Enantioselective Separations with Supercritical Fluids - Review

This paper presents a review of the literature covering separations of enantiomers achieved with supercritical fluids. Supercritical fluid chromatography (SFC) is the main technique represented but chiral extraction (chiral SFE) and simulated moving bed (SMB) are also present. First of all, a historical view of the technique is presented. Then stationary phases, mobile phases and operating conditions are discussed, with a particular focus on the effect of operating parameters on the resolution. Detection issues are presented. The interest of SFC for screening methods and for the preparative scale is demonstrated. Comparison with other chromatographic techniques, namely gaseous-phase chromatography (GC) and high-performance liquid chromatography (HPLC) is provided. While the pharmaceutical industry is the principal application area of enantioselective separations, other examples with agrochemicals or fragrances are also presented. Foreword: This article focuses on main developments in the field of chiral separations with supercritical fluid chromatography and related techniques, as well as representative applications. It is not intended to be a comprehensive review of all papers published on the topic of chiral separations with supercritical fluids. However, it is believed that the publications mentioned here are representative of the evolution of the technique over more than 25 years of use. Several excellent reviews covering other aspects of chiral separations and/or supercritical fluid chromatography are also mentioned where appropriate.