Abstract: The liquid chromatographic enantiomer separation of β-blockers on several polysaccharide derived chiral stationary phases (CSPs) (Chiralpak AD, Chiralcel OD, Chiralpak IA and Chiralpak IB) was performed and compared in the normal phase mode using hexane-ethanol in the presence of acid or base additives. The chromatographic conditions were 10%~30% (v/v) ethanol-hexane containing 0.1% trifluoroacetic acid or triethylamine as the mobile phase at the flow rate of 1.0 mL/min with the detection at 254 nm. The lower enantioselectivities and the shorter retention times on amylose derived CSPs (Chiralpak AD and Chiralpak IA) using the mobile phase with acid additive than those with base additive were shown, except for slightly longer retention times of metoprolol and propranolol on Chiralpak AD. The greater enantioselectivities and the shorter retention times on cellulose derived CSPs (Chiralcel OD and Chiralpak IB) using the mobile phase with acid additive than those with base additive were shown, especially, Chiralcel OD showed dramatically enhanced enantioselectivites using the mobile phase with acidic additive. Also, it was shown that the greater enantiomer separation of β-blockers on Chiralcel OD was achieved using the mobile phases with the higher concentration acid additive.

Key words: chiral stationary phases, enantiomer resolution, β-blockers , high performance liquid chromatography (HPLC)