From Coop to Carton: A Study of PFAS in Backyard & Store-Bought Eggs Using Automation and LC-MS/MS

Significance of the Topic

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants of growing concern. Eggs from backyard chickens may accumulate PFAS through soil, water, feed, and bedding, raising potential food safety issues. A reliable, high-throughput method to monitor PFAS in eggs supports public health and regulatory compliance.

Objectives and Study Overview

This study aims to compare PFAS levels in store-bought cage-free eggs and backyard free-range eggs. It also introduces an automated sample preparation workflow coupled with LC-MS/MS to enhance consistency and throughput when analyzing whole egg matrices.

Methodology and Instrumentation

The workflow employs automated alkaline extraction followed by dual-phase solid-phase extraction using Oasis GCB/WAX cartridges. Extracts are analyzed by UPLC–MS/MS under electrospray ionization. Key steps include:

• Alkaline digestion in a CEM EDGE system
• Cleanup on Promochrom SPE-03 with Oasis GCB/WAX cartridges
• Concentration under nitrogen and reconstitution in aqueous solvent

Instrumentation Used

• CEM EDGE PFAS extraction system
• Waters Promochrom SPE-03 with Oasis GCB/WAX cartridges
• Waters ACQUITY Premier UPLC system with BEH C18 AX column
• Waters Xevo TQ Absolute mass spectrometer
• waters_connect software for quantitation

Main Results and Discussion

Out of 45 PFAS compounds monitored, 24 were detected in at least one sample. Backyard eggs generally exhibited higher PFAS concentrations and greater compound diversity compared to store-bought eggs. Notably, legacy precursors such as FOSA and FTCA appeared only in grocery eggs. Recovery experiments showed most PFAS achieved 70–130% recovery, including regulated compounds (PFOS, PFOA, PFNA, PFHxS), confirming method robustness despite the complex egg matrix.

Benefits and Practical Applications

The automated approach reduces analyst workload, improves reproducibility, and processes up to eight samples in under 70 minutes. Its broad applicability to regulated and emerging PFAS makes it suitable for food safety laboratories monitoring PFAS in challenging matrices.

Future Trends and Potential Applications

As regulatory limits evolve and new PFAS emerge, this flexible workflow can adapt to expanding target lists. Integration with high-resolution MS and environmental tracing could further elucidate PFAS sources in food chains. Routine application in quality control and environmental studies will enhance consumer safety and regulatory enforcement.

Conclusion

The developed automated SPE–LC-MS/MS method delivers fast, reproducible quantitation of PFAS in whole eggs. It differentiates contamination profiles between backyard and commercial eggs, supporting informed risk assessment. The robust workflow future-proofs laboratories for ongoing PFAS monitoring.

References

• Official Journal of the European Union. Regulation of PFAS levels in eggs (8.12.2022).
• U.S. Food and Drug Administration. Analytical Results of Testing Food for PFAS from Environmental Contamination.