Fast Atom Bombardment

Fast atom bombardment (FAB) ionization techniques is that in mass spectrometers (MS) is used. A solution of the analyte in a liquid hard - volatile matrix with a particle stream of usually inert gases such as argon or xenon (3-8 keV) is bombarded. Conventional matrices are glycerol or 3- nitrobenzyl chloride. This technique is closely related to the secondary ion mass spectrometry. Thus one speaks of Liquid Secondary Ion Mass Spectrometry ( LSIMS ), if instead of noble gas atoms fast ions ( Cs , up to 35 keV ) can be used.

FAB is compared to electron impact a "soft " ionization, and produced mainly protonated molecules, such as [ M H] or deprotonated molecules such as [M -H] -. Represents the type of Ionisierungsprodukte FAB near to process such as the chemical ionization ( CI), electrospray ionization (ESI ), chemical ionization at atmospheric pressure (APCI ) (atmospheric pressure chemical ionization ) and Matrix Assisted Laser-Desorption/Ionisation ( MALDI) (English matrix Assisted laser Desorption / Ionization ).

FAB was used from about 1980 in routine analysis. Due to the lower sensitivity, poorer ion yields and the high degree of contamination in the ion source of this ionization has been displaced since the beginning of 1990 by ESI, APCI, and MALDI. The coupling of high performance liquid chromatography with FAB-MS is much more complex and less efficient than with ESI or APCI -MS.