Determination of β-Agonist Residues in Animal-Derived Food by a Liquid Chromatography-Tandem Mass Spectrometric Method Combined with Molecularly Imprinted Stir Bar Sorptive Extraction

Analysis of β-agonists in different biological matrices by liquid chromatography–tandem mass spectrometry

Introduction

Wide use is made of β-agonists in therapy due to their smooth muscle–relaxant properties. They also have a side effect of increasing muscle mass. Besides improving oxygen utilisation as bronchodilators, β-agonists increase protein synthesis and promote fat burning. The growth- and performance-enhancing effects are often exploited in illegal use. The guiding objective of this study was to develop a procedure for the determination of β-agonists by a single method in different types of matrices.

Material and Methods

Five grams of homogenised samples were subjected to enzymatic hydrolysis with β-glucuronidase in ammonium acetate, pH 5.2. Purification was performed by solid phase extraction. Analytes were eluted with 10% acetic acid in methanol. The eluted β-agonists were analysed by high-performance liquid chromatography–tandem mass spectrometry.

Results

Validation results met the requirement of the confirmation criteria according to European Commission Decision 2002/657/EC in terms of apparent recoveries (93.2–112.0%), repeatability (3.1–7.1%) and intra-laboratory reproducibility (4.1–8.2%).

Conclusion

The method can be successfully applied in the detection and determination of clenbuterol, salbutamol, mabuterol, mapenterol, terbutaline, brombuterol, zilpaterol, isoxsuprine and ractopamine in feed, drinking water, urine, muscle, lung and liver matrices.

Beta-agonist drugs modulate the proliferation and differentiation of skeletal muscle cells in vitro

Essentially employed for the treatment of airway obstructions in humans, β-agonists are also known to have an anabolic effect in animals’ skeletal muscle. In vivo and in vitro studies have attested the increase in animal body mass and the hypertrophy of muscle cells following the administration of specific β-agonists. However, the contribution of β-agonists to C2C12 myoblasts growth remains obscure. We therefore aimed to investigate the impact of β1-and β2-agonist drugs on the proliferation and differentiation of skeletal muscle cells. Direct observations and cytotoxicity assay showed that clenbuterol, salbutamol, cimaterol and ractopamine enhanced muscle cell growth and viability during the proliferation stage. Structural examinations coupled to Western blot analysis indicated that salbutamol and cimaterol triggered a decrease in myotube formation. A better comprehension of the effect of β-agonists on myogenic regulatory genes in the muscle cells is crucial to establish a specific role of β-agonists in muscle development, growth, and regeneration.

•

Clenbuterol, salbutamol, cimaterol, and ractopamine induce molecular responses in C2C12.

•

Beta-agonists promote cell's attachment, viability, and proliferation during muscle cell proliferation stage.

•

Salbutamol and cimaterol inhibit the formation of myotubes during differentiation stage.

Stir bar sorptive extraction and its application

Recent progress of stir bar sorptive extraction (SBSE) in the past six years is reviewed. The preparation methods including electrodeposition, self-assembly, solvent exchange, physical magnetic adsorption and electrostatic spinning, for the coated stir bar are summarized and compared, specifically for a specific material for coatings fabrication, e.g., carbon-based materials and metal organic frameworks. The emerging materials (e.g., graphene, graphene oxide, carbon nanotubes, monolith, metal-organic frameworks and porous organic polymers) applied for coated stir bar fabrication are one of the focus of this review, along with their respective advantages in extraction process and application in trace analysis. The development and application of extraction apparatus of SBSE are also involved. Based on these information, the development status and prospects of SBSE as an efficient sample pretreatment technique in real sample analysis are discussed.

Electrospray ionization rapid screening sans liquid chromatography column: A sensitive method for detection and quantification of chemicals in animal tissues and urine

RATIONALE

Electrospray ionization mass spectrometry (ESI-MS) in conjunction with liquid chromatography (LC) can provide accurate quantitative data, but it is not well-suited for the rapid screening (RS) of analytes incurred into complex matrices. This study was designed to determine the usefulness of ESI for rapid detection and quantitation of veterinary drugs from complex biological matrices under near real-time conditions.

METHODS

Nine veterinary drugs or metabolites, clenbuterol, erythromycin, flunixin, 5-hydroxyflunixin, meloxicam, ractopamine, salbutamol, tylosin and zilpaterol, present in cow urine, sheep urine, sheep tissues (kidney, muscle, liver and lung) or pig kidney, were simultaneously analyzed. A simple sample clean-up procedure, which included dilution with 10% sodium carbonate followed by extraction with ethyl acetate, was used. For tissues, an additional pre-extraction with hexane was performed to remove fat prior to MS analysis. Samples were introduced into the mass spectrometer through the LC autosampler, but no chromatographic separation was employed. A Sciex 5600+ triple time-of-flight mass spectrometer with a dual-spray source interfaced with a Shimadzu Nexera LC system was used. Samples were analyzed in positive ion mode.

RESULTS

Sample extraction times were typically 10-30 min or less and instrumental analysis time was 1 min/sample. Regression coefficients of matrix-matched standard curves across all compounds ranged from 0.9701-0.9999 in urine (cow and sheep) and tissues (sheep kidney, liver, lung, muscle and pig kidney). Limits of detection ranged from 0.11 to 2.03 ng/mL across analytes in urine and 0.11 to 8.86 ng/g across tissues. Correlations between RS-ESI-MS and LC/MS/MS results were 0.956 to 0.998 for incurred residues of flunixin in cow urine, ractopamine in pig kidney and zilpaterol in sheep urine.

CONCLUSIONS

RS-ESI-MS provided rapid, sensitive, and accurate analyses of nine veterinary drugs from complex matrices with very little sample preparation and produced quantitative data akin to LC/MS/MS.

Facile synthesis of magnetic sulfonated covalent organic framework composites for simultaneous dispersive solid-phase extraction and determination of β-agonists and fluoroquinolones in food samples

In this work, an efficient method for the determination of β-agonists and fluoroquinolones was established, based on a mixed-mode sorbent of magnetic sulfonated covalent organic framework composites. By coupling with HPLC-MS/MS, the main factors that affect the extraction procedure were optimized. Under the optimal conditions, the proposed HPLC-MS/MS method was successfully utilized for the extraction of β-agonists and fluoroquinolones in milk and pork meat samples. The method showed good linearities (R² ≥ 0.9916), and low LOQs of 0.1-0.2 ng g^-1 for β-agonists and fluoroquinolones. The adsorption mechanism was investigated with the assistance of quantum chemistry calculation method, and it is worth noting that the sorbent relied mainly on the multiple adsorption mechanisms, including π-π stacking, hydrophobic, electrostatic attraction and hydrogen-bonding interactions. This work not only provides a simple method for the preparation of a mixed-mode sorbent, but also a routine analysis strategy for monitoring the illegal use of β-agonists and fluoroquinolones.

Application of molecularly imprinted polymers in the anti-doping field: sample purification and compound analysis

The problem posed by anti-doping requirements is one of the great analytical challenges; multiple compound detection at low ng ml-1 levels from complex samples, with requirements for exceptional confidence in results. This review surveys the design, synthesis and application of molecularly imprinted polymers (MIPs) in this field, focusing on the templating of androgenous anabolic steroids (AASs), as the most commonly abused substances, but also other WADA prohibited substances. Commentary on the application of these materials in detection, clean-up and sensing is offered, alongside views on the future of imprinting in this field.

Application of the Mechanical High-Pressure Method Combined with High-Performance Liquid Chromatography-Tandem Mass Spectrometry for Determination of Veterinary Drug Residues in Incurred Chicken and Rabbit Muscle Tissues

Rapid sample preparation is a key step in the field of food safety. A mechanical high-pressure method using a laboratory-made meat press machine was first introduced in this study to process the incurred muscle samples of chicken and rabbit. By applying high pressure to animal muscle, the meat juice was obtained. After extraction and purification, veterinary drug residues in the juice were qualitatively and quantitatively analyzed by using high-performance liquid chromatography-tandem mass spectrometry. The sample press conditions and extraction solvents were optimized. Under the optimal conditions, all veterinary drug residues, including tetracycline, enrofloxacin, clenbuterol, ampicillin, lincomycin, erythromycin, and sulfadiazine, in the incurred samples were detected. The residual concentration of drugs in samples obtained by using the mechanical high-pressure method can reach up to 94.0% of that obtained by using the common homogenization method, suggesting that drug residues exist in the tissue juice, which justifies the use of the mechanical high-pressure method. Moreover, with the mechanical high-pressure method, the sample preparation time was shortened by five times, and the consumption of the extraction solvent was reduced by 50%, relative to the homogenization method.