DETERMINATION OF TRIBUTYLTIN OXIDE AND ITS DI-BUTYL AND MONOBUTYL METABOLITES IN URINE USING COMBINED GAS-CHROMATOGRAPHY ATOMIC-ABSORPTION SPECTROMETRY

The method described involves linked gas chromatography-atomic absorption spectrometry (GC-AAS), which is used to determine simultaneously tributyltin oxide (TBTO) and its dibutyl and monobutyl metabolites in urine. The compounds are extracted from urine using diethyl ether containing the chelating agent tropolone and are converted into the more volatile hydrides by sodium tetrahydroborate. These species are extracted into hexane and injected into the gas chromatograph, which is connected to the quartz tube of the AAS system via a heated transfer line. Mass spectrometry was used to confirm the detection of the three species. The detection limits for the system are 1-mu-g 1-1 for mono- and dibutyltin hydrides and 2-mu-g 1-1 for tributyltin hydride. The recoveries of the three species range from 94-107%. The method was used to investigate TBTO levels in workers occupationally exposed to TBTO-containing wood preservatives and in metabolic studies investigating the orally dermal absorption of TBTO in rats. No trace of TBTO or its metabolites was detected in any of the workers but absorption both orally and dermally was demonstrated in the rat studies.