Case of enantiomer impurity identification by normal-phase chiral high-performance liquid chromatography with optical rotation and mass spectrometricdetection

An impurity produced in the synthesis of compound I is separated and identi fied as its enantiomer II using normal-phase chiral high-performance liquid chromatography (HPLC) with UV absorbance, optical rotation (OR) and mass s pectrometric (MS) detection. The results show that the impurity II and comp ound I have equal and opposite specific rotations, identical MS spectra and the same MS-MS fragmentation pattern, as required for enantiomers. The pro cedures presented demonstrate a novel combination of methods for enantiomer identification and characterization that do not require the preparation of individual enantiomer markers or even the racemic mixture, thus reducing t he need for additional synthetic work. (C) 2000 Elsevier Science B.V. All r ights reserved.