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Influence of steric hindrance on enantioseparation of Dns‐amino acids and pesticides on terguride based chiral selectors in capillary electrophoresis
Author(s) -
Honzátko Aleš,
Cvak Jan,
Vaingátová Silvie,
Flieger Miroslav
Publication year - 2005
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200400087
Subject(s) - chemistry , steric effects , capillary electrophoresis , enantiomer , chromatography , mandelic acid , selectivity , organic chemistry , catalysis
Three urea derivatives of ergoline‐based chiral selectors (CSs), differing in the size of the urea side chain, i. e. dimethyl‐ (CSI), diethyl‐ (CSII), and diisopropylurea (CSIII), were used to study the effect of steric hindrance on the enantioseparation of dansyl amino acids (Dns‐AAs), pesticides, and mandelic acid under condition of capillary electrophoresis (CE) in linear polyacrylamide coated capillaries. A mixture of organic modifiers (MeOH/THF, 4 : 1 v/v ) in a BGE consisting of 100 mM β‐alanine‐acetate was used to increase the solubility of CSs up to 25 mM. The capillary was filled with CS (high UV absorption), and the inlet and outlet vials contained buffer solutions only. The best enantioseparation of Dns‐AAs was achieved on CSI. Increased steric hindrance of the chiral binding site led to reduction of both enantioselectivity and resolution. The opposite pattern was observed for the separation of mandelic acid enantiomers, where the best enantioseparation and resolution was obtained with CSIII. Most of the pesticides studied reached maximum selectivity on the diethylurea ergoline derivative (CSII). Enantioseparation of fenoxaprop was found to be independent of steric hindrance.