Tandem mass spectrometric analysis Subject

Tandem mass spectrometry summarizes the numerous techniques where mass-selected ions (MSI) are subjected to a second mass spectrometric analysis (MS2). [111,112] Dissociations in transit through the mass analyzer may either occur spontaneously metastable. Chaps. 2.7.1, 2.8.2) or can result from intentionally supplied additional activation, i.e., typically from collisions with neutrals. Below, we will chiefly discuss the collision process as such and its consequences for the further fate of the ions. Instrumental aspects of tandem MS are included in Chap. 4 and applications are presented in Chaps. 7-12. 

The ethylene bromonium and 1-bromoethyl cations and their neutral and anionic counterparts have been the subject of a tandem mass spectrometric study of dissociation and gas-phase redox reactions. IR and Raman studies of the bioactive bromonium cation (19), as its hydrogensulfate salt, agree with the results of an X-ray structure determination, and theoretical calculations are also in agreement, except for the details of the NO2 groups. The azaallenium ion (22) is an intermediate in the photolysis of (20) (21) and (22) could both be seen. Flash photolysis of (23) leads to (24), (25), and (26), all of which could be trapped by nucleophiles (27) was not an intermediate. NMR lineshape analysis of the spectmm of (28) leads to reaction rate constants of formation for both the intimate ion pair (29) and the solvent-separated ion pair (30). ... 

It has been demonstrated also that the iTRAQ tandem mass spectrometric quantitative analysis strategy can be used in conjunction with the quadrupole ion trap by performing multiple stages of mass analysis (that is, MS ) [125], For example, chemical derivatization with the iTRAQ reagent not only labels the N-terminus of a peptide, but the lysine side chain also. Thus, tryptic peptides with a modified lysine residue present at the C-terminus will produce a yj product ion at m/z 291 following ClD-tandem mass spectrometry. To generate the low m/z iTRAQ reporter ions required for quantitation, the yj product ion is isolated and subjected to data-dependent CID-MS. Using this approach, peptide identification is achieved in the MS/MS scan, while quantitation is achieved via MS. ... 

Capriotti AL, Foglia P, Gubbiotti R, et al. Development and validation of a liquid chromatography/ atmospheric pressure chemical photoionization-tandem mass spectrometric method for the analysis of mycotoxins subjected to commission regulation (EC) No. 1881/2006 in cereals. J Chromat A. 2010 1217 6044-51. 

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