Multi-residue Automated Turbulent Flow Online LC-MS/MS Method for the Determination of Antibiotics in Milk

Significance of Topic

Antibiotic residues in dairy products pose health risks and are strictly regulated by the EU. A multi-residue analytical method offers efficient monitoring to ensure compliance with MRLs and protect consumers.

Objectives and Overview

This study aims to develop and validate a rapid, cost-effective automated analytical workflow for the simultaneous quantification of 36 antibiotic compounds spanning seven classes in milk. The approach integrates online turbulent flow sample cleanup with LC-MS/MS detection to meet legislative and quality control requirements.

Methodology and Instrumentation

Milk samples are homogenized and extracted with acetonitrile, followed by centrifugation and filtration. An internal standard is added prior to analysis. The automated setup couples a TurboFlow Cyclone P column and a phenyl-hexyl analytical column in an online TLX-LC system operated under a multistep gradient. A Thermo Scientific TSQ Quantum Access MAX triple quadrupole mass spectrometer in positive ESI-MRM mode provides selective detection. Data acquisition and quantification use matrix-matched calibration and internal standardization.

Main Results and Discussion

Validation according to EU 2002/657/EC demonstrated LOD and LOQ values below regulated MRLs for all analytes. Recoveries ranged from 78 to 120% across spike levels, with repeatability RSD between 4 and 28%. CCα and CCβ values were within acceptance criteria. Certified reference material analysis confirmed method accuracy for oxytetracycline.

Benefits and Practical Applications

This automated LC-MS/MS workflow reduces manual sample preparation, increases throughput, and delivers high sensitivity and specificity for multiple antibiotic residues in a single run. It is well suited for routine screening and confirmatory testing in food safety laboratories.

Future Trends and Possibilities

Emerging directions include expanding target compound panels, integration of high-resolution mass spectrometry for non-target screening, further automation with robotic sample handling, and application of chemometric and machine learning tools for data interpretation.

Conclusion

The developed multi-residue turbulent flow LC-MS/MS method fulfills regulatory requirements for milk antibiotic control, offering robust performance, broad analyte coverage, and operational efficiency. It represents a valuable tool for modern food safety testing.

References

• Gaugain-Juhel M., Delepine B., Gautier S., Fourmond M.P., Gaudin V., Hurtaud-Pessel D., Verdon E., Sanders P. Validation of an LC-MS/MS screening method to monitor 58 antibiotics in milk. Food Addit. Contam. 2009, 26, 1459–1471.
• Stolker A.A.M., Ruud J.B.P., Zuiderent R., DiBussolo J.M., Martins C.P.B. Fully automated screening of veterinary drugs in milk by turbulent flow chromatography and tandem mass spectrometry. Anal. Bioanal. Chem. 2010, 397, 2841–2849.
• EU Commission Decision 2002/657/EC. Official Journal of the European Communities, 2002.
• ISO 11843: Capability of Detection, 1997.