Automated In-Tube Solid-Phase Microextraction Coupled with Liquid Chromatography/Electrospray Ionization Mass Spectrometry for the Determination of β-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.

Analysis of estrogens in environmental waters using polymer monolith in-polyether ether ketone tube solid-phase microextraction combined with high-performance liquid chromatography

“…By integrating sample extraction, preconcentration and introduction into one single step, this on-line method can provide better accuracy, precision, and sensitivity than those off-line methods. With the use of an autosampler, automation was even achieved [41]. Mitani applied this automatic technique to the determination of five estrogens in environmental water samples using a Supel-Q porous layer open tubular (PLOT, porous divinylbenzene polymer) capillary column as the extraction medium [35].…”

High speed determination of beta‐receptor blocking agents in human urine by liquid chromatography/tandem mass spectrometry

“…The developments in interfacing liquid chromatography to mass spectrometry, eg electrospray ionization and atmospheric pressure chemical ionization, allow sensitive detection of these substances extracted from human urine or blood plasma without further derivatization as demonstrated in other studies dealing with b-blocker analysis (Abdel-Hamid, 2000;Kataoka et al, 1999;Beaudry et al, 1999;Gergov et al, 2000). They describe the LC/MS detection of the most common 16 drugs in this field, but the huge variety present in the international market requires procedures enabling the identification of more of these compounds.…”

Sample preparation with fiber-in-tube solid-phase microextraction for capillary electrophoretic separation of tricyclic antidepressant drugs in human urine

“…Recently, the in-tube SPME method, which could be coupled directly to LC, was developed [11,12]. As the extraction medium, a commercially available open-tubular capillary gas chromatography (GC) column has generally been employed in this sample preconcentration technique.…”