Use of circular dichroism and artificial neural networks for the kineticspectrophotometric resolution of enantiomers

The circular dichroism (CD) technique was used to resolve 1-phenylethylamine enantiomers by their differential rate of reaction under non-pseudo first-order kinetic conditions with the chiral feagent (-)-citronellal. The same reaction was also monitored under pseudo first-order conditions using UV¯VIS spectrophotometry and the results provided by the two techniques were compared by using principal component regression (PCR), partial least-squares regression (PLSR) and artificial neural networks (ANNs) for multivariate calibration. The best results were obtained by compressing the data matrix provided by the CD technique with principal component analysis (PCA) and using the scores of the principal components as input for the ANN. The relative standard error (R.S.E.) of prediction thus obtained was about 3% for both enantiomers.