Sequential optimization of mobile phase composition for the simultaneous enantioseparation of nadolol (N1, N2, N3, N4) and labetalol (L1, L2, L3, L4). Mobile phase with variable amounts of methanol and acetonitrile with acetic acid and triethylamine held constant at 1.6 and 0.2% (v/v), respectively. Experimental conditions: 70 cm column (i.d. 75 μm) packed with 60 cm of VCSP; CEC electric field strength and temperature: 417 V/cm and 25 °C. Sheath liquid: 90/10 MeOH/ACN 50 mM NH4OAc; spray chamber: drying gas flow rate: 5 L/min, drying gas temperature: 130 °C, nebulizer pressure: 4 psi.