Non-reducing terminal linkage position determination in intact and permethylated synthetic oligosaccharides having a penultimate amino sugar: Fast atom bombardment ionization, collisional-induced dissociation and tandem mass spectrometry

✍ Scribed by Roger A. Laine; Eunsun Yoon; Thomas J. Mahier; Saeed Abbas; Brock de Lappe; Rakesh Jain; Khushi Matta

• Publisher: John Wiley and Sons
• Year: 1991
• Tongue: English
• Weight: 665 KB
• Volume: 20
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/bms.1200200902

✦ Synopsis

Certain linkage positions in oligosaccharides can be discerned by collision-activated disociation mass spectrometry, rationalized by molecular modelling. Previous work on synthetic oligosaccharides has suggested that daughter ion patterns can distinguish among intact compounds which terminate in a-L-fucose and have a penultimate amino sugar. The current study indicates that tbese observations can be extended to oligosaccharides terminating in @D-gPlaCtOW. In addition, we have ohserved that protonated, ammoniated and lithiated molecular ions all produce linkage-speciiic daughter ion spectra in these two sets of oligosaccharides. Sodiated molecular ions could be fragmented usefully under high collision energy offset conditions; potassiated ions were stable and not dissociable under conditions available in a triplequadrupole instrument. We also show linkage discernment among the permethylated set of these six synthetic oligosaccharides. Methylated derivatives of this set of compounds give more useful product ions, including a Slinkage specific ion. A novel relationship was noted by a plot of collision energy against (daughter ionlparent ion) ratio, which gave a unique slope for each of the non-reducing terminal linkage positions 3,4 and 6 in the set of six compounds. The slope of this plot is related to the ability of each linkage position in the oligosaccharide to absorb collisional energy. Rotational freedom of the individual glycosidic linkage is hypothesiied to play a role in this phenomenon.