Fast Quantitative Analysis of Aminoglycoside Antibiotic Residues in Meat, Eggs and Milk and Identity Confirmation with MRM Spectrum Mode

Importance of the Topic

Aminoglycoside antibiotics are extensively used in livestock and poultry to combat bacterial infections. Their persistence in edible tissues and products poses health risks due to nephro- and ototoxicity. Reliable, fast, and sensitive analytical methods are therefore critical to ensure food safety and regulatory compliance.

Objectives and Study Overview

This study evaluates a comprehensive Method Package for rapid quantitative analysis of 14 aminoglycosides in meat and milk, coupled with confirmatory identification using Multiple Reaction Monitoring (MRM) Spectrum mode. The aim is to demonstrate method performance against Japanese Maximum Residue Limits (MRLs) and a default limit for unregulated compounds.

Methodology and Instrumentation

• Sample Preparation: Five-gram aliquots of ground meat (beef, pork, chicken) or cow’s milk spiked at 0.5× and 1.5× MRL were extracted twice with acidic buffer containing ribostamycin as internal standard. Purification was conducted via weak-cation exchange and samples were diluted fivefold prior to injection.
• Chromatography: Hydrophilic Interaction Liquid Chromatography (HILIC) with an acetonitrile/formate buffer gradient; analysis cycle time of 4.5 minutes.
• Mass Spectrometry: Triple quadrupole detection on a Shimadzu LCMS-8060 in MRM mode using two transitions per analyte for quantitation. A secondary method records 15 MRM transitions per compound for spectral confirmation without changing reagents.
• Instrumentation: Shimadzu Nexera X2 UHPLC interfaced with LCMS-8060; data acquisition and library screening performed with LabSolutions Insight v.3.1.

Main Results and Discussion

Calibration curves spanned 10–150% of the highest MRL (or default 10 μg/kg), achieving accuracy within 85–115%. Unspiked samples showed no detectable residues. Recoveries in spiked meat and milk ranged from 70% to 120%, and repeatability in beef at 0.5× MRL yielded %RSD below 20%. MRM Spectrum library searches provided high identification scores (e.g., 95 for dihydrostreptomycin) distinguishing close analogues.

Benefits and Practical Applications

• High throughput with sub-5-minute analysis per sample.
• Elimination of ion-pairing reagents reduces system carryover and maintenance.
• Quantitation without matrix-matched calibration simplifies workflow.
• Applicability across diverse food matrices (meat cuts, poultry, milk).
• Built-in confirmatory step enhances confidence for over-limit findings.

Future Trends and Potential Applications

Advances may include coupling with high-resolution mass spectrometry for non-target screening, expansion of spectral libraries, automated sample preparation, miniaturized extraction, and adaptation to other polar veterinary drugs or environmental contaminants. Alignment with evolving global residue regulations will further broaden applicability.

Conclusion

The Shimadzu Method Package offers a robust, fast, and reliable solution for quantifying and confirming aminoglycoside residues in food products. Its high sensitivity, accuracy, and streamlined workflow make it well suited for routine monitoring in QA/QC and regulatory laboratories.