Effect of additives on chiral selectivities by beta-cyclodextrin in capillary electrophoresis based on the phenomenon of solvatochromism

To explore the relationship between solvatochromic parameters and chiral se lectivity, we measured the effect of organic solvents as buffer additives o n the chiral selectivities of dansyl-phenylalanine, dansyl-leucine, and pro pranolol by b-cyclodextrin in capillary electrophoresis. Negative relations hips between the additive's log L-16 and chiral selectivities were observed for the systems added C-1-C-6 alcohols, C-1-C-5 amines, and C-1-C-5 acids. The chiral selectivities also decreased significantly with the additive's increasing hydrogen bond basicity. The decreased selectivities of additives on dansyl-phenylalanine is much greater than on dansyl-leucine. The chiral selectivities of propranolol remained unchanged with all the additives in the buffer. Although most additives studied decreased chiral selectivities, the data presented in this work provided some initial information on chira l selectivities relating to solvatochromic parameters. (C) 1998 DuPont Phar maceuticals Company. Published by Elsevier Science B.V. All rights reserved .