CHIRAL RECOGNITION AND ENANTIOMERIC RESOLUTION BASED ON HOST GUEST COMPLEXATION WITH CROWN ETHERS IN CAPILLARY ZONE ELECTROPHORESIS

A chiral crown ether is successfully used as a pseudostationary phase in capillary zone electrophoresis to separate optically active amines. On the basis of the results obtained from the separation of more than 20 aminos, two recognition mechanisms are proposed: (I) the four crown other substituents act as chiral barriers for the guest molecules and (II) lateral electrostatic interactions occur between host and guest. These results are confirmed by thermodynamic studies on the host-guest complexes. Best resolutions are achieved if the chiral center is adjacent to the amine functionality. However, even racemates with a chiral center in the delta-position to the amine could be resolved excellently. For the separation of aliphatic amino acids a method has been developed allowing detection by an indirect detection mode.