Fast Atom Bombardment Mass Spectroscopy (FAB-MS) is a technique used to measure the mass-to-charge ratio of ions in a sample by bombarding it with high-energy atoms. The spelling of this word can be broken down into individual phonemes using the IPA phonetic transcription system. "Fast" is pronounced /fæst/, "Atom" is pronounced /ˈætəm/, "Bombardment" is pronounced /bɒmˈbɑːd.mənt/, "Mass" is pronounced /mæs/, and "Spectroscopy" is pronounced /spekˈtrɒs.kə.pi/. This complex spelling reflects the technical precision required for FAB-MS measurements in the field of chemical analysis.
Fast atom bombardment mass spectrometry (FAB-MS) is a technique used in analytical chemistry and biochemistry to analyze and identify the molecular structure of organic compounds, especially biomolecules such as peptides, proteins, and nucleic acids. It involves the bombardment of the sample with a beam of high-energy atoms, usually xenon or argon, which causes the molecules to desorb and ionize. The resulting ions are then accelerated and focused into a mass spectrometer for separation and detection.
In FAB-MS, the sample is typically dissolved in a liquid matrix that aids in the desorption and ionization process. The matrix absorbs energy from the atom beam and transfers it to the sample, causing the molecules to break up into smaller fragments and ionize. This generates a mixture of molecular ions, fragment ions, and matrix ions in the ion source of the mass spectrometer.
The ions are then accelerated into the mass analyzer, which separates them based on their mass-to-charge ratio. The resulting mass spectrum provides valuable information about the molecular weight and composition of the analyte, as well as structural details such as the presence of specific functional groups or modifications. By comparing the mass spectra of known compounds to that of unknown samples, FAB-MS allows for the identification and characterization of organic molecules in complex mixtures.
Although FAB-MS has been largely replaced by more advanced techniques such as electrospray ionization and matrix-assisted laser desorption/ionization, it remains a valuable tool in certain applications, particularly in the analysis of large biomolecules.