Differentiation of isomeric 1-, 3- and 7-deazaadenosines by electron ionization mass spectrometry

The low and high resolution electron ionization mass spectra of 1-deazaadenosine, 3-deazaadenosine and 7-deazaadenosine are reported. Fragmentation pathways and ion structures are proposed with the aid of linked-scan, daughter-ion spectra. Results indicate that the N-3 position of the purine ring serves as an important acceptor site in fragmentation processes involving hydrogen transfer from the sugar to the base. A mixture analysis of the trimethylsilyl derivatives of adenosine, 1-, 3- and 7-deazaadenosine by combined gas chromatography/mass spectrometry is also described.