Penicillin G as a novel chiral selector in capillary electrophoresis

• Penicillin G was evaluated as an ion-pair chiral selector in enantioseparation by CE.
• Effects of separation conditions for basic chiral analytes were investigated.
• Optimal mobile phase conditions for chiral separations were found.

The penicillin sub-class of β-lactam antibiotics has not been examined for its enantiodiscriminating abilities in capillary electrophoresis (CE) until date. The present work was therefore designed to evaluate penicillin G potassium salt (PenG) as an ion-pair chiral selector (CS) using CE for its several attributes, namely, high solubility in water and lower alcohols, structure allowing multiple interactions with analytes and cost-effectiveness. Systematic experiments were performed to investigate the effect of composition of background electrolyte, applied voltage and capillary temperature on chiral separation. Baseline resolutions of enantiomers of five basic chiral drugs (namely, darifenacin, citalopram, sertraline, propranolol and metoprolol) were attained using a background electrolyte composed of water:methanol (90:10, v/v) and consisting of 10.7 or 16.1 mM CS at 20 °C using an applied voltage of 5 kV.