8.12 Chromatographic Separations and Analysis: Macrocyclic Glycopeptide Chiral Stationary Phases

Abstract

The macrocyclic glycopeptide chiral selectors are an important class of chiral stationary phases (CSPs) for liquid chromatography. They were introduced at the end of the last century. Three selectors are especially useful as they have a broad enantiorecognition capability: ristocetin A, vancomycin, and teicoplanin. The enantiomers best recognized by these three CSPs include amino acids and peptides, but also a huge number of chiral acids and bases and an impressive list of active pharmaceutical ingredients (APIs). This chapter describes in detail the physicochemical properties of macrocyclic glycopeptides including insights into their three-dimensional structure and interaction possibilities. The unique chromatographic polar ionic mode (PIM) works with waterless polar organic mobile phases (mainly methanol or ethanol) containing small amounts of acid and base so that the ionization state of the chiral selector is adjusted according to the enantiomer to discriminate. This class of CSP is multimodal working with a 100% polar solvent (PIM or polar organic mode) but also in the reversed phase with an aqueous buffer mobile phase and a normal phase with alkane–alcohol mixtures. A very large table lists the separation condition of chiral APIs on macrocyclic glycopeptide CSPs.