Polar-ionic and hydro-organic mobile phase mode of high-performance liquid chromatographic separations of 23 sterically constrained primary β(3)-amino acid enantiomers containing, alkyl, aryl or heteroaryl side-chains were carried out by using newly developed Cinchona alkaloid-based zwitterionic chiral selectors and the stationary phases Chiralpak ZWIX(+)™ and ZWIX(-)™. In the polar-ionic mode, the effects of the composition of the bulk solvent and the natures of the co- and counter-ions, while in the hydro-organic mode, the effects of the pH, the counter-ion concentration and the structures of the analytes were investigated. The separations of the enantiomers of these 23 primary β(3)-amino acids, which can be classified as a series of quasi- (pseudo-) homologs, were optimized in both chromatographic modes. The elution sequence was determined in most cases and a reversal of elution order on ZWIX(+)™ and ZWIX(-)™ column was observed. On the basis of this intermolecular recognition model between the selectors and the given enantiomers an indirect assignment of the resolved enantiomer via chromatography is proposed.

Department of Analytical Chemistry Faculty of Science Regional Centre of Advanced Technologies and Materials Palacký University 17 listopadu 12 771 46 Olomouc Czech Republic

Department of Analytical Chemistry University of Vienna Währingerstrasse 38 1090 Vienna Austria

Department of Inorganic and Analytical Chemistry University of Szeged Dóm tér 7 6720 Szeged Hungary

Institute of Pharmaceutical Chemistry University of Szeged Eötvös u 6 6720 Szeged Hungary

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