MASS-SPECTROMETRIC STUDY OF 8-AZAXANTHINE DERIVATIVES

N-3 and N-9 derivatives of 8-azaxanthine have been studied using elect ron impact mass spectrometry. Mass-analyzed metastable ion kinetic ene rgy, linked scan at the constant B/E, collision-induced dissociation m ethods, as well as high-resolution measurements have been used for eva luation of complete fragmentation schemes. Two fragmentation pathways of 8-azaxanthine skeleton begin by the elimination of CH3NCO or N-2 mo lecule. The primary elimination of nitrogen molecules is characteristi c difference in fragmentation routes of 8-azaxanthines in comparison t o purine. Another pathway leads to fragmentation of the N-3 and N-9 su bstituents.