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  • 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.

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.

Analytical chemistry (1999-10-12)
H Kataoka, S Narimatsu, H L Lord, J Pawliszyn
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.

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Supelco
Omegawax Capillary GC Column, L × I.D. 30 m × 0.32 mm, df 0.25 μm
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Supelco
Omegawax Capillary GC Column, L × I.D. 30 m × 0.25 mm, df 0.25 μm
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Supelco
Omegawax Capillary GC Column, L × I.D. 15 m × 0.10 mm, df 0.10 μm
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