title: Negative-ion electrospray mass spectrometry of neutral underivatized oligosaccharides.
abstract: Negative-ion electrospray mass spectrometry (ES-MS) with collision-induced dissociation (CID) and MS/MS scanning on a quadrupole-orthoganal time-of-flight instrument provide a sensitive means for structural analysis of neutral underivatized oligosaccharides. Molecular mass information can be readily obtained from the dominant [M - H]- ions in the ES mass spectrum formed with subnanomole amounts of oligosaccharides, and similar sensitivity is available from CID-MS/MS to give structural details. The CID spectra of 14 oligosaccharides demonstrated that sequence and partial linkage information can be derived and isomeric structures can be differentiated. Series of C-type fragment ions give sequence information while the double glycosidic D-type cleavage of a 3-linked GlcNAc or Glc and the saccharide ring fragmentation of the 0,2A-type from 4-linked GlcNAc or Glc can provide partial linkage information. The distinctive D- and A-cleavages are important for differentiation of oligosaccharide type 1 and type 2 chains and to define the blood group H, Le(a), Le(x), Le(b), and Le(y) determinants carried by their fucosylated analogues.
authors.affiliation: MRC Glycosciences Laboratory, Imperial College School of Medicine, Northwick Park Hospital, Harrow, Middlesex, UK. w.chai@ic.ac.uk
authors.forename: W
authors.initials: W
authors.lastname: Chai
authors.forename: V
authors.initials: V
authors.lastname: Piskarev
authors.forename: A M
authors.initials: AM
authors.lastname: Lawson
mesh_terms: D002240:Carbohydrate Sequence; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D009844:Oligosaccharides