Abstract
In reversed-phase mode, chromatographic retention is investigated thermodynamically for an enantiomeric pair on an amylose-derivative bonded phase. Ehthalpies and entropies of solute transfer (mobile to stationary phase) are calculated from retention data by evaluation of van't Hoff plots.
Conformational change of the stationary phase is observed at about 20°C. The enantioselectivity is exclusively driven by enthalpy above about 20°C, whereas below about 20°C enantioseparation was achieved by the combination of enthalpy and entropy. The inclusion process of the enantiomer, retained stronger on the stationary phase, plays a important role for chiral recognition on the amylose-derived stationary phase.