EVIDENCE FOR LINKAGE POSITION DETERMINATION IN COBALT COORDINATED PENTASACCHARIDES USING ION-TRAP MASS-SPECTROMETRY

A methodology to determine the linkage position of oligosaccharides is presented. In order to illustrate this technique, several oligosaccha rides and disaccharides were ionized by electrospray and analyzed in a Paul trap mass spectrometer. Multiple stage tandem mass spectrometry experiments were used to determine linkage and structural information for the following four cobalt coordinated and singly charged ([M+Co-H] (+)) pentasaccharides: Lacto-N-fucopentaose I, II, III, and V. In orde r to differentiate between linkage positions, multiple low energy coll ision induced experiments with mass selected C type ions have been car ried out in an ion trap mass spectrometer. Because of the coordination with cobalt, which directs the dissociation pathways, these C type io ns undergo specific fragmentation reactions upon low energy collision induced dissociation. These dissociation pathways are unambiguously de pendent on their linkage position, thus allowing differentiation betwe en 1-->2, 1-->3, 1-->4, and 1-->6 linkage positions throughout the oli gomers. Studies on various linked disaccharides and N-acetyl-disacchar ides, which are smaller constituents of the pentasaccharides, were use d to verify and confirm the results obtained from the pentasaccharides . (J Am Soc Mass Spectrom 1998, 9, 1125-1134) (C) 1998 American Societ y for Mass Spectrometry.