Determination of enantiomers in ephedrine mixtures by polarimetry.

Enantiomeric purities have been measured with precisions that are equivalent to those obtained from chiral chromatography by a simple ligand substitution reaction into the first coordination sphere of Cu(II)-tartrate complexes. The model systems are binary mixtures of the ephedrines. Ligand exchange reactions are done in bulk aqueous media. The detector is polarimetry. Multivariate regression analyses of optical rotation data measured at five wavelengths are used to prepare calibration and prediction models for binary mixtures of the enantiomers.