The chemical ionization mass spectra of a series of tricyclic flavanoid compounds
have been examined using isobutane and hydrogen as reagent gases and the fragmen-
tation modes have been correlated systematically in terms of structure. The technique
produces simple fragmentation patterns and abundant metastable ions. The use of
deuterium as reagent gas reveals the influence of extraneous water on the spectra and
facilitates the interpretation of the fragmentation pathways. The fragment ions appear
to arise from isomeric progenitors protonated at different sites in the molecules.
