SEPARATION OF NICOTINE AND NORNICOTINE ENANTIOMERS VIA NORMAL-PHASE HPLC ON DERIVATIZED CELLULOSE CHIRAL STATIONARY PHASES

This paper describes the enantiorecognition of (+/-)nicotine and (+/-) nornicotine by high-performance liquid chromatography using two deriva tized cellulose chiral stationary phases (CSPs) operated in the normal phase mode. It was found that different substituents linked to the ce llulose backbone significantly influence the chiral selectivity of the derivatized CSP. The results showed that, in general, the tris(4-dmet hylbenzoyl) cellulose CSP (Chiralcel OJ) surpasses tris (3,5-dimethylp henyl carbamoyl) cellulose CSP (Chiralcel OD). On the former column, t he resolution (+/-)nicotine and (+/-)nornicotine enantiomers depended largely on mobile phase compositions. For the separation of the nicoti ne enantiomers, the addition of trifluoroacetic acid to a 95:5 hexane/ alcohol mobile phase greatly improved the enantioresolution, probably due to enhanced hydrogen bonding interactions between the protonated a nalytes and the CSP. For (+/-)nornicotine separation, a reduction in t he concentration of alcohol in the mobile phase was more effective tha n the addition of trifluoracetic acid. Possible solute-mobile phase-st ationary phase interactions are discussed to explain how different add itives in the mobile phase and different substituents on the cellulose glucose units of the CSPs affect the separation of both pairs of enan tiomers. (C) 1998 Wiley-liss, Inc.(dagger)