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Preparation And Chromatographic Evaluation Of-Zwitter Ion Polymer Stationary Phase For High Performance Liquid Chromatography

Posted on:2021-01-10Degree:MasterType:Thesis
Country:ChinaCandidate:X H LouFull Text:PDF
GTID:2381330605952050Subject:Chemistry
Abstract/Summary:PDF Full Text Request
As the complexity of analyzing samples increases,the single-mode stationary phase type has become difficult to adapt to the separation requirements currently faced.The advantages of hydrophilic interaction chromatography?HILIC?and mixed mode chromatography?MMC?in separating strongly polar and complex samples have received more and more attention.Research and preparation of highly selective stationary phases and further elaboration of their mechanism of action It is an important content in the field of chromatography.In this paper,a series of hydrophilic interaction chromatographic stationary phases and mixed-mode chromatographic stationary phases were developed using the superior performance of zwitterions,and their separation capabilities,partitioning mechanisms and practical applications were investigated accordingly.The main contents are as follows:1.Through bonding polyethylene maleic anhydride to the surface of amino silica gel by nucleophilic substitution reaction and hydrolyzing the residual maleic anhydride,a weak cationic exchange/hydrophilic interaction mixed-mode stationary phase?Sil-PolyCOOH?for high performance liquid chromatography was prepared by bonding polyethylene maleic anhydride to the surface of amino silica gel via a nucleophilic substitution reaction,followed by hydrolysis of the residual maleic anhydride.The new stationary phase material was characterized by solid-state 13C nuclear magnetic resonance analysis and?-potential measuremeents.The chromatographic performance and retention mechanism of this stationary phase were evaluated using nucleosides and nucleic bases as probes.The effects of mobile phase composition,ion strength,and pH on the retention factor were investigated.The results show that the retention mechanism of the stationary phase involves both hydrophilic distribution interaction and multiple forces between the host and guests.The stationary phase also showed good separation performance for saccharides,diquat,and paraquat.2.Based on the work in the previous chapter,a new polymer-based zwitterionic HILIC stationary phase?ZIC-Sil-Poly?was prepared by aminolysis of residual maleic anhydride with tris?2-aminoethyl?amine.The stationary phase was characterized by infrared spectroscopy,?-potential and elemental analysis.In the HILIC mode,the immobilization shows good separation selectivity for polar compounds such as riboglycans,bases,sugars,etc.The adsorption displacement model shows that the retention of the immobilized relative polar compounds does not only depend on the analyte in the water-rich layer And the distribution between the mobile phase is also affected by the effects of hydrogen bonding and electrostatic interaction between the analyte and the stationary phase.The buffer salt concentration and pH in the mobile phase both have a certain effect on the retention of solutes.Finally,the stationary phase showed good separation in the rapid detection of papaverine and thebaine in urine.1.Developed a new RPLC/HILIC mixed mode stationary phase?Sil-PolyZIC-ODS?.Using octadecene and allyl glycine as ligands,a radical polymerization reaction was initiated on the surface of the modified silica gel matrix,so that the two groups formed alternate copolymerization on the silica gel surface,and a reverse phase/hydrophilic mixed mode stationary phase was prepared.Elemental analysis,infrared spectroscopy,X-ray photoelectric energy spectroscopy and other methods were used to characterize the stationary phase.In reversed phase mode,the separation performance of the stationary phase was investigated using mono-substituted benzene,polycyclic aromatic hydrocarbons,and di-substituted benzene isomers as solute factors.In the reversed phase mode,the stationary phase can effectively separate nucleoside base polar compounds,and compared with the C18 column,it shows good separation ability.Under different ratios of acetonitrile-water mobile phase systems,polar compounds show the retention characteristics of reverse phase/hydrophilic mixed mode.
Keywords/Search Tags:Hydrophilic interaction chromatography, mixed mode chromatography, weak cation exchange, zwitterionic polymer, reversed-phase mode, chromatographic performance
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