Preparation And Application Of Zwitterionic Polymer Stationary Phases In Hydrophilic Interaction Chromatography

With the development of chromatographic technology,Hydrophilic interaction chromatography（HILIC）has attracted more and more attention because of its unique advantages in the separation of polar compounds.Compared with normal phase and reversed phase chromatography,HILIC can make up for the shortcomings of the two in their applications.For example,reversed-phase chromatography has weak or no retention for polar substances,and normal-phase chromatography has low solubility for polar compounds.Therefore,HILIC undertakes a more and more important role in the separation and analysis of many ionic,strong polarity compounds and proteomics in recent years.As the core of chromatographic technology,the type and character of stationary phase directly affect the separation effect.Therefore,the aim of this research is to develop new stationary phases prepared into monolithic or packed columns for the separation of polar compounds in hydrophilic chromatography.Based on this research,the separation of polar analytes was contrast between the monolithic and packed columns.The first chapter provides a detailed overview of the development,retention mechanism and application of HILIC in drug analysis.In addition,the difference between monolithic column and packed column is briefly introduced.In the second chapter,the monolithic was prepared by the one-step in situ co-polymerisationoffunctionalmonomer N,N-dimethyl-N-（3-methacrylamidopropyl）-N-（3-sulfopropyl）ammoniumbetaine（SPP）,crosslinker 1,4-Diacrylylpiperazine（PDA）,porogens（Me OH and p H=7,50 m M Na H₂PO₄）and initiator azobisisobutyronitrile（AIBN）within 100μm I.D.capillaries.The Polymerization parameters were systematically optimized in order to obtain a satisfactory column with high column efficiency,good separation ability and good mechanical properties.The resulted Poly（SPP-co-PDA）monolith was characterized by SEM,EDS,FT-IR and micro-HPLC.In order to study the chromatographic behavior of Poly（SPP-co-PDA）monolith,we selected nucleoside bases,phenols,and benzoic acid as analytes.The results showed that the hydrophilic monolithic column has good separation ability and selectivity for the above compounds.In conclusion,the new zwitterionic stationary phases have shown excellent chromatographic behavior for a variety of polar solutes under HILIC mode,and have a great potential as a new type of stationary phases for HILIC.In the third chapter,in order to investigate the difference of separation ability of the same type of monomers between the packed column and the monolithic column,a novel zwitterionic HILIC stationary phase,named Si O₂@SH-SPP,was synthesized on the basis of“thiol-ene”click chemistry and reversible addition fragmentation chain transfer polymerization（RAFT）.The characterization of elemental analysis,EDS,N₂-adsorption,TGA and solid-state ¹³C nuclear magnetic resonance,etc demonstrated the successful preparation of zwitterionic stationary phase.Then a new capillary-packed column was prepared by packing technology.Finally,the conventional liquid chromatography was split and modified,and the separation of polar compounds was investigated under the same separation conditions as the Poly（SPP-co-PDA）monolithic column and the difference between the two was explored.The results showed that the separation conditions of monolithic columns are not suitable for packed columns of the same type of monomer.In the fourth chapter,the second type of zwitterionic stationary phase,N,N-dimethyl-N-methacryloxyethyl-N-3-（sulfopropyl）ammonium betaine（SPE）was also prepared with“thiol-ene”click chemistry and RAFT.The resulting material was characterized by TGA,EDS,¹³C nuclear magnetic resonance and so on.In addition,phenolic compounds were used as analytical objects to characterize the chromatographic behavior of the new synthesized HILIC stationary phase.In the fifth chapter,the conclusions of this research were described.And the future work is also prospected.