LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY WITH COLLISION-INDUCED DISSOCIATION OF CONJUGATED METABOLITES OF BENZO[A]PYRENE

Benzo[a]pyrene (BP) metabolites conjugated with glutathione, cysteine- glycine, cysteine, N-acetylcysteine, and sulfuric and glucuronic acids have been studied by microcolumn liquid chromatography-electrospray m ass spectrometry with collision-induced dissociation (CID) on a hybrid double focusing magnetic sector-orthogonal. time-of-flight tandem mas s spectrometer equipped with a focal plane array detector. Negative-io n electrospray mass spectra of the conjugated BP metabolites showed st rong [M - H](-) ions. When the array detector was used, spectra were o btained from femtomoles of sample infused at mass resolutions of 5000 (full width at half maximum). Cone voltage fragmentation spectra show [M - H](-) ions and fragment ions indicative of the BP moiety and/or t he conjugating group. Linked scan CID spectra at constant B/E were fou nd to contain structurally informative product ions from infusion of a s little as 1 pmol of sample. CID spectra were also recorded by using the double focusing sectors for precursor ion selection and the orthog onal time-of-flight analyzer for product ion mass separation. The meth od was applied to the analysis of conjugated BP metabolites in the uri ne of germ-free rats given a single intraperitoneal dose of BP. (C) 19 97 American Society for Mass Spectrometry