l (S.D. 0.03, range 0.02–0.13, n = 21) in serum, and 0.33 μmol/l (S.D. 0.18, range 0.07–0.82, n = 44) in urine. The upper reference limit for aluminium in a healthy, non-exposed population was estimated to be 0.1 μmol/l in serum and 0.6 μmol/l in urine.