High-energy CID involves ion kinetic energies in the kilovolt range (typically 1 keV to 20 keV). High-energy CID (HECID) is carried out in magnetic sector mass spectrometers or tandem magnetic sector mass spectrometers and in tandem time-of-flight mass spectrometers (TOF/TOF). Very low collision energies favor ion structure rearrangement, and the probability of direct bond cleavage increases as ion kinetic energy increases, leading to higher ion internal energies. Low-energy CID is highly efficient in fragmenting the selected precursor ions, but the type of fragment ions observed in low-energy CID is strongly dependent on the ion kinetic energy. Low-energy CID is typically carried out with ion kinetic energies less than approximately 1 kiloelectron volt (1 keV). 3 Fourier transform ion cyclotron resonance.By detecting a unique fragment ion, the precursor ion can be detected in the presence of other ions of the same m/z value (mass-to-charge ratio), reducing the background and increasing the limit of detection. Another use is in simply achieving more sensitive and specific detection. In some cases identity can be established based on previous knowledge without determining structure.
Partial or complete structural determination can be achieved. These fragment ions can then be analyzed by tandem mass spectrometry.ĬID and the fragment ions produced by CID are used for several purposes. In the collision some of the kinetic energy is converted into internal energy which results in bond breakage and the fragmentation of the molecular ion into smaller fragments. The selected ions (typically molecular ions or protonated molecules) are usually accelerated by applying an electrical potential to increase the ion kinetic energy and then allowed to collide with neutral molecules (often helium, nitrogen or argon). Collision cell from a Waters Xevo TQ-S triple quadrupole mass spectrometer.Ĭollision-induced dissociation ( CID), also known as collisionally activated dissociation ( CAD), is a mass spectrometry technique to induce fragmentation of selected ions in the gas phase.
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