PHOTOFRAGMENTATION STUDIES OF BIOMOLECULAR IONS OF AMINO-ACIDS USING A TANDEM REFLECTRON TIME-OF-FLIGHT MASS-SPECTROMETER

A tandem reflectron time-of-flight mass spectrometer developed in Glas gow University was used for the investigation of photofragmentation of the molecular ions of the amino acid derivatives: PTH-tryptophan, PTH -valine, and PTH-alanine as well as of cytosine and guanine, The molec ular ions were generated by matrix-assisted laser desorption/ionizatio n and the laser photofragmentation of selected ions took place at the turn-around point of ions in the reflectron. The fragmentation mass sp ectra of the molecular ions of these amino acid derivatives have been observed and possible fragmentation pathways are discussed.