The Methodology For Analysis Of Oligosaccharides At High Sensitivity Using Mass Spectrometry

The analysis method and strategy of extrinsic and intrinsic glycans were set up by ESI-MS in the thesis. In the MS analysis process of extrinsic glycans, the alginate oligosaccharides were applied as the object. According to the different cross-ring fragment ions produced by the MS/MS in the mannuronic and guluronic acid residues, the two isomers were differentiated and the sequence of the alginate oligosaccharides were confirmed. In the MS analysis process of intrinsic glycans, the O, N-glycnas in the glycoproteins were applied as the object. The methodology of chemical release, profile and mapping of O, N-glycans were performed by the ESI-MS.One of the aim of this thesis is setting up method for the determination of sequence of extrinsic oligosacharides at high sensitivty by MS. Negative-ion electrospray tandem mass spectrometry (ES-MS/MS) with collision-induced dissociation (CID) is attempted for sequence determination of alginate oligosaccharides, derived from polyanionic alginic acid, polymannuronate, and polyguluronate by partial depolymerization using either alginate lyase or mild acid hydrolysis. Sixteen homo- and hetero-oligomeric fragments were obtained after fractionation by gel-filtration and strong-anion exchange high-performance liquid chromatography. The product-ion spectra of these alginate oligosaccharides were dominated by intense B-, C-, Y- and Z-type ions together with 0,2A- and 2,5A-ions of lower intensities. Internal mannuronate residues (M) produce weak but specific decarboxylated Zint-ions (Zint ? 44 Da; int: denotes internal), which can be used for distinction of M and a guluronate residue (G) at an internal position. A reducing terminal M or G., although neither gives rise to a specific ion, can be identified by differences in the intensity ratio of fragment ions of the reducing terminal residue...