Field desorption

Field desorption (FD) is a method of ion formation used in mass spectrometry (MS) in which a high-potential electric field is applied to an emitter with a sharp surface, such as a razor blade, or more commonly, a filament from which tiny "whiskers" have formed.^[1][2] This results in a high electric field which can result in ionization of gaseous molecules of the analyte. Mass spectra produced by FD have little or no fragmentation because FD is a soft ionization method. They are dominated by molecular radical cations M^+. and less often, protonated molecules ${\displaystyle {\ce {[{M}+H]+}}}$. The technique was first reported by Beckey in 1969.^[3] It is also the first ionization method to ionize nonvolatile and thermally labile compounds. One major difference of FD with other ionization methods is that it does not need a primary beam to bombard a sample.^[4]