Fragmentation (chemistry)

Fragmentation is a type of chemical dissociation. Fragmentation of a molecule can take place by a process of heterolysis or homolysis.

It is a phenomenon observed in mass spectrometry where it is used as a tool to find the structural formula of a molecule, process called structural elucidation.

It can occur in the ion source (in-source fragmentation) where it is generally not a desired effect. Ion source conformation is an important criterium in the level of fragmentation observed.

Desired fragmentation is made in the collision zone (post-source fragmentation) of a tandem mass spectrometer. It is a part of gas phase ion chemistry and there are different types of mass fragmentation:

• collision-induced dissociation (CID),
• electron-capture dissociation (ECD),
• electron-transfer dissociation (ETD)
• electron-detachment dissociation (EDD),
• photodissociation, particularly infrared multiphoton dissociation (IRMPD) and blackbody infrared radiative dissociation (BIRD),
• surface-induced dissociation (SID),
• charge remote fragmentation,
• Higher-energy C-trap dissociation (HCD).

The certain structures favour fragmentation the α-cleavage and the McLafferty rearrangement are two examples for the often observed fragmentations.

See also

• Mass chromatogram
• Mass spectrum analysis
• Tandem mass spectrometry

External links

• Fragmentation patterns in the mass spectra of organic compounds