US Patent 7911608 Spectroscopic determination of enantiomeric purity

A new method and strategy for the quantitative determination of enantiomeric purity that combines polarimetry, spectroscopy, and chemometric modeling. Spectral data is collected after a light beam is passed through a first polarimeter, a sample of a chiral compound, and a second polarimeter oriented at a 45 degree angle relative to the first polarimeter. The spectral data for samples of known enantiomeric composition is subjected to a type of multivariate regression modeling known as partial least squares (“PLS-1”) regression. The PLS-1 regression produces a mathematical model that can be used to predict the enantiomeric composition of a set of samples of unknown enantiomeric purity.