The fast atom bombardment mass spectra of some N-substituted pyrimidinium salts

Abstract

The fast atom bombardment mass spectra of selected 1,2-dihydro-1,3-disubstituted-2-oxo-pyrimidinium salts are presented. Loss of N-substituents from the solute cation is the principal fragmentation observed in the positive ion spectra. Several concentration dependent features of the spectra are identified; these are thought to result from the interaction of the solute cation with bombardment-induced matrix fragments. Cluster ions are observed in both positive and negative ion spectra. In a mixed solute system cluster ions resulting from extensive cation and anion mixing are observed; the concentration dependence of these mixed cluster ion peaks can be approximately described in terms of conventional solution equilibria.