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Sulfate migration in oligosaccharides induced by negative ion mode ion trap collision‐induced dissociation
Author(s) -
Kenny Diarmuid T.,
Issa Samah M. A.,
Karlsson Niclas G.
Publication year - 2011
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.5157
Subject(s) - chemistry , sulfation , fragmentation (computing) , oligosaccharide , dissociation (chemistry) , mass spectrometry , collision induced dissociation , sulfate , ion , quadrupole ion trap , protonation , sialic acid , ion trap , analytical chemistry (journal) , chromatography , tandem mass spectrometry , organic chemistry , biochemistry , computer science , operating system
Migration of sulfate groups between hydroxyl groups was identified after collision‐induced dissociation (CID) of sulfated oligosaccharides in an ion trap mass spectrometer in negative ion mode. Analysis of various sulfated oligosaccharides showed that this was a common phenomenon and was particularly prominent in sulfated oligosaccharides also containing sialic acid. It was also shown that the level of migration was increased when the sulfate was positioned on the flexible areas of the oligosaccharides not involved in the pyranose ring, such as the extra‐cyclic C‐6 carbon of hexoses or N ‐acetylhexosamines, or on reduced oligosaccharide. This suggested that migration is dependent on the spatial availability of the sulfate in the ion trap during collision. It is proposed that the migration is initiated when the negatively charged ‐SO 3 – residue attached to the oligosaccharide precursor becomes protonated by a CID‐induced proton transfer. This is supported by the CID fragmentation of precursor ions depleted of acidic protons such as doubly charged [M – 2H] 2– ions or the sodiated [M + Na – 2H] – ions of oligosaccharides containing one sulfate and one sialic acid in the same molecule. Compared to the CID fragmentation of their monocharged [M – H] – ions, no migration was observed in CID of proton depleted precursors. Alternative fragmentation parameters to suppress migration of sulfated oligosaccharides also showed that it was not present when sulfated oligosaccharides were fragmented by HCD (High‐Energy C‐trap Dissociation) in an Orbitrap mass spectrometer. Copyright © 2011 John Wiley & Sons, Ltd.