Detection of Glucocorticoid Residues in Animal- derived Food by HPLC-MS/MS

Importance of the topic

Glucocorticoid residues in food of animal origin represent a significant public health concern due to their potent anti‐inflammatory and immunosuppressive effects. Regulatory limits have been established worldwide to protect consumers, and reliable analytical methods are essential for monitoring compliance and ensuring food safety.

Goals and overview

This application note describes the development and validation of a highly sensitive LC‐MS/MS method for simultaneous detection of eight glucocorticoids in diverse animal‐derived matrices, including muscle, liver, kidney, milk, eggs, and poultry tissues. The method is designed to meet or exceed maximum residue limits set by the European Commission and Chinese authorities.

Methodology and instrumentation

Sample preparation involves:

• Weighing 2 g of tissue or equivalent volume of liquid matrix.
• Liquid–liquid extraction with ethyl acetate and 0.1 M NaOH.
• SPE cleanup on silica cartridges conditioned with n-hexane.
• Evaporation under nitrogen at 40 °C and reconstitution in 20 % acetonitrile.

The LC-MS/MS setup comprises:

• Thermo Scientific Surveyor HPLC with Hypersil GOLD column (150 × 2.1 mm, 5 µm) and gradient elution (water/0.1 % formic acid and acetonitrile).
• Thermo Scientific TSQ Quantum triple quadrupole with ESI source operating in negative ion mode.
• SRM monitoring of quantitative and qualitative transitions for each glucocorticoid.

Main results and discussion

The method achieved:

• Limits of quantitation between 0.1 and 0.5 µg/kg (or µg/L), surpassing regulatory requirements.
• Linear dynamic ranges up to 200 µg/kg with correlation coefficients (R²) above 0.99.
• Extraction recoveries of 60–110 % across all matrices, ensuring accuracy and precision.
• Robust reproducibility with 1/x weighted calibration and SRM specificity.

Benefits and practical applications

This validated protocol offers:

• High throughput screening and quantification of multiple glucocorticoids in a single run.
• Compliance with European and Chinese maximum residue levels.
• Applicability to regulatory, quality‐assurance, and veterinary diagnostic laboratories.

Future trends and possibilities

Emerging developments include integration of high‐resolution mass spectrometry for non‐targeted screening, automation of sample preparation workflows, and expansion to additional veterinary drug classes. On‐site portable MS instruments may further accelerate real‐time monitoring at production sites.

Conclusion

The described LC‐MS/MS method demonstrates excellent sensitivity, selectivity, and reproducibility for eight glucocorticoid residues in various food matrices. It fulfills international regulatory criteria and supports routine surveillance to safeguard public health.

Reference

• 1. European Community, Council Directive 96/22/EC, Official Journal L125, 23 May 1996, pp. 3–9.
• 2. European Commission Regulation (EC) No 508/1999, Official Journal L060, 9 March 1999, pp. 16–52.
• 3. European Commission Regulation (EC) No 2593/1999, Official Journal L315, 8 December 1999, pp. 26–31.
• 4. European Commission Regulation (EC) No 2535/2000, Official Journal L291, 17 November 2000, pp. 9–10.
• 5. European Commission Regulation (EC) No 77/2002, Official Journal L016, 17 January 2002, pp. 9–11.