SPECIATION OF ARSENIC COMPOUNDS IN URINE BY LC-ICP MS

The method validation for the speciation of five arsenic species in ur ine samples by liquid chromatography hyphenated to inductively coupled plasma mass spectrometry is described. Arsenic species which are iden tified and quantified in urine samples are the anions cationic arsenic (III), arsenic(V), monomethylarsonic acid and dimethylarsinic acid, an d the cationic arsenobetaine. Detection limits were obtained in the ra nge 0.3-0.4 mu g As l(-1) while the repeatability was in the range 3-4 % (RSD) for concentrations above five times the detection limit. Urine samples could be analysed directly after a tenfold dilution step, Ars enic compound concentrations were determined in urine samples from a v olunteer who consumed a portion of tuna fish high in arsenobetaine. It was found that arsenobetaine was excreted rapidly via the urine with maximum concentrations after 12 h. Nearly complete arsenobetaine excre tion was reached after 48 h. Background levels of arsenic compounds we re determined in 61 urine samples from non-exposed inhabitants of The Netherlands. (C) 1998 John Whey & Sons, Ltd.