EuroResidue: MULTI-RESIDUE SCREENING APPROACH FOR THE DETECTION OF VETERINARY DRUGS IN ANIMAL TISSUES USING LC-MS/MS

Importance of the Topic

The use of veterinary drugs in livestock production is critical for animal health but raises concerns when residues remain in edible tissues.
Ensuring consumer safety and regulatory compliance requires sensitive, high-throughput analytical methods capable of screening multiple drug classes simultaneously.
LC-MS/MS technology offers selectivity and sensitivity that can minimize extensive sample cleanup and accelerate routine monitoring.

Objectives and Study Overview

This study aimed to develop and validate a generic multi-residue screening method for over 150 veterinary drugs in animal muscle tissues.
The goals included establishing detection capabilities below or in line with maximum residue limits (MRLs) and demonstrating compliance with EU Commission Decision 2002/657/EC screening criteria.
Method performance was assessed using spiked and blank samples from bovine, porcine, and turkey muscle.

Methodology and Instrumentation

Sample Preparation:

• Minced muscle tissue sourced from bovine, porcine, and turkey specimens.
• Generic liquid extraction using oxalic acid in acetonitrile followed by dispersive solid-phase extraction (dSPE) cleanup.
• Extracts stored at –20 °C and analyzed within 48 hours to preserve analyte stability.

Chromatographic Conditions:

• System: UPLC I-Class Plus with in-line filter.
• Column: ACQUITY UPLC HSS T3 (2.1 × 100 mm).
• Mobile phase A: 0.1 % formic acid with 0.1 mM ammonium formate (aqueous).
• Mobile phase B: 0.1 % formic acid in 50/50 methanol/acetonitrile.
• Injection volume: 1 µL; column temperature: 40 °C; total run time: 15 min.

Mass Spectrometry:

• Instrument: Waters Xevo TQ-XS triple quadrupole.
• Ionization: Electrospray in positive/negative mode with polarity switching.
• Acquisition: Multiple reaction monitoring (MRM) with optimized transitions.

Results and Discussion

The method was validated over three independent batches using matrix-matched calibration curves and spiked blank tissues.
Detection capability (CCß) was calculated by comparing a threshold (T) for positive samples against a cut-off factor (Fm) for negatives in line with EU guidelines.
Ciprofloxacin served as an example analyte, with CCß established at 0.1 µg/kg and confirmed at 1 µg/kg.
Overall, more than 70 % of the veterinary drugs screened achieved CCß values at or below 1 µg/kg, and almost all analytes surpassed required MRL criteria.

Benefits and Practical Applications

The workflow combines a single-step extraction with minimal cleanup, reducing hands-on time and solvent usage.
Low injection volume limits matrix load to the MS and extends column life.
Fast 15-minute chromatographic cycle supports high sample throughput.
The approach meets or exceeds regulatory screening limits for a broad range of veterinary drug classes.

Future Trends and Applications

Expansion of the analyte panel to include additional drug classes and key metabolites.
Adoption of high-resolution mass spectrometry for confirmatory analysis and non-targeted screening.
Automation of sample preparation steps to further increase throughput and reduce variability.
Development of field-deployable or portable MS systems for on-site rapid screening in abattoirs and processing plants.

Conclusion

A robust LC-MS/MS screening method has been established for the simultaneous detection of over 150 veterinary drugs in animal muscle tissues.
The protocol demonstrates high sensitivity, streamlined sample processing, and compliance with EU Commission Decision 2002/657/EC screening requirements.
This approach supports effective residue monitoring programs, contributing to food safety and regulatory oversight.

Reference

• Adams S, Hird S. Multi-residue screening approach for the detection of veterinary drugs in animal tissues using LC-MS/MS. Waters Corporation, Wilmslow, UK; 2022.