Study of β-agonist Residues in Animal-derived Foods by LC-MS/MS

Importance of the Topic

Beta-adrenoceptor agonists are bronchodilators that also exhibit anabolic properties, making them illicit growth promoters in livestock. Their presence in food poses significant health risks, prompting international bans and strict monitoring requirements to protect public health.

Study Objectives and Overview

The aim of this study was to establish a robust LC-MS/MS method for simultaneous detection and quantification of ten β-agonists in animal-derived foods (liver, pork, milk, eggs). The target analytes included cimaterol, clenbuterol, clorprenaline hydrochloride, fenoterol, pentubutolol, propranolol, ractopamine, salbutamol, terbutaline, and tulobuterol.

Methodology and Instrumentation

Sample Preparation

• Weighed 2 g of homogenized tissue or equivalent liquid sample.
• Extracted with 10 mL of 0.2 M ammonium acetate (pH 5.2) and added β-glucosidase/arylsulfatase for hydrolysis (37 °C, 16 h).
• After centrifugation, supernatant was acidified with perchloric acid, centrifuged, and applied to conditioned SPE cartridges.
• Analytes were eluted with 5% ammonium hydroxide in methanol, evaporated under nitrogen, and reconstituted in 20% acetonitrile aqueous solution.

Used Instrumentation

• HPLC: Thermo Scientific Surveyor system with Hypersil GOLD column (150 × 2.1 mm, 5 µm).
• Mobile Phases: A = 5 mM ammonium acetate in water; B = methanol; gradient from 10% to 90% B over 5 min; total run 12 min; flow rate 250 µL/min.
• Mass Spectrometry: Thermo Scientific TSQ Quantum triple quadrupole with ESI source in positive ion mode. Key settings: spray voltage 4500 V; sheath gas 30 units; auxiliary gas 5 units; capillary temperature 350 °C; collision gas (Ar) 1.5 mTorr.
• Detection: Selected reaction monitoring (SRM) transitions optimized for each analyte.

Main Results and Discussion

The method achieved limits of quantitation of 0.1 µg/kg for eight β-agonists and 0.5 µg/kg for cimaterol and terbutaline in all matrices. Extraction recoveries ranged from 75% to 120%, meeting international validation criteria. Representative SRM chromatograms demonstrated good peak shape and separation at 1 ng/mL.

Benefits and Practical Applications

This LC-MS/MS approach provides high sensitivity, reproducibility, and throughput for routine monitoring of β-agonist residues. It supports regulatory compliance in food safety laboratories and can be integrated into quality assurance protocols across the meat, dairy, and egg industries.

Future Trends and Applications

Advances may include integration of high-resolution mass spectrometry for non-targeted screening, automation of sample preparation to increase throughput, and expansion to multi-class veterinary drug panels. Continuous improvement in software algorithms will enhance data processing and detection capabilities.

Conclusion

The developed LC-MS/MS method reliably quantifies ten β-agonists in diverse animal-derived foods with excellent sensitivity and reproducibility, aligning with international regulatory requirements.

Reference

1. European Community, Council Directive 96/22/EC concerning the prohibition on the use in stockfarming of certain substances having hormonal or thyrostatic action and of β-agonists, Official Journal L 125, 23 May 1996, pp. 3–9.