20] Fast atom bombardment mass spectrometry

Abstract

One of the most important pieces of experimental data in the analysis of the molecular structure of biological compounds is the determination of the mass of the molecule. While a number of methods are used to determine the molecular mass of peptides, oligosaccharides and oligonucleotides [e.g., gel-permeation chromatography, and native and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE)], the most accurate method is mass spectrometry (MS). An enormous impact has been made on the biochemical research community, by the introduction of desorption ionization techniques, for mass spectrometric analysis. Fast atom bombardment (FAB) mass spectrometry has found a particular niche in the mass analysis of biological molecules up to approximately 5000 Da. Fast atom bombardment mass spectrometry (FABMS) was developed by Barber and co-workers in an attempt to alleviate the surface charging, associated with static secondary ion mass spectrometry. However, the technique made a major impact when the same group published the novel procedure of introducing the analyte in a viscous liquid matrix. Since that time, FAB has been used to analyze a wide variety of molecules, ranging from oligopeptides to organometallics, and buckminsterfullerenes. Owing to its ability to introduce polar or charged molecules into the gas phase, with concomitant ionization, FABMS has been used extensively in the analysis of compounds of biological origin. This chapter discusses the principles of FABMS and continuous-flow (CF) FABMS, the methods for obtaining optimal spectral results, and some applications to biochemical research.