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Characterization of microcystins using in‐source collision‐induced dissociation
Author(s) -
Kubwabo Cariton,
Vais Natalia,
Benoit Frank M.
Publication year - 2005
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1828
Subject(s) - chemistry , microcystis aeruginosa , cyanobacteria , mass spectrometry , fragmentation (computing) , dissociation (chemistry) , microcystin , chromatography , bacteria , organic chemistry , biology , ecology , genetics
The efficiency of the in‐source collision‐induced dissociation (in‐source CID) technique for the structural characterization of microcystins (MCYSTs) was evaluated. Microcystins that did not contain arginine underwent facile fragmentation to produce characteristic product ions at relatively low cone voltage and could be fully characterized based on their mass spectra. On the other hand, cyclic peptides possessing arginine residues, such as MCYST‐RR, ‐LR, ‐YR and nodularin, were considerably more stable under in‐source CID conditions and required higher cone voltage to induce fragmentation. This behaviour is explained in terms of the mobile proton model for peptide fragmentation that can be used as an indication for the presence of arginine when unknown microcystins are analyzed. In‐source CID was applied to the characterization of microcystins released into water from a Microcystis aeruginosa culture (UTCC299) (UTCC: University of Toronto Culture Collection of Algae and Cyanobacteria). Six microcystins were detected in extracts from UTCC299: I, [D‐Asp 3 ]MCYST‐LR; II, MCYST‐LR; III, isomer of MCYST‐LR; IV, isomer of methyl MCYST‐LR; V, [D‐Asp 3 , Glu(OCH 3 ) 6 ]MCYST‐LR; and VI, [D‐Glu(OCH 3 ) 6 ]MCYST‐LR. In‐source CID provided mass spectral patterns similar to those obtained by CID in the collision cell of the mass spectrometer but was more sensitive for the analysis of microcystins. Copyright © 2005 John Wiley & Sons, Ltd.