Practice question

Fast atom bombardment, introduced before electrospray and MALDI, ionizes nonvolatile biomolecules by embedding sample in viscous glycerol matrix placed on a metal target. A beam of high-energy argon or xenon atoms accelerated to kiloelectronvolt energies bombards surface, sputtering analyte molecules with protonation and desorption into gas phase. Resulting ions show minimal fragmentation, enabling measurement of peptides and small proteins. The technique relies on momentum transfer from neutral atoms rather than electron ionization, matrix desorption by laser, or X-ray irradiation, representing an early soft ionization approach for biological mass spectrometry applications historically significant.