Selective determination of Sb(III) by gas chromatography quartz furnace atomic absorption spectrometry after derivatization with triphenylmagnesium bromide

A method is described for the selective determination of Sb(III) in the presence of Sb(V) by capillary column gas chromatography-quartz furnace atomic absorption spectrometry. Sb(III) is complexed with pyrrolidinedithiocarbamate in a medium buffered with acetic acid-acetate at pH 4.5 and extracted into hexane; once extracted, Sb(III) is derivatized into a volatile gas chromatographable species, triphenylstibine, by Grignard reaction with phenylmagnesium bromide. A cool injection programmed-temperature vaporization injector (CTI) was used. Parameters affecting the extraction and derivatization reactions, as well as the atomization temperature in the quartz furnace and the maximum volume of organic phase that can be injected in the CTI, were optimized. The method was applied to the determination of Sb(III) in spiked tap water.