Effect of mobile phase composition on the separation of propranolol enantiomers using a perphenylcarbamate beta-cyclodextrin bonded chiral stationaryphase

An analytical column packed with a novel perphenylcarbamate beta -cyclodext rin bonded chiral stationary phase was used to separate propranolol enantio mers. Good separation results were obtained using triethylammonium acetate (TEAA) buffer and methanol mixtures as the mobile phase. Effects of the met hanol concentration, buffer concentration and pH value on the retention and the enantioselectivity of propranolol enantiomers were investigated on thi s column. The retention times and the separation factor decrease with incre ase of the methanol concentration as expected in reversed-phase HPLC. At tr ace TEAA amount, the solute eluted out with anti-Langmuirian band profiles, their retention times decreased quickly with increase of TEAA concentratio n and attained a minimum at a TEAA concentration of 20 ppm. Above 20 ppm, s olute band profiles changed to a Langmuirian shape, the retention times of enantiomers increased with increasing buffer concentration, and eventually, they attained asymptotes at ca. 1% TEAA. A simulation considering the diff erent interactions between the solute and the additive at above and below 2 0 ppm TEAA concentration as well as system peaks interference can successfu lly explain the anti-Langmuirian band profiles and the retention time varia tion trend. (C) 2000 Elsevier Science BN. All rights reserved.