Urinary antimony speciation by HPLC-ICP-MS

This is the first study to report on the determination of Sb species in uri ne. To this end, HPLC was coupled online to an ICP-MS instrument using ultr asonic nebulization (USN) or hydride generation (HG) for sample introductio n into the ICP-MS. The high chloride concentration in urine seriously hampe red the chromatographic separation of Sb(v) and Sb(III) on the Dionex AS14 anion exchange column. Distinct signal suppression, shifting of retention t imes and severe peak broadening did not allow the application to urine samp les. Progress to avoid these problems in HPLC-USN-ICP-MS could be made by e mploying a Hamilton PRP-X100 anion;exchange column. However, Na eluting in the void volume of the column gave rise to a Na-induced peak overlapping wi th the Sb(v) signal when USN was used to aspirate the HPLC eluents into the plasma. Therefore, a HG system was placed between the HPLC and ICP-MS inst rumentation to overcome this dilemma. Thus, Sb(v) and Sb(III) were separate d in urine with the PRP-X100 column using 20 mM EDTA at pH 4.7 as the mobil e phase. Similarly, an ION-120 anion-exchange column was employed to separa te trimethylantimony dichloride (TMSbCl2) and Sb(v) with a mobile phase con taining 2 mM NH4HCO3 and 1 mM tartaric acid at pH 8.5. Detection limits of 20 ng 1(-1), 12 ng 1(-1) and 8 ng 1(-1) for Sb(v), TMSbCl2 and Sb(III), res pectively, could be established in a 1 + 2 diluted urine matrix. The develo ped HPLC-HG-ICP-MS method was applied to the speciation of Sb in the urine of occupationally exposed and nan-exposed subjects. Additionally, two lyoph ilised urine reference materials were investigated. Sb(v) was by far the pr edominant Sb species, followed by TMSbCl2. Only ultratraces of Sb(III), if any detectable, could be found. The sum of the concentrations of Sb(v), Sb( III) and TMSbCl2 in urine samples ranged between 51 and 78% of their total Sb concentrations.