ENANTIOMER SEPARATION OF UNDERIVATIZED TOCAINIDE AND RELATED-COMPOUNDS BY CGC USING AMMONIA AS CARRIER GAS

Enantiomer separation of underivatized tocainide and related compounds has been investigated on a column coated with XE-60-L-Val-(S)-alpha-P EA using ammonia as the mobile phase. No separation was observed when nitrogen or ammonia was initially used as carrier gases. However, afte r treating the column with a flow of ammonia at 160 degrees C for one week, enantiomeric separations of some tocainide analogues were obtain ed. This effect remained even when nitrogen was subsequently used as t he carrier gas. A possible explanation for the change in the enantiose lectivity of the column may be that the stationary phase undergoes a c onformational change when exposed to ammonia. This possibility was inv estigated by conformational analysis studies using theoretical calcula tions and H-1-NMR spectroscopy. (C) 1996 John Wiley & Sons, Inc.