Effect of Temperature on Retention of Cyclic ( -Amino Acid Enantiomers on a Chiral Crown Ether Stationary Phase

Abstract

The isocratic retention of cyclic β-amino acids is studied on a chiral crown ether column (Crownpak CR [+]) at different temperatures. The natural logarithm of the retention factor (In k) depends linearly on the inverse of temperature (1/7). van't Hoff plots afford thermodynamic parameters, such as the apparent change of enthalpy (AH0) and the apparent change of entropy (AS0) for the transfer of analyte from the mobile phase to the stationary phase. The information obtained from the thermodynamic study is discussed, and the qualitative relationships between the structure and the thermodynamic data are evaluated.