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Separations of enantiomers by preparative capillary isotachophoresis
Author(s) -
Kaniansky Dušan,
Šimuničova Eva,
Ölvecká Eva,
Ferancová Adriana
Publication year - 1999
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/(sici)1522-2683(19990901)20:13<2786::aid-elps2786>3.0.co;2-v
Subject(s) - isotachophoresis , chromatography , capillary action , chemistry , enantiomer , capillary electrophoresis , materials science , electrolyte , organic chemistry , electrode , composite material
The use of capillary isotachophoresis (ITP), operating in a discontinuous fractionation mode, for preparative separations of enantiomers of chiral compounds was studied. The ITP separations were carried out in the column‒coupling configuration of the separation unit provided with the preseparation column of a 1.0 mm ID and the trapping column of a 0.8 mm ID. Such a configuration of the CE separation unit offers several working regimes suitable to preparative separations of enantiomers. 2,4‒Dinitrophenyl‒ DL ‒norleucine (DNP‒Norleu) was employed as a model analyte in our experiments with β‒cyclodextrin serving in the electrolyte solutions as a chiral selector. The preparative separations lasting about 20 min were evaluated by ITP and (more often) by capillary zone electrophoresis (CZE). It was found that one preparative run provided up to 14 μg of pure DNP‒Norleu enantiomers. This corresponded to a 75 times higher production rate of ITP relative to a maximum value of this parameter as estimated for preparative CZE runs in cylindrical capillaries (0.5 pmol/s). About 75% of the DNP‒Norleu enantiomers loaded into the preparative equipment could be recovered in pure enantiomer fractions. Contiguous natures of the zones in the ITP stack and adsorption losses of the enantiomers in the isolation step were found to set practical limits for a further enhancement of the recovery rates in the isolation of pure enantiomers.