LOW-ENERGY TANDEM MASS-SPECTROMETRY OF DEOXYNUCLEOSIDE ADDUCTS OF POLYCYCLIC AROMATIC HYDROCARBON DIHYDRODIOL-EPOXIDES

The use of fast-atom bombardment ionization-tandem mass spectrometry a pproaches, with collision energies on the order of 30-50 eV, was devel oped for the analysis of low picomole quantities of polycyclic aromati c hydrocarbon dihydrodiol-epoxide deoxynucleoside adducts. This strate gy combines three experimental techniques: (1) product ion scans, (2) constant neutral loss scans, and (3) precursor ion scans. Product ion scans of the protonated molecule or the BH: ion that results from loss of the deoxyribose were dominated by fragments associated with cleava ge of the sigma bond between the dihydrodiol-epoxide moiety and the nu cleobase. Constant neutral loss scans were based upon the loss of deox yribose (116 u) or the combined loss of the deoxynucleoside, water, an d carbon monoxide (313 u); precursor ion scans utilized the latter fra gment. The formation of trimethylsilyl derivatives increased the sensi tivity of analysis, which allowed the simultaneous detection of DNA ad ducts in a mixture.