Strategies for Liquid Chromatographic Resolution of Enantiomers

Abstract

Classic liquid-liquid chromatographic separation relies basically on the distribution of a compound between two immiscible phases by which one is moving (the mobile phase) with respect to the stationary phase. However, in the same way, similar processes occur in the chromatography by classifying the stationary phase as adsorbent which might be a chemically modified surface (e.g. with chiral compounds). The chemical and physico-chemical nature of the phases may vary to a great extent and leads to the various modes of chromatography together with their technical translation. The heart of every chromatographic system is the column which contains the (modified) particles whose surface serves as stationary phase and where the separation of a mixture of compounds (in the following for instance a mixture of stereoisomers or enantiomers) depending on the mobile phase chosen takes place. During the passage of the compounds through the packed column (over the stationary phase) the formation of chromatographic bonds with a concentration profile according to a Gaussian distribution curve takes place, and when the individual sorption isotherms of each component are non-identical, the compounds will become separated. This is the idealistic case, further details on chromatography may be found in more specific textbooks.