Categories of exhibits
FAB ion source
Exhibit no. 879
Fast atom bombardment (FAB) uses high-energy neutral atoms (e.g., xenon) to desorb and ionize analytes. Samples dissolved in a liquid nonvolatile carrier (FAB matrix; e.g., glycerol or 3-nitrobenzyl alcohol) are exposed to a beam of energetic atoms in a vacuum. FAB is a soft ionization technique that produces mainly protonated or deprotonated molecules from analytes up to 5 to 6 kDa. This technique was widely used in the 1990s but now is largely replaced by electrospray ionization.
The exhibit is a FAB ion source assembly from a sector mass spectrometer ZAB EQ manufactured by VG Analytical, Ltd. in 1986. It consists of a round mounting plate with a supporting shaft. Copper clad steel springs around the circumference of the plate mated with feedthroughs in source housing cover plate. The shaft supports the ion chamber, where fast atoms coming from a FAB gun hit the target. The ion chamber was not heated. The ion block also contains an aperture for accepting a moving belt HPLC interface. A FAB probe with a target on its tip was inserted to the ion source using a probe assembly mounted on the source housing.
