Optimized separation of β-blockers with multiple chiral centers using capillary electrochromatography–mass spectrometry

This work focuses on the simultaneous analysis of β-blockers with multiple stereogenic centers using capillary electrochromatography–mass spectrometry (CEC–MS) with a vancomycin stationary phase. The critical mobile phase variables (composition of organic solvents, acid/base ratios) as well as column temperature and electric field strength, effecting enantioresolution and analysis time were first optimized sequentially. Next, to achieve global optimum a multivariate D-optimal design was used. Although multivariate approach did not improve enantioresolution any further, analysis time was significantly reduced. Under optimum CEC–MS conditions, all stereoisomers were resolved with resolution in the range 1.0–3.1 in less than 60 min with an average signal-to-noise (S/N) greater than 1000. The developed CEC–MS method has the potential to emerge as a screening method for analysis of multiple chiral compounds using a single protocol using the same column and mobile phase conditions, thus reducing the operation time and cost.