Study On The Drug Separation Based On Chiral OT Columns Coated With Silica Nanozeolites In CEC-AD System

1.PrefaceCapillary electrochromatography?CEC?is one of promising electrophoresis separation modes,which combines the high separation efficiency of electrophoresis and the high selectivity of high-performance liquid chromatography.Especially in recent years,CEC attracts wide attention due to its increasingly wide use in the separation and analysis of chiral drugs.This chapter mainly introduces the principle and instrument of CEC,the application of nano materials in open tubular CEC?OT-CEC?and the new progresses of chiral selectors in CEC.In this thesis,the novel chiral OT columns were prepared by immobilizing the chiral selector and silica nanozeolite?zeolite SiO₂NPs?on the inner wall of the capillary,and the prepared chiral OT columns were applied for the separation of chiral drugs based on the CEC–AD system.2.Study on the preparation of?-CD/zeolite SiO2NPs/PDA-OT chiral column and its application for the analyses of active components in CatechuIn this work,taking advantage of the strong adhesion of polydopamine?PDA?,the?-CD/zeolite SiO₂NPs/PDA-OT chiral columns were prepared by immobilizing?-cyclodextrin??-CD?with host guest function and zeolite SiO₂NPs with large specific surface areas and stable chemical property on the inner wall of the bare capillary.Catechin and epicatechin were selected as the model molecules,and the main effects of the concentration of zeolite SiO₂NPs,?-CD,dopamine,and oxidant on the separation performance of the OT columns were investigated in detail using OT-CEC-AD system.Under the optimized electrophoretic conditions,this developed method was applied for the analysis of Chinese herbal medicine Catechu from different sources.The limits of detection of catechin and epicatechin in the sample matrix were 14.3-16.2 ng·mL^-1?S/N=3?and the average recovery data were in the range of 83.8-117.7%.The relative standard deviations of the migration time and peak area of the analytes were less than 5.0%for run-to-run and day-to-day reproducibility.This OT-CEC-AD method using?-CD/zeolite SiO₂NPs/PDA-OT chiral column had good stability and accuracy,which provided a potential new method for the separation of chiral drugs and the identification of the Chinese herbal medicines.3.Study on the preparation of BSA@zeolite SiO2NPs/PDA-OT chiral columns and their separation of chiral drugsBased on the previous research,the novel BSA@zeolite SiO₂NPs/PDA-OT chiral columns were prepared by layer-by-layer coating method to immobilize PDA,zeolite SiO₂NPs,and bovine serum albumin?BSA?with chiral recognition ability on the inner wall of the capillary.In the experiments,ephedrine?E?and pseudoephedrine?PE?were used as the chiral model molecules,and the OT-CEC-AD system was used to systematically explore the preparation parameters of the chiral OT columns,including the concentrations of the coating materials and buffer composition.Furthermore,the prepared chiral OT columns were characterized by scanning electron microscope and electroosmotic flow.Under the optimized experimental conditions,three groups of chiral drug model molecules?E/PE,salbutamol and ritodrine?were baseline separated,respectively;this developed method was successfully applied for the analysis of Chinese herbal medicine Ephedrae Herba.The proposed method employed a simple running buffer without any buffer additives,and gave high detection sensitivity,providing an alternative in the separation of chiral drug.