Tandem mass spectrometry studies of β-D-N-glycopyranosides derivatives and the wheat straw lignin

Rahman, Md. Sadiqur (2014) Tandem mass spectrometry studies of β-D-N-glycopyranosides derivatives and the wheat straw lignin. Masters thesis, Memorial University of Newfoundland.

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Abstract

Mass spectrometry is the tool of choice for the analysis of complex biomolecules and therefore it has been used for identification and characterization of different biological molecules such as oligosaccharides and glycoconjugates. In this thesis the first aim of this study was to use three different techniques to analyze the synthetic biological bivalent N-glycosides. The gas phase fragmentation of this series of synthetic bivalent Nglycosides (1-6) have been studied by electrospray ionization (ESI), matrix assisted laser desorption ionization (MALDI) mass spectrometry and quadrupole ion-trap mass spectrometry, in conjunction with using different “in-time” and “in-space” tandem mass spectrometers. In the second aim of this study, MALDI-TOF/TOF-MS and MALDI-TOF/TOFMS/ MS analyses were used which have proven to be a powerful analytical tool capable for ionizing both small and large lignin oligomers. The MALDI mass spectra of the CIMV (CIMV is a world first for the manufacture of whitened paper pulp, sulfur free linear lignin and xylose syrup from annual fiber crops and hardwood).-extracted wheat straw lignin were recorded in the positive ion mode with a high-resolution MALDITOF/ TOF-MS/MS. The positive ion mode MALDI-MS indicated the exact presence of a multitude of oligomers, from which 30 specific oligomeric ions were identified. The structural characterization of this novel series of 30 specific related oligomers was achieved by calculating the exact molecular masses measured by high-resolution MALDI-TOF-MS. High-energy collision-induced dissociation tandem mass spectrometric analyses MALDI-CID-TOF/TOF-MS/MS provided unique dissociation patterns of the complete series of novel precursor ions. These MS/MS analyses provided diagnostic product ions, which enabled us to determination of the exact molecular structures and arrangement of the selected 30 different related ionic species.

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