Highly Accurate Quantitative Analysis Of Enantiomeric Mixtures from Spatially Frequency Encoded 1H NMR Spectra

Anal Chem. 2018 Feb 6;90(3):1595-1600. doi: 10.1021/acs.analchem.7b02411. Epub 2018 Jan 19.

Abstract

We propose an original concept to measure accurately enantiomeric excesses on proton NMR spectra, which combines high-resolution techniques based on a spatial encoding of the sample, with the use of optically active weakly orienting solvents. We show that it is possible to simulate accurately dipolar edited spectra of enantiomers dissolved in a chiral liquid crystalline phase, and to use these simulations to calibrate integrations that can be measured on experimental data, in order to perform a quantitative chiral analysis. This approach is demonstrated on a chemical intermediate for which optical purity is an essential criterion. We find that there is a very good correlation between the experimental and calculated integration ratios extracted from G-SERF spectra, which paves the way to a general method of determination of enantiomeric excesses based on the observation of 1H nuclei.

Publication types

  • Research Support, Non-U.S. Gov't