Rapid Detection Of Glycan Isomers By Ion Mobility-Mass Spectrometry

Carbohydrate is one of the most abundant organic compounds in nature.With the development of modern detection technology and biology,the biological functions of carbohydrate have been constantly revealed,including the control and regulation of cell signaling pathways,intrinsic and extrinsic recognition,and disease pathogenesis.The study of glycosomics is one of the hot spots in the field of life science,which is helpful to further understand the essence of life.Understanding their biological functions remains extremely difficult due to the extremely broad compositions and structure variations of glycans.Although the combination of ion mobility spectrometry and mass spectrometry(IM-MS)has become a promising technique in glycan structure characterization and composition identification,the insufficient resolving power of most IM-MS instruments has limited its utility in performing the comprehensive structure characterization of glycans.To mitigate the low IMS resolving power,metal ion incorporation has been employed to enhance the separation of isomeric glycans and proved to be great potential.However,there is still a lack of systematic studies on the incorporation of metal ions and glycans,including the change of gas phase conformation and the influence of isomeric separation.In general,there is no universal strategy to use sample preparation or gas-phase chemistry to improve glycan isomer separation.In addition,with the need for high-throughput analysis and the increasement of sample complexity,it is especially necessary to improve the accuracy and efficiency of data processing.In order to solve above problems,we have made progress in the following four aspects:Firstly,our research mainly focused on the improvement of spectrum matching algorithm.We came up the pre-search spectrum matching algorithm based on m/z matching.When comparing with TSLP and Ten Peaks,our proposed method has higher accuracy,fewer remaining spectra and shorter computational time.The efficiency of compound identification was greatly sped up by our method.Secondly,we systematically investigated the conformational change of the incorporation of different metal ions(five IA group and four IIA group metal ions)with different glycans(four trisaccharides,four tetrasaccharides,four pentasaccharides and three hexasaccharides)in gas phase.In the generalization of all 280 glycans ions observed in our research,the well-known IM-MS measurement trendlines were still preserved for all the glycan-metal ion complexes which were glycan and charge state dependent only.Thirdly,the database of 280 glycan ion CCS values was built using the IMS-QTOF measurement.These data could be used for the measurement comparation between different IMS instruments and further research on theorical computation.Lastly,the glycan structure change provided by the incorporation of different metal ions can be potentially used to enhance the IMS separation of isomeric glycans.By selecting optimum glycan-metal ion complexes,partial IMS separation was realized for all isomeric glycan pairs used in the experimental study.Baseline IMS separation was achieved for 76 of these isomeric glycan pairs.