The Preparation And Application Of A New Capillary Electrophoresis Chiral Selector

Cyclodextrin is optically active natural polymer, and it is easy to get. Becauseof its unique nature, ionic liquid has a wide range of applications on the separationand purification. As capillary electrophoresis (CE) chiral selector, it has highselectivity and a wide range of applications. The purpose of this study is to prepare anew CE chiral selector by combining the ionic liquid with chiral active moleculesβ-cyclodextrin (β-CD), then to research the application performance on chiralseparation in CE.The modified process for preparing carboxymenthyl-β-cyclodextrin (CM-β-CD).In order to improve the substitution degree and yield, the experiment adopted twosteps to prepare CM-β-CD. Firstly, alkaline in the ice water bath. Secondly, addchloroacetic acid in water bath. By single-factor method and orthogonal experimentexamining, the optimum technological conditions are found as follows:n(NaOH):n(chloroacetic acid)=4.0, total reaction time6h, n(chloroaceticacid):n(β-CD)=6.0, reaction temperature60℃, Under these conditions, the yield andsubstitution degree of CM-β-CD is up to49.4%and6.743.Preparation of the new CE chiral selector [Bmim](β-CD-OCH2COO). First,CM-β-CD and lithium hydroxide generated CM-β-CD lithium salt. Then the new CEchiral selector [Bmim](β-CD-OCH2COO) was prepared by the cation exchangereaction of CM-β-CD lithium salt with1-butyl-3-methyl-imidazolium chloride(BmimCl) ionic liquid. By single-factor method examining effect of reactioncondition on the yield, the optimum technological conditions are found as follows:c(CM-β-CD)=0.10mol/L, n(CM-β-CD):n(BmimCl)=6.4, reaction temperature60℃, total reaction time5h. Under the optimum conditions, the yield of the product isup to45.4%, and the substitution degree is4.0. The products of each step of thereaction are characterized by infrared spectroscopy and NMR to determine thestructure.The study on property and application of [Bmim](β-CD-OCH2COO). Under the capillary zone electrophoresis mode, chiral separation of8chiral compounds.Results showed that the alkaline chiral compounds can achieve effective separation,and better stability, but acidic and neutral chiral compounds have poor separationperformance. Compared with the chiral selector of CM-β-CD, the results showedthat the new CE chiral selector [Bmim](β-CD-OCH2COO) can improve the peakshape and separation selectivityIllustrating the practical application of chiral selector[Bmim](β-CD-OCH2COO). Taking chiral separation of bupivacaine hydrochlorideas a example, examining effect of single-factor on separation performance. Theoptimum separation conditions were found as follows:40mmol/L H3PO4-Tris, thebuffer pH=3.0, the concentration of chiral selector is0.3%, operating voltage is15KV. Under these conditions, the separation degree is6.39.