CID

Collision-induced dissociation is a technique designed to fragment molecular ions in the gas phase. The molecular ions are usually allowed to collide with neutral gas molecules (helium, nitrogen or argon). In the collision, kinetic energy is converted into internal energy which results in bond cleavage resulting in the fragmentation of the molecular ion. These fragment ions can then be analyzed by a mass spectrometer. Partial or complete structural determination can be achieved through interpretation of these fragment spectra. CID also finds use for achieving increased sensitivity by looking for unique fragment or fragments of a specific ion. The presence of these ions confirms the presence of a particular molecule, this is particularly useful where a complex matrix or in the presence of an isobaric ion is encountered. This process essentially reduces the background and increases the limit of detection.