Fragmentation, in mass spectrometry

In the mass analyzers described, usually the molecular ion ([M+nH] ) is measured. Although this allows specific detection, there are numerous cases where fragmentation is needed either to provide more information or to allow lower detection limits. Fragmentation in LC-MS is usually carried out via collision-induced dissociation (CID). The general principle is as follows  

In step 1, the ion of interest is selected. In step 2, this ion is caused to coDide with gas molecules present, and when the impact is high enough, the molecular ion will fragment These fragments are then detected in step 3. 

There are several ways to perform fragmentation depending on the geometry of the mass spectrometer. Examples of such systems are triple quadrupole MS, ion trap, ion trap-ToF, ToF-ToF, ion trap-Orbitrap, and quadrupole-Orbitrap. It is considered to be bqrond the scope of this book to describe fragmentation in more detail. 

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Metastable ions yield valuable information on fragmentation in mass spectrometry, providing insight into molecular structure. In electron ionization, metastable ions appear naturally along with the much more abundant normal ions. Abundances of metastable ions can be enhanced by collisionally induced decomposition. 

Keywords retro-Diels-Alder fragmentation occurring in gas-phase, fragmentation in mass spectrometry... 

Pyrolysis Process Compared to Ion Fragmentation in Mass Spectrometry. 

Many fragmentations in mass spectrometry proceed so as to form a stable carbo-cation, and the principles that we have developed regarding carbocation stability apply. 

Fragmentation in mass spectrometry, 529-530 Fragment condensation in peptide synthesis, 1080... 

The second key requirement for an imaging techniques is a contrast mechanism, which is some property of the system that varies spatially in the same way as the sample properties to be mapped, e.g. a specific fragment in mass spectrometry, a specific vibrational group frequency, surface reflectivity, etc. In many cases, especially for polymers, samples do not have much inherent contrast under a visible light microscope. Additional contrast is desired. 

Fragmentation in Mass Spectrometry FT-Raman Spectroscopy, Applications... 

See also Chemical Ionization in Mass Spectrometry Fast Atom Bombardment Ionization in Mass Spectrometry Fragmentation in Mass Spectrometry Ion Structures in Mass Spectrometry Ion Trap Mass Spectrometers Ionization Theory Ion Energetics in Mass Spectrometry Ion Collision Theory Metastable Ions Quadrupoles, Use of in Mass Spectrometry Sector Mass Spectrometers Statistical Theory of Mass Spectra Time of Flight Mass Spectrometers. 

See also Environmental Applications of Eiectronic Spectroscopy Fragmentation in Mass Spectrometry ion Dissociation Kinetics, Mass Spectrometry ion Energetics in Mass Spectrometry Laser Appiications in Eiectronic Spectroscopy Metastabie ions Muitipho-ton Spectroscopy, Appiications Negative ion Mass Spectrometry, Methods Photoeiectron-Photoion Coincidence Methods in Mass Spectrometry (PEPiCO) Photoionization and Photodissociation Methods in Mass Spectrometry Spectroscopy of ions Time of Flight Mass Spectrometers. 

See also Fragmentation in Mass Spectrometry ion Dissociation Kinetics, Mass Spectrometry Metastabie ions Photoeiectron-Photoion Coincidence Methods in Mass Spectrometry (PEPICO). 

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