title: Comparison of the separation performances of cinchona alkaloid-based zwitterionic stationary phases in the enantioseparation of β2- and β3-amino acids.
abstract: The enantiomers of twelve unusual β2- and β3-homoamino acids containing the same side-chains were separated on chiral stationary phases containing a quinine- or quinidine-based zwitterionic ion-exchanger as chiral selector. The effects of the mobile phase composition, the nature and concentration of the acid and base additives and temperature on the separations were investigated. The changes in standard enthalpy, ∆(∆H°), entropy, ∆(∆S°), and free energy, ∆(∆G°), were calculated from the linear van't Hoff plots derived from the ln α vs. 1/T curves in the studied temperature range (10-50 °C). The values of the thermodynamic parameters depended on the nature of the selectors, the structures of the analytes, and the positions of the substituents on the analytes. A comparison of the zwitterionic stationary phases revealed that the quinidine-based ZWIX(-)™ column exhibited much better selectivity for both β2- and β3-amino acids than the quinine-based ZWIX(+)™ column, and the separation performances of both the ZWIX(+)™ and ZWIX(-)™ columns were better for β2-amino acids. The elution sequence was determined in some cases and was observed to be R < S and S < R on the ZWIX(+)™ and ZWIX(-)™ columns, respectively.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary. ilisz@chem.u-szeged.hu.
authors.forename: István
authors.initials: I
authors.lastname: Ilisz
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary. lazar@pharm.u-szeged.hu.
authors.forename: Nóra
authors.initials: N
authors.lastname: Grecsó
authors.affiliation: Department of Chemistry, University of Warsaw, Pasteura str. 1, 02-093 Warsaw, Poland. misicka@chem.uw.edu.pl.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Misicka
authors.affiliation: Department of Chemistry, University of Warsaw, Pasteura str. 1, 02-093 Warsaw, Poland. dulok@chem.uw.edu.pl.
authors.forename: Dagmara
authors.initials: D
authors.lastname: Tymecka
authors.affiliation: Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös utca 6, H-6720 Szeged, Hungary. lazar@pharm.u-szeged.hu.
authors.forename: László
authors.initials: L
authors.lastname: Lázár
authors.affiliation: Department of Analytical Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria. wolfgang.lindner@univie.ac.at.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Lindner
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary. apeter@chem.u-szeged.hu.
authors.forename: Antal
authors.initials: A
authors.lastname: Péter
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002930:Cinchona Alkaloids / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013237:Stereoisomerism; D013816:Thermodynamics
chemical_list: D000596:Amino Acids; D002930:Cinchona Alkaloids