Enantiomeric separation of propranolol by normal phase chiral liquid chromatography coupled with tandem mass spectrometry

A rapid and sensitive method was developed and validated using a normal phase liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for determination of propranolol enantiomers in pharmaceuticals. Sample preparation involved a single extraction step by the addition of methanol. Separation of propranolol enantiomers was achieved on a Chiralcel OD-H chiral column using a mobile phase consisting of n-hexane-ethanol-ammonia (70:30:0.4, v/v/v), and the flow rate was 0.40 mL/min for 20 min. The analyte was monitored by tandem mass spectrometry with electrospray positive ionization in multiple reaction monitoring (MRM) mode, using the transitions of m/z 260.2 --> 116.0. Propranolol enantiomers can be completely separated. The linear range was 2.5-1000 microg/L, and the limit of quantification (LOQ) was 2.5 microg/L. The values for within day and between day precisions and accuracies were well within the generally accepted criteria for analytical methods. The relative standard deviations (RSDs) were less than 2.64%, and the recoveries of the two enantiomers were 99.08%-102.58% and 100.21%-103.16%, respectively. The separation method is accurate, convenient, reliable, efficient, and can be subsequently used for quality control of propranolol enantiomers in pharmaceuticals.