Effect of mobile phase amine additives on enantio selectivity for phenylalanine analogs

The use of basic mobile phase additives enhances the chiral separation of u nderivatized phenylalanine analogs on a common amylosic column. These addit ives appear to exert their effect through differential disruption of hydrog en binding involved in the recognition process. Several examples of amine i ncreasing retention of the second eluting enantiomer while decreasing reten tion of the other enantiomer were observed. This gave dramatically increase d selectivity and was most commonly observed with cyclopropylamine and cycl obutylamine. The effect was attributed to steric factors involved in the el ution process. (C) DuPont Pharmaceutical Company, Published by Elsevier Sci ence B.V. All rights reserved.