Lai CK, Ng DCM, Pang HF, Le Blanc JCY, Hager JW, Fang DC, Cheung ASC, Chu IK. Laser-induced dissociation of singly protonated peptides at 193 and 266 nm within a hybrid linear ion trap mass spectrometer.
RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013;
27:1119-27. [PMID:
23592116 DOI:
10.1002/rcm.6545]
[Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/08/2013] [Accepted: 02/13/2013] [Indexed: 05/16/2023]
Abstract
RATIONALE
We implemented, for the first time, laser-induced dissociation (LID) within a modified hybrid linear ion trap mass spectrometer, QTrap, while preserving the original scanning capabilities and routine performance of the instrument.
METHODS
Precursor ions of interest were mass-selected in the first quadrupole (Q1), trapped in the radiofrequency-only quadrupole (q2), photodissociated under irradiation with a 193- or 266-nm laser beam in the third quadrupole (q3), and mass-analyzed using the linear ion trap.
RESULTS
LID of singly charged protonated peptides revealed, in addition to conventional amide-bond cleavages, preferential fragmentation at Cα -C/N-Cα bonds of the backbone as well as at the Cα -Cβ /Cβ -Cγ bonds of the side-chains. The LID spectra of [M+H](+) featured product ions that were very similar to the observed radical-induced fragmentations in the CID spectra of analogous odd-electron radical cations generated through dissociative electron-transfer in metal-ligand-peptide complexes or through laser photolysis of iodopeptides.
CONCLUSIONS
LID of [M+H](+) ions results in fragmentation channels that are comparable with those observed upon the CID of M(•+) ions, with a range of fascinating radical-induced fragmentations.
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