8.15 Chromatographic Separations and Analysis: Diastereomeric Derivatization for Chromatography

Of the three branches of the simultaneous determination of enantiomers based on separation methods (indirect methods based on precolumn covalent, diastereomeric derivatization with homochiral derivatizing agents and separation on achiral stationary phases, and direct separation on chiral stationary phases or on achiral stationary phases using chiral additives in the mobile phase), the first is the subject of this chapter. Advantages and disadvantages of this approach are discussed. It is concluded that the commercial availability of a great variety of homochiral derivatizing agents and several publications up to the present time indicate that this approach cannot be considered outdated even in the era of direct methods. The main methods for the derivatization of amines, amino acids, alcohols, and carboxylic acids are presented and illustrated by several examples published mainly in the last decade. Derivatization with achiral reagents aiming at enhancing the possibilities of direct methods is also discussed.