Determining the change of enantiomeric excess is very important to confirm the reaction termination in the chiral synthesis or enantiomer resolution. The change of conversion and enantionmeric excess in the synthesis or resolution can be determined by HPLC with online polarimeter. Using this method,the optimum results are obtained in the synthesis of D-(-)-phenylglycine butyl ester hydrochloride which is used for resolving mandlic acid and the porcine pancertic lipase-catalyzed transesterification.
