Matrix-assisted laser desorption ionization and time-of-flight mass spectrometry for the sensitive determination of arylamide–deoxynucleoside adducts Original Research Article

Matrix-assisted laser desorption/ionization (MALDI) and time-of-flight mass spectrometry (TOFMS) are tested for the determination of arylamide adducts of deoxyguanosine. Fifteen matrices were tested for the sensitive determination of N-(guanosin-8-yl)-2-acetylaminofluorene, (dG-C8-AAF), a compound whose structure is representative of carcinogen–DNA adducts formed by nitroaromatic and arylamine carcinogens. Eight matrices allow adduct detection when 560 fmole or less is introduced into the TOFMS. Two matrices, α-cyano-4-hydroxycinnamic acid (CHCA) and mercaptobenzothiazole (MBT), promoted adduct detection when 56 fmol or less of adduct is introduced into the TOFMS. The other seven matrices did not permit dG-C8-AAF adduct detection at the low pmol level. In all determinations the limit of detection (LOD) is based on the nucleic acid–arylamide, BH+2 fragment ion formed by the cleavage of the glycosidic bond. The relation between matrix structure and the mechanism of analyte ionization is discussed as well.