Characterization of Biomolecules by Fast Atom Bombardment Mass Spectrometry

Abstract

During the past several years there have been a number of advances in the field of particle-induced desorption which have increased the number of techniques and the type of compounds amenable to mass spectrometric analysis. Currently, plasma desorption (PD), secondary ion mass spectrometry (SIMS), fast atom bombardment (FAB) and laser desorption (LD) are employed for the analysis of large, thermally labile compounds such as peptides and glycoconjugates. These soft ionization techniques primarily produce abundant ions associated with the molecular weight of the sample. and depending on compound structure they may also provide structural information. The type and extent of fragmentation observed in the FAB mass spectra of peptides is dependent on the number of components, pH, matrix, type of ions detected (pos. or neg.) and amino acid sequence. Furthermore, when several components are present in a single FAB sample, often the only strictly reliable information obtained is the molecular weights of the components. In order to characterize the type and extent of fragmentation of peptides and glycoconjugates in FABMS, several closely related sets of compounds of varying compositions have been recorded,in the normal positive ion and negative ion modes and in the positive ion MSMS mode. In the MSMS mode both single and multiple component samples are examined using a JEOL JMS HX110/HX110 four sector mass spectrometer of EBEB geometry with high-mass range and good resolution in MS2.