title: Automated in-tube solid-phase microextraction coupled with liquid chromatography/electrospray ionization mass spectrometry for the determination of beta-blockers and metabolites in urine and serum samples.
abstract: The technique of automated in-tube solid-phase microextraction (SPME) coupled with liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) was evaluated for the determination of beta-blockers in urine and serum samples. In-tube SPME is an extraction technique for organic compounds in aqueous samples, in which analytes are extracted from the sample directly into an open tubular capillary by repeated draw/eject cycles of sample solution. LC/MS analyses of beta-blockers were initially performed by liquid injection onto a LC column. Nine beta-blockers tested in this study gave very simple ESI mass spectra, and strong signals corresponding to [M + H]+ were observed for all beta-blockers. The beta-blockers were separated with a Hypersil BDS C18 column using acetonitrile/methanol/water/acetic acid (15:15:70:1) as a mobile phase. To optimize the extraction of beta-blockers, several in-tube SPME parameters were examined. The optimum extraction conditions were 15 draw/eject cycles of 30 microL of sample in 100 mM Tris-HCl (pH 8.5) at a flow rate of 100 microL/min using an Omegawax 250 capillary (Supelco, Bellefonte, PA). The beta-blockers extracted by the capillary were easily desorbed by mobile-phase flow, and carryover of beta-blockers was not observed. Using in-tube SPME/LC/ESI-MS with selected ion monitoring, the calibration curves of beta-blockers were linear in the range from 2 to 100 ng/mL with correlation coefficients above 0.9982 (n = 18) and detection limits (S/N = 3) of 0.1-1.2 ng/mL. This method was successfully applied to the analysis of biological samples without interference peaks. The recoveries of beta-blockers spiked into human urine and serum samples were above 84 and 71%, respectively. A serum sample from a patient administrated propranolol was analyzed using this method and both propranolol and its metabolites were detected.
authors.affiliation: Department of Chemistry, University of Waterloo, Ontario, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Kataoka
authors.forename: S
authors.initials: S
authors.lastname: Narimatsu
authors.forename: H L
authors.initials: HL
authors.lastname: Lord
authors.forename: J
authors.initials: J
authors.lastname: Pawliszyn
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000097:blood* / Q000378:metabolism / Q000652:urine*; D001331:Automation; D002138:Calibration; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation; D002853:Chromatography, Liquid / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry / Q000379:methods*; D011433:Propranolol / Q000097:blood / Q000378:metabolism / Q000652:urine; D012680:Sensitivity and Specificity
chemical_list: D000319:Adrenergic beta-Antagonists; D011433:Propranolol