Preparation And Applications Of Capillary Electrochromatographic Column With β-cyclodextrin Derivatives Microspheres As Chiral Stationary Phase

In this paper, β-cyclodextrin microspheres were prepared by inverse emulsion polymerization and modified by pyromellitic dianhydride(PMDA-β-cyclodextrin microspheres), and their structures and morphology were characterized by infrared spectroscopy, X-ray photoelectron spectroscopy, laser particle size analyzer and scanning electron microscopy. The results showed that β-cyclodextrin microspheres and PMDA-β-cyclodextrin microspheres obtained have uniform particle size(5-10 μm) and smooth surface. Particles immobilized monolithic columns were prepared with the two kinds of microspheres as solid phase using the sol-gel method. At the same time, influencing factors of preparing column were investigated. The results showed that the columns were prepared under the optimal conditions, that is, the collosol was prepared with 0.25 g polyethylene glycol, 2.5 mL aceticacid and 1.5 mL tetramethoxysilane, the mass ratio of the collosol and the microspheres was 2:1, the reaction was carried out in 40℃ water bath for 10 h. The performance of the two columns was assessed and compared with thiourea and DL-glutamic acid under the same electrochromatographic conditions. The average column efficiency of β-cyclodextrin microspheres was up to 17,608 plates/m, the relative standard deviation of retention time was 2.6 %, and the resolution of DL-Glutamic acid was 4.74. The average column efficiency of PMDA-β-cyclodextrin microspheres was up to 55,177 plates/m, the relative standard deviation of retention time was 2.2 %, and the resolution of DL-Glutamic acid was 7.16, which showed that the latter had higher column efficiency and better separation capacity than the former. Finally, the monolithic column of PMDA-β-cyclodextrin microspheres was used to separate the enantiomers of etilefrine hydrochloride, mexiletine hydrochloride, isoprenaline hydrochloride and clorprenaline hydrochloride. Effects of buffer pH, separation voltage and temperature on chiral separation were investigated. Baseline separation of the four kinds of chiral drugs was all achieved.