Optimized separation of beta-blockers with multiple chiral centers using capillary electrochromatography-mass spectrometry.

This work focuses on the simultaneous analysis of beta-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.