On‐line photodecomposition for the determination of antimony species

On‐line UV photooxidation by peroxodisulfate was coupled to ion chromatography hydride generation atomic fluorescence spectroscopy (IC‐UV‐HG‐AFS) for the speciation of inorganic antimony Sb(III) and Sb(V)] and methylated species. Several parameters (UV lamp, irradiation time and peroxodisulfate concentration) that greatly influence the sensitivity of these three antimony species were investigated in depth. Under optimized conditions, photodecomposition resulted in an improvement in methylantimony species sensitivity. Dilution in di‐ammonium tartrate medium was necessary in order to ensure short‐term stability of Sb(III) at the µg l^?1 concentration level. Furthermore, the efficiency of irradiation was strongly dependent on the chemical composition of the measured solution. Detection limits of 0.04 µg l^?1 for Sb(V), 0.03 µg l^?1 for Me₃SbCl₂ and 0.03 µg l^?1 for Sb(III) as well as repeatability and reproducibility better than 4 and 8% RSD, respectively, were obtained. The proposed methodology was applied for antimony speciation in terrestrial plant sample extracts. Copyright © 2005 John Wiley & Sons, Ltd.