title: Simultaneous enantioseparation and tandem UV-MS detection of eight beta-blockers in micellar electrokinetic chromatography using a chiral molecular micelle.
abstract: The feasibility of using a new and more versatile polymeric chiral surfactant, i.e., poly(sodium N-undecenoxy carbonyl-L-leucinate (poly-L-SUCL) is investigated for simultaneous enantioseparation and detection of eight structurally similar beta-blockers with tandem UV and MS detection. Three optimization approaches, i.e., direct infusion-MS, capillary zone electrophoresis-MS, and chiral micellar electrokinetic chromatography-mass spectrometry (CMEKC-MS), were investigated to optimize sheath liquid parameters, spray chamber parameters, and CMEKC separation parameters for maximum sensitivity and chiral resolution. Compared to unpolymerized micelle of L-SUCL, the use of micelle polymer (i.e., poly-L-SUCL) provided significantly higher separation efficiency, lower separation current, and higher detection sensitivity for CMEKC-ESI-MS of beta-blockers. It was also observed that, unlike monomeric L-SUCL, polymeric L-SUCL provided enantioseparation of all beta-blockers even at the lowest surfactant concentration (i.e., 5 mM poly-L-SUCL). Under optimum CMEKC and ESI-MS conditions (15 mM poly-L-SUCL, 25 mM each of NH4OAc and TEA (pH 8.0); 80% (v/v) methanol sheath liquid containing 40 mM NH4OAc (pH 8.0); sheath liquid flow rate, 5.0 microL/min; drying gas flow rate, 5 L/min; drying gas temperature, 200 degrees C; nebulizing pressure, 6 psi (0.414 bar); capillary voltage, +2.5 kV; fragmentor voltage, 85 V), baseline enantioseparation of eight beta-blockers was achieved by tandem UV (in approximately 30 min) and MS (in approximately 60 min) detection. Calibration curves for all beta-blockers were linear in the range of 0.01-0.6 mM for both CMEKC-UV and CMEKC-MS methods, but the later method provided better concentration limit of detection with similar RSD for migration time and peak areas. The CMEKC-ESI-MS method appears suitable for use as a routine procedure for high-throughput separation of beta-blockers with high sensitivity.
authors.affiliation: Department of Natural Sciences, Fayetteville State University, Fayetteville, North Carolina 28301, USA.
authors.forename: Cevdet
authors.initials: C
authors.lastname: Akbay
authors.forename: Syed A A
authors.initials: SA
authors.lastname: Rizvi
authors.forename: Shahab A
authors.initials: SA
authors.lastname: Shamsi
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000032:analysis*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D009994:Osmolar Concentration; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013237:Stereoisomerism; D013501:Surface-Active Agents
chemical_list: D000319:Adrenergic beta-Antagonists; D008823:Micelles; D013501:Surface-Active Agents