Potential of high performance liquid chromatography coupled to flow injection hydride generation atomic absorption spectrometry for the speciation ofinorganic and organic antimony compounds

This investigation was undertaken to elucidate the potential of high-perfor mance liquid chromatography coupled to a hydride generation system connecte d to an atomic absorption spectrometer (HPLC-HG-AAS) as an element specific detector for the speciation of Sb(iii), Sb(v) and trimethylantimony dichlo ride (TMSbCl2). HG parameters were optimised specifically with regard to th e Sb-species and yielded distinctly different optima for Sb(III) and Sb(V) as regards concentrations of NaBH4 and HCl. HCl (0.5% w/v) and of NaBH4 (0. 6% w/v) proved to be a good compromise for optimum sensitivity for all Sb s pecies. After optimisation, signals for Sb(v) were still two times lower th an for Sb(III) and TMSbCl2. Among the five anion exchange columns tested, t he Dionex AS14 provided best results for the separation of Sb(V) and Sb(III ) with 1.25 mM EDTA at pH 4.7. The ION-120 column was used to separate TMSb Cl2 and Sb(V) with 2 mM NH4HCO3 and 1 mM tartaric acid at pH 8.5. When sepa rating the three Sb-species in a single chromatographic run, sharp peaks fo r Sb(V) and Sb(III), but a very broad peak for TMSbCl2, were obtained. In a ll chromatographic separations the peaks could be baseline separated. Calib ration curves were linear between 2 and at least 100 mu g l(-1). Detection limits of 0.4, 0.7, and 1.0 mu g l(-1) for TMSbCl2, Sb(III), and Sb(V) were obtained.