INVESTIGATION OF NUCLEOSIDE AND NUCLEOTIDE DERIVATIVES BY PLASMA DESORPTION MASS-SPECTROMETRY

Molecular masses were determined and the dissociation of quasimolecular ions of two nucleoside triphosphates as well as of a number of nucleosides and nucleoside monophosphate analogs with potential antiviral activity were studied by plasma desorption mass spectrometry with ionization by Cf-252 fission fragments. The specimen was in a nitrocellulose layer on solid support. As a rule, the mass spectra of positive polarity display a quasimolecular ion MH(+), and also intense peaks corresponding to different bond breaks in the molecules. The most typical breaks occur in the glycoside part of the molecule, with charge stabilization within the heterocyrclic base. Mass spectra of negative polarity represent more intense peaks of MH(-) and BH- ions as well as less intense peaks of molecule fragments. The ammonium salts of the nucleotides give the most accurate mass spectra Nucleoside triphosphates have to be converted to pyridinium derivatives.