A novel in-situ strategy for enantiomeric discrimination and selective identification of multicomponent carboxylic acids in foods

Abstract

Chiral carboxylic acids are ubiquitous in nature and are of pivotal importance in practical applications in the field of food science and pharmaceuticals. Simultaneous enantiomeric analysis of carboxylic acids mixtures is a significant research goal. Herein, we demonstrate a new strategy involving the use of the highly selective chiral derivatizing agent (R)-2-amino-1,1,1-trifluoropropane ((R)-TFPA) for the enantiomeric discrimination and selective identification of carboxylic acids in mixtures, even structurally similar drugs. The key success of this sensing approach lies in the distinguishable ¹⁹F NMR signals of diastereoisomers formed via derivatization of the substrates by (R)-TFPA. The utility of this approach was demonstrated by simultaneously differentiating 20 chiral carboxylic acids in a complicated mixture with accurate determination of the enantiomeric excess (ee). Most importantly, our approach can be applied to food analysis, where the diverse carboxylic acids in real samples without separation were unambiguously identified, such as vinegar, yogurt, and grape.

Keywords: (19)F NMR; Carboxylic acids; Enantiomeric discrimination; Food analysis; Simultaneous analysis.