LAUSR

Graphical abstract Figure. No Caption available. HighlightsEnantiomers of carbocyclic &bgr;‐amino acids possessing limonene skeleton were separated.Macrocyclic glycopeptide‐based chiral stationary phases were thermodynamically characterized.Decreased retentions were accompanied with increased separation factors with increasing temperature. Abstract Polar‐ionic and reversed‐phase high‐performance liquid chromatographic separations of limonene‐based cyclic &bgr;‐amino acid enantiomers were carried out by using macrocyclic glycopeptide‐based chiral selectors applying Chirobiotic T, TAG and R columns. The effects of additives, concentration of the co‐ and counter‐ions and the temperature in polar‐ionic mobile phase systems were studied. The influence of pH, MeOH content and alcohol additives were investigated in the reversed‐phase mode. The difference in the change in standard enthalpy &Dgr;(&Dgr;H°), entropy &Dgr;(&Dgr;S°), and free energy &Dgr;(&Dgr;G°) was calculated from the linear van't Hoff plots derived from the ln &agr; vs 1/T curves in the temperature range 5–40 °C. Unusual temperature behavior was observed on Chirobiotic TAG for most of the analytes: decreased retention times were accompanied with increased separation factors with increasing temperature, and separation was entropically‐driven. For two of the studied analytes enthalpically‐driven enantioseparations were observed. The elution sequence was determined in all cases, but no general rule could be established.