FORMATION AND COLLISION-INDUCED DISSOCIATION OF ADDUCT IONS [MATRIX+C](+) (C=LI, NA, CS AND NH4) PRODUCED UNDER FAST-ATOM-BOMBARDMENT CONDITIONS

The formation of adduct ions of matrices B with organic/metallic cations C+, [B + C](+) (C = Li, Na, Cs and NH4), under fast atom bombardment (FAB) conditions has been examined. The cation affinity (CA) for various matrix materials, glycerol, thioglycerol, dithiothreitol, m-nitrobenzylalcohol and diethanolamine, was evaluated from the positive-ion FAB mass spectra obtained for the salts LiCl, NaCl, CsCl or NH4Cl added to matrix B. The order of the CA of matrices for relatively small cations Lit and Na+ was in accordance with that of the proton affinity (PA) of the matrices used. The collision-induced dissociation (CID) spectra of [B + H](+) and [B + C](+) ions have been obtained. The PA differences between matrix B and ammonia (NH3) molecules were roughly estimated from the CID spectra of [B + NH4](+) ions. The CID spectra of [B + C](+) ions, which have different dissociation windows from [B + H](+) ions, were analyzed by proposing multidentate-binding structures of the adduct ions. Some dissociations of [B + C](+) ions could be explained by charge-remote fragmentations. The results obtained suggest that the binding energy for the coordination complex (B... C+) can be evaluated from the CID patterns.