DEMETHYLATION OF TRIMETHYLANTIMONY SPECIES IN AQUEOUS-SOLUTION DURINGANALYSIS BY HYDRIDE GENERATION GAS-CHROMATOGRAPHY WITH AAS AND ICP MSDETECTION

The method of hydride generation for the speciation of antimony compou nds was examined with respect to the problem of molecular 'rearrangeme nt'. Specifically, demethylation of trimethylstilbine during the analy sis of trimethylantimony dichloride (Me3SbCl2) was studied, Previously published observations that enhanced demethylation takes place as a r esult of inadequate preconditioning of the analytical apparatus were f ound to be not reproducible, However, demethylation was enhanced as th e pH decreased when using two different analytical methods: semi-conti nuous how hydride generation-gas chromatography-atomic absorption spec trometry (HG-GC-AAS), and batch-type hydride generation-gas chromatogr aphy-inductively coupled mass spectrometry (HG-GC-ICP MS). Application s of the hydride generation method to environmental samples revealed d ifferences in analytical results at high and low pH, and enhanced deme thylation taking place because of the matrix in a fungal extract sampl e, The authors recommend that researchers using the method of hydride generation for antimony compounds carefully test the reaction conditio ns with standard compounds and use the method of standard addition onl y. (C) 1998 John Wiley & Sons, Ltd.