Study On Liquid Chromatography-Atmospheric Pressure Ionization Mass Spectrometry In The Structural Determination Of Monosaccharide And Oligosaccharide

Atmospheric pressure ionization(API), including atmospheric pressure chemical ionization(APCI) and electrospray ionization(ESI), is a new ionization mode and ion source. It has been gradually developed since 1980. As the most soft ionizaion technology, its ionization process generates at atmospheric pressure and its ionization efficiency is very high. Atmospheric pressure ionization technology is now routinely applied as liquid chromatography-mass spectrometry interface .In this thesis, the development, current situation and application of liquid chromatography-mass spectrometry are reviewed. The basic principle and characteristic of atmospheric pressure ionization technology are introduced. The emphasis of the research is the structural determination of monosaccharide and oligosaccharide by liquid chromatography-atmospheric pressure ionization mass spectrometry. The following aspects are investigated in the thesis:1. The effect of chemical property of solution on electrospray ionization is studied. The effect of the following aspects on the ionization are discussed by experiments: concentration of organic solvent in the mobile-phase; the formation of sodium adducts in solution; concentration of buffers and the pH of solution. The general rules of how the property of solution affects the electrospray ionization are summarized. The results are beneficial to theselect of experiment conditions and instrument parameters of LC-ESI-MS.2. The MS2 spectras of 10 disaccharides with different linkage are studied by ESI-MS without derivation in advance. The disaccharides with different linkage and configuration fragment in different way. The linkage position and configuration of glucosidic bond can be determined by the mass loss and relative aboundance difference of the characteristic fragment ions. With the fragmentation discipline which has been induced, the linkage type and configuration of glucosidic bond of 7 linear oligosaccharides are determined successfully. This method needn't derivation and has high sensitivity. No literature reported general and thorough researches on the subject with the method at present.3. The oligosaccharides in corn syrup and fructooligosaccharide are analyzed by high-performance liquid chromatography-electrospray ion trap mass spectrometry. The molecular weight and degree of polymerization of the oligosaccharides are determined. In addition, the linkage position of the oligosaccharides are elucidated. The method is very valid and convenient on the analysis of oligosaccharides.4. 11 monosaccharides and 5 methylhexosides are analyzed and distinguished by APCI-MS. With addition of ammonium acetate in the mobile phase, the sugars form adduct ions with NH4+ when ionization. The relative aboundance of fragment ions of adduct ions are quite different from each other. On the basis the sugar epimers are distinguished without derivation. Compared to other reported methods this newly developed method is more straightforward on the distinguish of sugar epimers.