Tunable Ionization and Fragmentation by Nanoparticle-assisted MALDI-TOF MS for Structural Determination of Isomeric Oligosaccharides
Date Issued
2011
Date
2011
Author(s)
Li, I-Che
Abstract
Before advances in tandem MALDI MS had been developed for unambiguous structure determination, MALDI-TOF MS has traditionally been used only for the molecular weight determination of biomolecules. However, analysis of low molecular weight analytes in MALDI-TOF MS is limited due to the severe interference by matrix signals. Recent progresses on the functionalized nanomaterials have impacted the background-free analysis of small molecule. By using matrix functionalized nanoparticles for background-free measurement, we reported a tunable ionization/fragmentation strategy to generate analyte product ions in the MS mode by tuning different concentration of surface modified nanoparticles for rapid structural characterization.
Among these biomolecules, the analysis of carbohydrates is relatively challenging due to their inherent low ionization efficiency. Using the isomeric saccharides as model system, soft and background-free measurement can be achieved with enhanced signals under low nanoparticle concentration. On the other hand, high concentration of nanoparticle imparted high internal energy to the analytes and promoted fragmentation. Compared with other MS/MS strategies, DHB@MNP is likely to induce oligosaccharide corss-ring cleavage and generate unique fragments. Based on the controllable extent of the soft/harsh ionization, this strategy distinguished isomeric sucrose and lactose, LewisA and LewisX trisaccharides, and LewisB and LewisY tetrasaccharides. Also, the investigation of key components of the composition of nanoparticle in the ionization and fragmentation mechanism suggested three important features of DHB@MNP: (1) the energy pooling by the Fe3O4 core may account for ionization and fragmentation of the oligosaccharides at high concentration of the MNP, (2) the coating of SiO2 reduces the background signals and mitigates the internal energy imparted by the core, and (3) the DHB conjugated on the surface enhance the signals of the analyte and its fragments.
Subjects
MALDI-TOF
fragmentation
oligosaccharide
Type
thesis
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