Antimony speciation in environmental samples by using high-performance liquid chromatography coupled to inductively coupled plasma mass spectrometry

An analytical method based on the hyphenation of liquid chromatography and inductively coupled plasma mass spectrometry was developed and used for the speciation of antimony in environmental samples. The baseline separation of inorganic Sb(III) and Sb(V) was achieved by using a mobile phase of 2 mmol/l phthalic acid-5 mmol/l EDTA at pH 4.5 on a silica-based anion-exchange column (Synchropak Q300, 100 x 4.6 mm i.d.). The retention times were 164 and 260 s for Sb(V) and Sb(III), respectively. The calibration curves were linear over the range of 1.0 - 100 mu g/l for the investigated Sb species. The detection limits were 10 pg and 30 pg per 100 mu l sample for Sb(V) and Sb(III), respectively. The precision, evaluated by using the relative standard deviation (RSD) with a 5 mu g/l standard solution, was 2.4% and 4.3% (n=6) for Sb(V) and Sb(III), respectively. The detection limits achieved in the present work were sufficiently low to measure Sb species in environmental samples. The proposed method for the speciation of Sb was applied to the determination of Sb(V) and Sb(III) in tap-water and the aqueous extracts of airborne particulate matter. The results showed that for airborne particulate matter there are multiple Sb species.