title: An insight into the use of dimethylphenyl carbamate cyclofructan 7 chiral stationary phase in supercritical fluid chromatography: the basic comparison with HPLC.
abstract: Cyclofructan-based chiral stationary phases were previously shown as a promising possibility for separation of chiral compounds in high performance liquid chromatography. In this work retention and enantiodiscrimination properties of the 3,5-dimethylphenyl carbamate cyclofructan 7 chiral stationary phase are described in supercritical fluid chromatography. The results obtained in both of the separation methods were compared. A set of compounds with axial or central chirality was used as analytes. The effect of mobile phase composition, that is, addition of different alcohol modifiers and/or trifluoroacetic acid to carbon dioxide, was examined in the supercritical system. Similarly, mobile phases composed of hexane modified with propan-2-ol and/or trifluoracetic acid were used in liquid chromatography. A linear free energy relationship model was utilized for characterization of interactions that are decisive for retention and separation in both techniques. Dispersion interactions showed similar negative values using both methods. The main contribution of hydrogen bond acidity was also comparable for both methods. The propensity to interact with n- and/or π-electron pairs of solutes was significant only in the supercritical system.
authors.affiliation: Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University in Prague, Prague, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Vozka
authors.forename: Květa
authors.initials: K
authors.lastname: Kalíková
authors.forename: Christian
authors.initials: C
authors.lastname: Roussel
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Armstrong
authors.forename: Eva
authors.initials: E
authors.lastname: Tesařová