Chiral Separations of Five Organic Catalysts by Cyclodextrin-modified Capillary Zone Electrophoresis

Chiral separation is very important and become a significant task of analytical chemistry in many fields. Capillary electrophoresis (CE) is a technique undergoing rapid development for chiral separation at the present time. With its high efficiency, simple operation, and extremely small sample volume,CE has become a powerful tool for chiral separation. There are many chiral selectors, such as cyclodextrins (CDs), proteins, chiral surfactants, antibiotics, bile salts, using in CE chiral separation. CDs has been most wildly used in them. Cyclodextrin (CD) is a cyclic sugar made of certain glucose units in which each has 5 chiral centers and it shows the shape of cavity with a big end and a small end. The inside of CD is hydrophobic and the outside is hydrophilic. The chiral selectivity of CD comes from the formation of host-guest compound between CD and analytes. The differences of the hydrogen-bond and the other interactions between CD and two enantiomers cause enantio-selectivity.