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Mass spectrometry for the characterization of unsulfated chondroitin oligosaccharides from 2‐mers to 16‐mers. Comparison with hyaluronic acid oligomers
Author(s) -
Volpi Nicola,
Zhang Zhenqing,
Linhardt Robert J.
Publication year - 2008
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.3760
Subject(s) - chemistry , glycosidic bond , tetrasaccharide , chondroitin , mass spectrometry , disaccharide , fragmentation (computing) , tandem mass spectrometry , electrospray ionization , electrospray , chromatography , ion , chondroitin sulfate , stereochemistry , analytical chemistry (journal) , organic chemistry , polysaccharide , glycosaminoglycan , biochemistry , operating system , computer science , enzyme
This study reports for the first time the complete liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) and tandem mass spectrometry (MS/MS) analyses performed in negative ion mode of saturated unsulfated chondroitin oligosaccharides up to 16‐mers and comparison with hyaluronic acid (HA) oligomers differing only in the nature of the hexosamine residue. MS/MS of the chondroitin disaccharide on the singly charged precursor at m/z 396.1 afforded a glycosidic cleavage C 1 product ion at m/z 192.9. In the tetrasaccharide, C 2 ( m/z 396.0) and C 3 ( m/z 572.0) product anions were generated by glycosidic cleavage. A C 5 [M–2H] 2− product ion at m/z 475.1 was generated by the glycosidic cleavage of the hexasaccharide, and a C 7 ion ( m/z 664.6, charge state of −2) was produced from the octasaccharide. The same fragmentation pattern of deprotonated oligomers was observed for the largest oligosaccharides, from 10‐ to 16‐mers. There has been no previous report of MS/MS spectra for unsulfated chondroitin oligomers of these sizes. Unsulfated saturated chondroitin oligosaccharides with x‐mer units and larger than a tetrasaccharide dissociate to almost exclusively form C X–1 ‐type ions. Saturated HA oligomers also afforded the same fragmentation pattern as deprotonated oligomers by ESI‐MS and MS/MS analyses. Thus, under the experimental conditions used in the current study, we were unable to distinguish between unsulfated chondroitin and HA. Copyright © 2008 John Wiley & Sons, Ltd.