Enantiomeric purities have been measured with precisions that are equi
valent to those obtained from chiral chromatography by a simple ligand
substitution reaction into the first coordination sphere of Cu(ll)-ta
rtrate complexes. The model systems are binary mixtures of the ephedri
nes. Ligand exchange reactions are done in bulk aqueous media. The det
ector is polarimetry. Multivariate regression analyses of optical rota
tion data measured at five wavelengths are used to prepare calibration
and prediction models for binary mixtures of the enantiomers.