Differentiation between isomeric phenylglycidyl ether adducts of 2 '-deoxyguanosine and 2 '-deoxyguanosine-5 '-monophosphate using liquid chromatography/electrospray tandem mass spectrometry

The reaction between phenylglycidyl ether and 2'-deoxyguanosine or 2'-deoxy guanosine-5'-monophosphate yields a variety of different nucleoside and nuc leotide adducts, The corresponding mixtures were analyzed by liquid chromat ography/electrospray tandem mass spectrometry and the product ion spectra o f the different isomers are discussed using the correct cone voltage and co llision energy. The latter were selected by looking at the energy-resolved spectra, From these data the formation of N7 and N2 isomers was proposed. H owever, detailed MMR analysis of the latter proved this isomer to be the N- 1-alkylated adduct, 2'-Deoxyguanosine-5'-monophosphate was alkylated by phe nylglycidyl ether at the 5'-phosphate position. If the nucleotide base moie ty was alkylated, the corresponding tandem mass spectrometric data strongly suggested alkylation of N7, In the case of bis-PGE-dGMP adduct, evidence w as found for simultaneous 5'-phosphate and N7-alkylation, Copyright (C) 199 9 John Wiley & Sons, Ltd.