Collision-induced dissociation

Low-energy CID is typically carried out with ion kinetic energies less than approximately 1 kiloelectron volt (1 keV).

The pressure in Q2 is higher and the ions collides with neutral gas in the collision cell and are fragmented by CID.

This produces a mass spectrum of the CID fragments from which structural information or identity can be gained.

Ions trapped in the ICR cell can be excited by applying pulsed electric fields at their resonant frequency to increase their kinetic energy.

Trapped fragment ions or their ion-molecule reaction products can be re-excited for multistage mass spectrometry (MSn).

[7] Higher-energy collisional dissociation (HCD) is a CID technique specific to the orbitrap mass spectrometer in which fragmentation takes place external to the trap.

HCD does not suffer from the low mass cutoff of resonant-excitation (CID) and therefore is useful for isobaric tag–based quantification as reporter ions can be observed.