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Collision-activated dissociation CAD

Collision-activated dissociation (CAD) The same process as collision-induced dissociation (CID). [Pg.372]

The dissociation of gas-phase ions can be a guide to the structure of the ions. There are two ways to dissociate gas-phase ions, either by collision-induced dissociation (CID) sometimes termed collision-activation dissociation (CAD) or by photodissociation. In each method, a mass selected ion is dissociated and the fragment ion (often called a daughter ion) is measured the neutral fragment cannot be experimentally observed. [Pg.358]

Synonymous terms used Collisional activation (CA) and collision-activated dissociation (CAD). [Pg.51]

A special type of mass spectrometric system is an MS/MS (e.g. [45]). In an MS/MS system the ions are generated by any of the available procedures (common El or Cl ionizations are used). The process continues with the ion separation using one of the systems previously described. A particular ion A (named parent ion) is then selected and further dissociated by collision with the molecules of a gas N (collision induced dissociation-CID or collision activated dissociation-CAD) in a reaction zone of the MS/MS system. The common reaction taking place in the CID zone can be described as follows ... [Pg.138]

A method that uses high performance liquid chromatography/ mass spectrometry (HPLC/MS) for the analysis of chlorinated phenoxyacid herbicides is described. During method development different techniques were used to increase both the sensitivity and the specificity of thermospray HPLC/MS for chlorinated acid herbicides. These included the operation of the instrument in the negative chemical ionization (NCI) mode initiated by discharge and the use of a wire-repeller in the ion source for efficient extraction of positive ions. Single quadrupole repeller-induced and multiple quadrupole collision activated dissociation (CAD) experiments were also performed to increase the structural information of the mass spectra. [Pg.62]

The collision activated dissociation (CAD) experiments in the tandem mass spectrometry (MS/MS) mode were conducted at a collision energy of 20 eV with argon at a pressure of approximately 1 mTorr. [Pg.63]

Collision activated dissociation (CAD) studies used argon as a collision gas at a pressure of approximately 1.4 mtorr. Collision energies were adjusted between -9V and -40V with a goal of reducing the precursor ion intensity to less than 20% of the base peak in the product spectrum. [Pg.255]

In the gas phase, both the a- and P-anomers of methyl 3-0-benzyl-2,6-dideoxy-D-arabino-hexopyranoside undergo ready deprotonation of the 4-hydroxyl, and collision activated dissociation (CAD) of these anions leads to E2 elimination, decarbonylation and ring opening fragmentations. Study of the trideuteromethyl a-glycoside, 2,2-dideutero- and dideuterobenzyl a-glycosides support the mechanism proposed. ... [Pg.330]

MS spectra with fragmentation of molecules require collision-activated dissociation (CAD) and triple quadrupole analyzers. In these instruments, the analysis is performed as follows the first quadrupole selects the interesting ion (parent ion), the second produces the fragments from the isolated ion, and the third quadrupole analyzes the fragmentation products (daughter ion spectmm). These steps (ion isolation, fragmentation, and analysis) can be repeated by addition of n quadrupole devices (multisector mass spectrometer) to allow multiple MS/MS experiments (MS") to be performed. [Pg.62]

Fig. 3) allows unambiguous identification of the methylated cycle [35]. For example, the 28-mass-unit shift of B, " B in the collision-activated dissociation (CAD) spectrum C of Figure 3 clearly indicates that this is the MS/MS spectrum of 3, 4 -dimethylcatechin. [Pg.148]

Figure 3 Collision-activated dissociation (CAD) spectra obtained for (A) catechin, (B) 5,7-dimethylcatechin, (C) 3, 4 -dimethylcatechin, (D) 3 -methylcate-chin, (E) 4 -methylcatechin. Voltage cone, 30 V, collision energy, 10 eV argon pressure, 2.8.10 mB. (From Ref. 35.)... [Pg.150]

More energetic ionization methods (in-source decay, ISD) or collisions with inert (collision-activated dissociation, CAD, also known as collision-induced... [Pg.179]


See other pages where Collision-activated dissociation CAD is mentioned: [Pg.1032]    [Pg.460]    [Pg.153]    [Pg.215]    [Pg.1032]    [Pg.126]    [Pg.370]    [Pg.73]    [Pg.181]    [Pg.137]    [Pg.32]    [Pg.230]    [Pg.34]    [Pg.1032]    [Pg.68]    [Pg.405]    [Pg.615]    [Pg.231]    [Pg.133]    [Pg.275]    [Pg.358]    [Pg.133]    [Pg.281]    [Pg.289]    [Pg.404]   
See also in sourсe #XX -- [ Pg.138 ]




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Activated dissociation

Activating collision

CAD

Collision activation

Collisions, activated

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