Mass spectrometry collisionally activated dissociation

Selected reaction monitoring is one of several techniques carried out by consecutive mass filters. These techniques are collectively called tandem mass spectrometry or mass spectrometry/mass spectrometry or simply MS/MS. The process In Q2 is collisionally activated dissociation. 

Tandem mass spectrometry has been particularly effective in molecular struclure dctemiinaiiiins. To increase the number and absolute abundance of peaks in the secondary mass spectrum, it is necessary lit add energy to the separated primary ions. Collisionally activated dissociation tCAD) is frequently used. 

The cyclopropylmethyl cation has recently been generated in the gas phase from both homoallyl chloride and cyclopropylmethyl chloride and studied using collisional activated dissociation mass spectrometry.216 Interestingly, cyclobutyl chloride, which yields the cyclopropylmethyl cation in the condensed phase, gives a substantial amount of the bicyclobutonium ion in the gas phase. 

Hsu, F.-F., and Turk, 1 1999. Structural Characterization of triacylglycerols as lithiated adducts by electrospray ionization mass spectrometry using low-energy collisionally activated dissociation on a triple stage quadrupole instrument. J. Am. Soc. Mass Spectrom., 10, 587-599. 

LC Taylor, RL Johnson, L St John-Williams, T Johnson, SY Chang. The use of low-energy collisionally activated dissociation negative-ion tandem mass spectrometry for the characterization of dog and human urinary metabolites of the drug BW 1370U87. Rapid Commun Mass Spectrom 8 265, 1994. 

Sulfatides (3-sulfogalactosylceramides) were initially detected by mass spectrometry using FAB ionization but spectrum showed a number of fragmentations which complicates considerably the method (Ohashi and Nagai, 1991). More recently structural characterization of sulfatides by collisional-activated dissociation (CAD) was described in quadrupole ion-trap tandem mass spectro-metric methods with electrospray ionization. With the method [M - H]- ions of sulfatides yield abundant structurally informative ions that permit unequivocal assignments of the long-chain base and fatty acid constituent including the location of double bond (Hsu and Turk, 2004). The major sulfatide molecular species are quantified similarly in the 2 clinical forms (motor and... 

The regiospecific characterization of TAG as lithiated adducts by collisionally activated dissociation tandem mass spectrometry (CAD-MS ) has been reported by Hsu and Turk [9]. The ions were reported from the loss of fatty acids as a,p-unsaturated fatty acid specific at the sn-2 position of TAG of lithiated adducts. We have used these ions to quantitate six regiospecific diricinoleoylacylglycerols (RRAcs) containing ricinoleate (a hydroxyl fatty acid) in castor oil [10],... 

Several desorphon and spray ionization methods can be used to convert S5mthehc polymers into intact molecular or quasimolecular ions (vide supra), whose exact m/z ratio identifies the composition of the polymer. For structural informahon about the polymer, the dissociation behavior or ion-molecule reactions of the polymer ions must be studied. Such reactions, which rarely take place during the soft ionization processes necessary to generate intact gas phase ions from synthetic macromolecules, are most conveniently assessed by tandem mass spectrometry (MS/MS). With MS/MS, a specific precursor ion is mass-selected, so that its reactivity can be investigated without perturbation from the other ions formed upon ionization. The reaction products of this ion are then mass-analyzed and collected in the MS/MS spectrum. MS/MS studies on polymer ions have so far focused on their spontaneous ("metastable") or collision-induced fragmentation. The fragments arising in these reactions are displayed in metastable ion (MI) or collisionally activated dissociation (CAD) spectra, respectively. Customarily, MI spectra acquired with a TOF mass analyzer have been named "postsource decay (PSD)" spectra similarly, CAD is often referred to as CID (collision-induced dissociation). ... 

Chowdhury, S.M. Munske, G.R. Tang, X. Bruce, J.E. Collisionally activated dissociation and electron capture dissociation of several mass spectrometry-identifiable chemical cross-linkers. Ana/. Chem. 2006, 78, 8183-8193. 

A. Williams, E.R. Furlong, J.J.P. McLafferty, F.W. Efficiency of collisionally-activated dissociation and 193-nm photodissociation of peptide ions in Fourier-transform mass-spectrometry. J. Am. Soc. Mass Spectrom. 1990,1, 288-294. 

Hsu FF, Turk J. Electrospray ionization with low-energy collisionally activated dissociation tandem mass spectrometry of glycerophospholipids mechanisms of fragmentation and structural characterization. J Chromatogr B. 2009 877 2673-95. 

Hsu F-F, Turk J, Stewart ME, Downing DT. Structural studies on ceramides as lithiated adducts by low energy collisional-activated dissociation tandem mass spectrometry with electrospray ionization. J Am Soc Mass Spectrom. 2002 13 680-95. 

Hsu, E.-E. and Turk, J. (2005) Electrospray ionization with low-energy collisionally activated dissociation tandem mass spectrometry of complex lipids Structural characterization and mechaiusm of fragmentation. In Modern Methods for Lipid Analysis by Liquid Chromatography/Mass Spectrometry and Related Techiuques (Byrdwell, W.C., ed.). pp. 61-178, AOCS Press, Champaign, IL. 

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