DIFFERENTIATION OF ISOMERIC C8-SUBSTITUTED AND N2-DEOXYGUANOSINE ADDUCTS OF 2-ACETYLAMINOFLUORENE BY FAST-ATOM-BOMBARDMENT AND TANDEM MASS-SPECTROMETRY

Product-ion studies of source-produced ions corresponding to acetylate d and nonacetylated N2- and C8-substituted aminofluorene adducts of de oxyguanosine were conducted to identify specific fragmentation pathway s differentiating the isomers and to determine the influence of the ac etyl group on the fragmentation of the arylamide modified deoxyguanosi ne adducts. The collision-induced dissociation spectra of the BH2+ ion and other significant source-produced ions showed no evidence to sugg est that ketene loss (deacetylation) resulted in significant alteratio n of the structure of the adducts. However, other significant ion form ation processes, particularly loss of water from the N2-substituted ar ylamide did appear to require rearrangement, likely involving bond for mation between the carcinogen moiety (acetyl group) and the N1 or N2 p osition of the guanine base. The combined loss of ketene and water con stitute a fragmentation pattern specific for the N2-arylamide, 3-(deox yguanosin-N2-yl)-2-acetylaminofluorene.