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

The formation of adduct ions of matrices B with organic/metallic catio ns C+, [B + C](+) (C = Li, Na, Cs and NH4), under fast atom bombardmen t (FAB) conditions has been examined. The cation affinity (CA) for var ious matrix materials, glycerol, thioglycerol, dithiothreitol, m-nitro benzylalcohol and diethanolamine, was evaluated from the positive-ion FAB mass spectra obtained for the salts LiCl, NaCl, CsCl or NH4Cl adde d to matrix B. The order of the CA of matrices for relatively small ca tions Lit and Na+ was in accordance with that of the proton affinity ( PA) of the matrices used. The collision-induced dissociation (CID) spe ctra of [B + H](+) and [B + C](+) ions have been obtained. The PA diff erences between matrix B and ammonia (NH3) molecules were roughly esti mated 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 expla ined by charge-remote fragmentations. The results obtained suggest tha t the binding energy for the coordination complex (B... C+) can be eva luated from the CID patterns.