Development of a Efficient and Sensitive Dispersive Liquid-Liquid Microextraction Technique for Extraction and Preconcentration of 10 β2-Agonists in Animal Urine

Dispersive liquid–liquid microextraction (DLLME) coupled with ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) was developed for the extraction and determination of 10 β₂-agonists in animal urine. Some experimental parameters, such as the type and volume of the extraction solvent, the concentration of the dispersant, the salt concentration, the pH value of the sample solution, the extraction time and the speed of centrifugation, were investigated and optimized. Under the optimized conditions, a good enrichment factors (4.8 to 32.3) were obtained for the extraction. The enrichment factor show that the concentration rate of DLLME is significantly higher than other pretreatment methods, and the detection sensitivity has been greatly improved. The calibration curves were linear, the correlation coefficient ranged from 0.9928 to 0.9999 for the concentration range of 0.05 to 50 ngmL^-1 and 0.1 to 50 ngmL^-1, and the relative standard deviations (RSDs, n = 15, intra and inter-day precision) at a concentration of 5 ngmL^-1 were in the range of 1.8 to 14.6%. The limits of detection (LODs) for the 10 β₂-agonists, based on a signal-to-noise ratio (S/N) of 3, were in the range of 0.01 to 0.03 ngmL^-1. The proposed method was used to identify β₂-agonists in three types of animal urine (swine, cattle, sheep), and the relative recoveries from each matrix were in the range of 89.2 to 106.8%, 90.0 to 109.8% and 89.2 to 107.2%, respectively.

Rapid Determination of Clenbuterol in Pork by Direct Immersion Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry

Direct immersion solid-phase microextraction (DI-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) was developed for rapid analysis of clenbuterol in pork for the first time. In this work, a low-cost homemade 44 µm polydimethylsiloxane (PDMS) SPME fiber was employed to extract clenbuterol in pork. After extraction, derivatization was performed by suspending the fiber in the headspace of the 2 mL sample vial saturated with a vapor of 100 µL hexamethyldisilazane. Lastly, the fiber was directly introduced to GC-MS for analysis. All parameters that influenced absorption (extraction time), derivatization (derivatization reagent, time and temperature) and desorption (desorption time) were optimized. Under optimized conditions, the method offered a wide linear range (10-1000 ng g(-1)) and a low detection limit (3.6 ng g(-1)). Finally, the method was successfully applied in the analysis of pork from the market, and recoveries of the method for spiked pork were 97.4-105.7%. Compared with the traditional solvent extraction method, the proposed method was much cheaper and fast.

Identification of nuclear factor-κB inhibitors and β2 adrenergic receptor agonists in Chinese medicinal preparation Fuzilizhong pills using UPLC with quadrupole time-of-flight MS

INTRODUCTION

Fuzilizhong Pills (FZLZ), a modified form of a famous traditional Chinese medicine (TCM) Lizhong Wan in Treatise on Febrile Diseases and consisting of Panax ginseng C.A.Mey. (Ren Shen), Aconitum carmichaelii Debx. (Fu Zi, Zhi), Glycyrrhiza uralensis Fisch., Glycyrrhiza inflata Bat. or Glycyrrhiza glabra L. (Gan Cao), Atractylodes macrocephala Koidz. (Bai Zhu) and Zingiber offcinale Rosc. (Gan Jiang), show strong clinical therapeutic effects for dyspnea and pulmonary oedema. However, the bioactive compounds are still unclear. In this study, FZLZ was analysed using a rapid detection method to identify its anti-inflammatory and spasmolytic constituents.

OBJECTIVE

To develop a simple screening method to detect the anti-inflammatory and spasmolytic constituents of FZLZ.

METHODS

Ultra-performance liquid chromatography with quadrupole time-of-flight mass spectrometry combined with dual-bioactive (NF-κB and β2 -adrenergic receptor) luciferase reporter assay systems was employed.

RESULTS

Two β2 -adrenergic receptor agonists (salsolinol and higeramine) and three terpenoidal analogues of NF-κB inhibitors such as ginsenosides derivatives, triperpenoids derivatives and diester-diterpenoid aconitum alkaloid derivatives were characterised. Mesaconitine, flaconitine, ginsenosides Rb2, Rf, Rg2, F1 and Ro were considered to be new NF-κB inhibitors. Furthermore, IL-8 detection by enzyme linked immunosorbent assay confirmed the anti-inflammatory effects of the potential NF-κB inhibitors.

CONCLUSION

Compared with conventional fingerprints, activity-integrated fingerprints that contain both chemical and bioactive details offer a more comprehensive understanding of the chemical composition of plant materials. This strategy clearly demonstrated that dual bioactivity-integrated fingerprinting is a powerful tool for the improved screening and identification of potential dual-target lead compounds in complex herbal medicines.