desorption ionization (DI)

Desorption ionization (DI) is a general term used to group various methods (secondary ion mass spectrometry, fast atom bombardment, californium fission fragment desorption, and plasma desorption) in which ions are generated directly from a sample by rapid energy input into the condensed phase sample. There  may be no discrete  process of desorption (in the thermal sense), but instead a transfer of usually nonvolatile sample molecules into the gas phase as ions that can subsequently be mass-analyzed.