Chiral Separations by High‐Performance Liquid Chromatography

Abstract

AbstractThe word ‘chiral’ is derived from the Greek word ‘cheir’, which means hand. Chiral molecules are molecules that are related to each other in the same way that a left hand is related to a right hand. These molecules are mirror images of each other and are nonsuperimposable. Chiral separations traditionally have been considered among the most difficult of all separations since enantiomers have identical chemical and physical properties in an achiral environment. In this article, we will focus on techniques used in high‐performance liquid chromatography (HPLC). Most chiral separations by HPLC are accomplished via direct resolution using a chiral stationary phase (CSP). In this technique, a chiral resolving agent is bound or immobilized to an appropriate support to make a CSP, and the enantiomers are resolved by the formation of temporary diastereomeric complexes between the analyte and the CSP. In the last decade, the focus of research in chiral HPLC has shifted from the search for novel CSPs to the improvement of currently existing CSPs. The most important developments have been the increasingly faster methods and a trend for increased efficiency using smaller support particles and superficially porous particles in CSP columns.