EVALUATION OF LIQUID-CHROMATOGRAPHY THERMOSPRAY MASS-SPECTROMETRY IN THE DETERMINATION OF SOME PHENYLGLYCIDYL ETHER 2'-DEOXYNUCLEOSIDE ADDUCTS

The adducts formed between 2'-deoxyadenosine (dAdo), 2'-deoxycytidine (dCyd) and 2'-deoxyuridine (dUrd) and phenyl glycidyl ether (PGE) were analysed by HPLC and LC-thermospray (TSP)-MS. Good results were obtained on a 10 RP Select B column (12.5 cmx4 mm I.D.) using 0.1 M NH4OAc-CH3OH at a flow-rate of 0.8 ml/min. The mass spectra of the 2'-deoxynucleoside-PGE adducts, obtained under LC-TSP-MS conditions were all characterized by the presence of the protonated molecule [MH]+ and [BH+H]+ ions. The PGE-dCyd adduct underwent hydrolytic deamination to the corresponding PGE-dUrd adduct. There was an indication that this process of hydrolytic deamination also took place in the TSP interface. Localization of the alkylation site was possible in the PGE-dUrd adduct by the presence of an RDA rearrangement leading to a fragment ion at m/z 194. Preliminary sensitivity studies on PGE-dUrd showed a detection limit of 500 pg (signal-to-noise ratio = 2) in multiple ion monitoring at m/z 263 and 379.