MATRIX-ASSISTED LASER-DESORPTION IONIZATION AND TIME-OF-FLIGHT MASS-SPECTROMETRY FOR THE SENSITIVE DETERMINATION OF ARYLAMIDE-DEOXYNUCLEOSIDE ADDUCTS

Matrix-assisted laser desorption/ionization (MALDI) and time-of-flight mass spectrometry (TOFMS) are tested for the determination of arylami de adducts of deoxyguanosine. Fifteen matrices were tested for the sen sitive 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 matri ces allow adduct detection when 560 fmole or less is introduced into t he TOFMS. Two matrices, alpha-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 a ll determinations the limit of detection (LOD) is based on the nucleic acid-arylamide, BH2+ fragment ion formed by the cleavage of the glyco sidic bond. The relation between matrix structure and the mechanism of analyte ionization is discussed as well. (C) 1998 Elsevier Science B. V.