Targeted Veterinary Drug Screening in Food Matrices Using EMR—Lipid QuEChERS Kit and an Agilent 6470A Triple Quadrupole LC/MS System

Importance of the Topic

Monitoring veterinary drug residues in edible tissues is critical to ensure food safety, protect public health, and comply with international maximum residue limits (MRLs). Lipophilic compounds and their metabolites can accumulate in fatty matrices and enter the human food chain, requiring highly sensitive and selective analytical workflows.

Objectives and Study Overview

This study demonstrates a targeted screening and quantitation method for 105 veterinary drugs in beef, beef liver, pork, and salmon. It evaluates the combination of an Enhanced Matrix Removal—Lipid (EMR—Lipid) QuEChERS sample preparation kit with an Agilent 6470A Triple Quadrupole LC/MS system to achieve regulatory compliance at trace levels.

Methodology and Instrumentation

Samples were homogenized and spiked at nine concentration levels (0.1–100 ng/g). Lipid removal was performed using the Agilent EMR—Lipid QuEChERS kit to minimize matrix interferences. Chromatographic separation employed an Agilent 1290 Infinity UHPLC with a PoroShell 120 EC-C18 column (2.1×150 mm, 2.7 μm) under a gradient of 0.5 mM NH4F/0.1% formic acid in water (A) and acetonitrile with 0.1% formic acid (B). Detection utilized dynamic multiple reaction monitoring (dMRM) on an Agilent 6470A Triple Quadrupole with Jet Stream ESI, using polarity switching and two optimized transitions per analyte. Data processing was conducted with Agilent MassHunter Quantitative Analysis (v B.07).

Main Results and Discussion

Efficient lipid removal improved signal clarity and sensitivity. At a 1 ng/g spike, all 105 analytes produced well-defined peaks in beef and pork, the most challenging matrices. The majority of compounds achieved limits of quantitation (LLOQs) as low as 0.1 ng/g, with signal-to-noise ratios above 10. Accuracy data show that up to 73 compounds in beef and 58 in pork met 80–120% recovery at their LLOQ levels. Precision across six replicates yielded percent relative standard deviations (%RSD) below 10% for most analytes. Calibration curves over 0.1–100 ng/g were linear (R2>0.99) for over 96% of target drugs; a few required quadratic fits due to low-end losses or high-end saturation. Analysis of market samples revealed trace residues of ractopamine, monensin, robenidine, and ketoprofen in beef and salmon at sub-regulatory levels.

Benefits and Practical Applications

The integrated EMR—Lipid QuEChERS and 6470A LC/TQ platform offers a fast, robust, and high-throughput solution for comprehensive veterinary drug monitoring in fatty tissues. Key advantages include streamlined sample prep, enhanced analyte recovery, minimized matrix effects, and compliance with global residue regulations. This workflow supports quality assurance laboratories and regulatory agencies in routine surveillance and method validation.

Future Trends and Potential Applications

Advancements may include automation of QuEChERS protocols, expansion of compound libraries to cover emerging veterinary drugs, and integration with high-resolution mass spectrometry for non-targeted screening. Further development of green solvents and miniaturized extraction formats will enhance sustainability. Data analytics and cloud-based platforms will enable real-time monitoring and collaborative data sharing across laboratories.

Conclusion

The combined EMR—Lipid QuEChERS and Agilent 6470A Triple Quadrupole LC/MS system provides a powerful, sensitive, and reliable approach for the targeted screening of 105 veterinary drugs at or below established MRLs in complex food matrices. The method delivers excellent accuracy, precision, linearity, and throughput, supporting regulatory compliance and food safety monitoring.

References

1. USDA FSIS and Codex Alimentarius maximum residue standards.
2. Codex CAC/MRL 2-2015, FAO/WHO.
3. Zhao L., Lucas D. Agilent Application Note 5991-6096EN.
4. Stevens J. Agilent Application Note 5991-6771EN.