title: Analysis of beta-agonists and beta-blockers in urine using hollow fibre-protected liquid-phase microextraction with in situ derivatization followed by gas chromatography/mass spectrometry.
abstract: A method using hollow fibre-protected liquid-phase microextraction (HF-LPME) with in situ derivatization followed by gas chromatography/mass spectrometry (GC/MS) was established for the analysis of beta-agonists and beta-blockers in urine. Because it can simultaneously extract and derivatize compounds of interest by methylbenzol and N-methyl-N-(trimethylsilyl) trifluoroacetamide (MSTFA) in HF-LPME, the approach overcomes the drawbacks of considerable time-consuming and tedious operation, meanwhile improves enrichment multiple. The optimized conditions were extraction for 20 min at 35 degrees C with 5.0 microL of mixed extraction solvent (methylbenzol/MSTFA=1:1, v/v) with stirring speed of 925 rpm in 5.0 mL sample under pH 12.0 and 14% (w/v) NaCl. The method provided very wide linear ranges (0.25-400 ng mL(-1)) and low detection limits in the range of 0.08-0.10 ng mL(-1) for clenbuterol, metoprolol and propranolol while enrichment factors reached up to 256. The analytes could be determined in spiked urine by the method with high extraction efficacy (93.79-109.04% recoveries) and precision (<9.70% RSD). It has a satisfactory result for metoprolol in practical human urine samples for a single-dose administration of 50 mg after 36 h. The proposed method only needs few microliters of organic solvent and derivatizing agent; the operation is simple, convenient and rapid for the trace analysis of beta-agonists and beta-blockers in biological fluids; it can be readily generalized for high sample throughput. So, it is hopeful that the study will facilitate the monitoring of beta-agonists and beta-blockers in the competition sports.
authors.affiliation: The Sport Science Research Center, Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fuzhou University, Fuzhou, Fujian 350002, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.forename: Zhenyi
authors.initials: Z
authors.lastname: Wei
authors.forename: Shengping
authors.initials: S
authors.lastname: Chen
authors.forename: Guonan
authors.initials: G
authors.lastname: Chen
mesh_terms: D000318:Adrenergic beta-Agonists / Q000652:urine*; D000319:Adrenergic beta-Antagonists / Q000652:urine*; D005591:Chemical Fractionation / Q000379:methods*; D002976:Clenbuterol / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D016014:Linear Models; D008790:Metoprolol / Q000652:urine; D011433:Propranolol / Q000652:urine; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012965:Sodium Chloride / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D013696:Temperature
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D012997:Solvents; D012965:Sodium Chloride; D011433:Propranolol; D008790:Metoprolol; D002976:Clenbuterol