Preparation, Characterization And Application Of Novel β-cyclodextrin Functionalized Organic-based Capillary Monolith For Micro-HPLC

Chirality is one of the fundamental properties in the nature, chiral factors exist in themolecular structure of compounds known as chiral compounds. Although well advanced, thedevelopment of novel chiral stationary phases (CSPs) in HPLC is still a hot research topic. Inrecent years, chiral monolithic columns have attracted considerable interests by virtue of theirfacile preparation methodology and good column characteristics, such as permeability,efficiency etc. In this research, several novel β-cyclodextrin (β-CD) functionalizedorganic-based monolithic columns have been well prepared and studied.In the first chapter, the importance of enantioseparation and the application of β-CD inenantioseparation have been well reviewed. In the meantime, silica-based monolith andorganic-based monolith has been introduced. The development and prospects of the β-CDfunctionalized organic-based monolith have been described in detail.In the second chapter, a novel, facile and efficient one-step preparation strategy of β-CDfunctionalized methacrylate based monolith was presented for the first time. Themono-(1H-1,2,3-triazol-4-ylmethyl-2-methylacryl-β-CD)(PMA-β-CD) was prepared via clickreaction between PMA and mono-6-azido-β-CD under microwave conditions. Then in situcopolymerization of a homogeneous mixture made of PMA-β-CD, a suitable crosslinker,porogenic solvents, and an initiator were carried out within a capillary to afford apoly(PMA-β-CD-co-EDMA) monolith. The composition of the polymerization mixture wasoptimized in order to obtain satisfactory performance. The optimized monolithic columnswere applied to the separation of polar compounds due to its hydrophilic exterior environmentof multiple hydroxyl groups. Their application to chiral separations was also investigated.In the third chapter, a novel derivatized β-CD (PMA-sulfated-β-CD) functionalizedmethacrylate based monolith was prepared using above “one-step” strategy. The structures ofthe monomers were characterized by FT-IR and mass spectrometry (MS). Thephysicochemical properties and column performance of the fabricated monolithic columnswere evaluated by scanning electron microscopy and micro-HPLC. The impact of grafting on the separation of some nucleosides, small peptides and traditional Chinese medicines (TCMs)was studied.In the fourth chapter, a novel and facile one-pot copolymerization approach wasdeveloped for the preparation of a β-CD modified organic polymer monolith for the first time.The synthesis of the novel monomer GMA-EDA-β-CD and the subsequent copolymerizationwere realized in the same vial without any purification step of the chiral monomer, andtherefore the whole fabrication process could be finished facilely in a few hours. The stability,permeability, β-CD density and reproducibility of the monolithic column were systematicallyevaluated using elemental analysis, SEM and micro-HPLC. The optimizedpoly(GMA-EDA-β-CD-co-EDMA) monolithic columns were applied to the enantioseparationof acidic chiral compounds. Enantioseparation conditions and mechanism have also beeninvestigated in detail.In the fifth chapter, this study aimed at searching for a new type of derivatized β-CDbased CSPs for effective and multimodal chiral HPLC separations. Another β-CD, which haveseven amino groups, was used to prepare the β-CD based CSPs through the improved one-potstrategy (6-amino-β-CD). The obtained monolith exhibited uniform micorostructure,satisfactory column permeability, high meachanical stability, ultrahigh column efficiency andgood reproducibility. The retention behavior on the monolithic column was investigated bystudying the influence of ACN on the retention time of a test mixture of thiourea and toluene.The optimized poly(GMA-6-amino-β-CD-co-EDMA) monolithic columns were applied to theseparatation of some small peptides, ketones and the enantioseparation of acidic chiralcompounds.In the sixth chapter, The poly(MQD-co-HEMA-co-EDMA) monolithic column wassuccessfully applied for the enantioseparation of20FMOC-amino acids and7phenoxy acidherbicides, and also successfully applied for the quantitative of phenoxy acid in the herbicide.In the seventh chapter, the conclusions and prospects of this thesis was clearly described.