Abstract
Two diastereomeric complex ions of a chiral material (enantiopure) with an equivalent mixture of a deuterium labeled one enantiomer and an unlabeled another enantiomer are observed in a mass spectrum, and the chiral discrimination ability or enantiopurity of the chiral materials are evaluated quantitatively on the basis of the relative peak intensity of the complex ions. In this paper the methodology, the design of the chiral material for the method, and detection of chirality using mass spectrometry are described. The relative peak intensity of the complex ions of chiral crown ether derivatives with chiral ammonium ions in the fast atom bombardment mass spectrometry was in good agreement with the ratio of the association constants in solution. While, that in the electrospray ionization (ESI) mass spectrometry is depressed since the evaporation of the chiral materials containing the deuterium-labeled/unlabeled enantiomeric pair in the ESI process changes the relative concentration of the complex ions. However, the relative peak intensity in ESI mass spectrometry shows high reproducibility under the same measurement conditions. The deuterium-labeled/unlabeled enantiomer pair of a metal complex were used to evaluate the optical purity of a chiral carboxylic acid in ESI mass spectrometry.
