Dynamically Generated Chiral Stationary Phase Systems with β-Cyclodextrin Derivatives

Abstract

It is demonstrated that chromatographic phase systems with a dynamically generated stationary phase with β-cyclodextrin derivatives are a powerful and versatile tools for enantioseparations. In this technique a small amount of β-cyclodextrin derivatives (di-, tri-methylated and peracetylated) is added to the eluent. These compounds are strongly adsorbed on the ODS surface where they form new adsorption sites with strong stereoselective interactions with enantiomers leading to a change in retention properties and selectivity of the phase system. This technique leads to columns with excellent time stability and good reproducibility of the enantioselectivity. The choice of a suitable β-cyclodextrin derivative offers a wide range possibilities to optimize enantioselectivity. It is shown that the kinetics of the sorption-desorption process of the solute on the chiral stationary phase largely contribute to the efficiency of the columns making an appropriate choice of the flow rate an important parameter for the optimization of the separations.