Enantiomeric separation of some amino acids and derivatives by capillary electrophoresis with 18-crown-6-tetracarboxylic acid as chiral selector

A number of amino acids and derivatives, bought or synthesized, were analyzed by capillary electrophoresis (CE:) with optical active 18-crown-6-tetracarboxylic acid (18C6H(4)) as chiral selector. Besides the primary interaction: i.e., inclusion of the protonated primary amino function in the crown ether cavity, a second interaction mechanism between the substituents on the racemates and the carboxylic acid functions on the crown ether to enhance or suppress enantioselectivity. In certain cases, very high resolutions (R-s > 5) were noted, e.g., R-s 30 for serine benzyl ester. (C) 1999 John Wiley & Sons, Inc.