Vibrational circular dichroism study and gas chromatographic analysis of chiral epichlorohydrin.

In recent years, there have been numerous incidents of serious accidents related to impurities of optical isomers, particularly in pharmaceutical treatment, environmental problems, and pesticide application. Among these impurities, chiral epichlorohydrin (ECH) is an important C3 synthon and a potentially genotoxic impurity. The enantiopure forms of S-ECH and R-ECH are key raw materials for synthesizing many drugs, which make it important to accurately quantify the specific conformation of chiral epichlorohydrin in pharmaceuticals. In this paper, we achieved the separation of chiral ECH by gas chromatography (GC) and based on the combination of vibrational circular dichroism (VCD) experiments and theoretical calculations, the qualitative method of chiral ECH was achieved without relying on a single enantiomeric standard. [Display omitted] • By comparing the theoretical VCD spectra of the single ECH enantiomer with the experimental VCD spectra of the R/S-ECH mixture, the configuration of the dominant enantiomer in the nonracemic mixture was determined. • Combined theoretical and experimental VCD spectra with GC, the peak of R/S-ECH in GC was successfully identified. A GC method for the determination of chiral ECH independent of a single enantiomer standard is first proposed. • The concentration of the single ECH enantiomer in the mixture can be accurately quantified. [ABSTRACT FROM AUTHOR]