CF-252 PLASMA DESORPTION MASS-SPECTROMETRY OF QUINOLINIUM SALTS AND METHOD OF ESTIMATION OF THEIR INTERMOLECULAR INTERACTIONS WITH PHOSPHOLIPIDS

Using Cf-252 plasma desorption mass spectrometry, the fragmentation of 1-phenyl-2(p-aminostyryl)quinolinium and 1-phenyl-2(p-aminostyryl)ben zo(f)quinolinium derivatives, with various substituents at the amino n itrogen, was studied. With plasma desorption ionization, the fragmenta tion features of the compounds studied are mainly determined by the na ture of the N',N '' substituents. The behaviour of some quinolinium de rivatives in the presence of lecithin, a basic component of the phosph olipid fraction of cell membranes, was investigated. For the benzo(f)q uinolinium derivative, the analysis of changes in the mass spectra ind icates a strong interaction between these substances, leading to the f ormation of a molecular complex stabilized by the interactions of the negatively charged phosphate group of lecithin with the quinolinium qu aternary nitrogen and the lecithin quaternary nitrogen with the benzen e part of the aminophenyl fragment. The effect of the third aromatic r ing of the benzoquinolinium system on complex stabilization is discuss ed. For the benzoquinolinium derivative with lecithin, the changes in the mass spectrometric fragmentation pattern of the molecule can be us ed as a sensitive and informative method for the characterization of i ntermolecular interactions which may result in molecular complex forma tion. (C) 1997 Elsevier Science B.V.