Detection and Quantitation of Per- and Polyfluoroalkyl Substances (PFAS) in Pork Meat using an LC-Orbitrap High-Resolution Mass Spectrometer

Significance of the Topic

The presence of per- and polyfluoroalkyl substances (PFAS) in food products is a growing concern due to their persistence, bioaccumulation potential, and associated health risks. Reliable detection and quantitation methods at ultra-trace levels in complex matrices such as pork meat are essential for regulatory compliance, food safety monitoring, and understanding PFAS distribution in the food chain.

Objectives and Study Overview

This study aimed to develop and validate a robust analytical workflow for simultaneous extraction, identification, and quantification of 34 target PFAS compounds in pork meat at pg/g levels. Key goals included:

• Optimizing a modified QuEChERS extraction and cleanup protocol for meat matrices.
• Implementing a solvent sandwich UHPLC injection technique to improve chromatographic performance.
• Applying full-scan data-independent acquisition (FS-DIA) on an Orbitrap Exploris 120 for high-resolution accurate-mass detection and retrospective data analysis.
• Establishing calibration, recovery, and method performance metrics in line with US FDA Method C-010.01.

Materials and Methods

Ground pork meat samples (5 g) were spiked with isotopically labeled internal standards and subjected to a modified QuEChERS extraction using acetonitrile, formic acid, and dispersive SPE salts. After cleanup, extracts were prepared for UHPLC injection using a 15 µL solvent sandwich technique (30 µL aqueous plugs bracketing the sample) to improve peak shapes. FS-DIA acquisition at 60,000 resolution (MS1) and 15,000 (MS2) enabled simultaneous quantitation and qualitative confirmation.

Used Instrumentation

• UHPLC: Thermo Scientific Vanquish Flex Binary UHPLC with PFAS analysis kit and trapping column.
• Analytical Column: Thermo Accucore C18 (100 × 2.1 mm, 2.6 µm).
• Trap Column: Thermo Hypersil Gold C18 (50 × 4.6 mm, 1.9 µm).
• Mass Spectrometer: Thermo Orbitrap Exploris 120 with ESI negative mode.
• Data Processing: Thermo TraceFinder software and myLibrary Enterprise for spectral library creation and matching.

Main Results and Discussion

The method achieved excellent linearity (r2 ≥ 0.995) across calibration ranges of 5–5000 ppt for most PFAS. Method limits of quantitation in pork meat ranged from 25 to 500 ppt. Recoveries for the majority of analytes fell within 60–130% with relative standard deviations below 10%. Notable observations included elevated blank levels for PFOA and PFBA due to reagent contamination, and lower recoveries for high-chain PFAS (PFDoA, PFTeDA), likely due to sorbent interactions. Spectral matching (fragment ion mass error <5 ppm and library scores >80) provided high confidence in compound confirmation.

Benefits and Practical Applications

• High-resolution Orbitrap detection enables sensitive quantitation and retrospective analysis for untargeted PFAS screening.
• Solvent sandwich injection enhances peak shape for early eluting, highly organic extracts.
• Modified QuEChERS extraction streamlines sample preparation for routine food monitoring.
• Validated performance metrics support method adoption in regulatory and QA/QC laboratories.

Future Trends and Applications

Expansion of high-resolution PFAS screening to other food and environmental matrices is anticipated. Advances in spectral library curation and informatics will facilitate identification of emerging PFAS. Integration with high-throughput extraction robotics and automated data processing can further improve method efficiency and data reliability.

Conclusion

The developed LC-Orbitrap method demonstrates fit-for-purpose performance for trace-level PFAS analysis in pork meat, combining streamlined QuEChERS extraction, solvent sandwich UHPLC injection, and FS-DIA acquisition. Its sensitivity, specificity, and versatility make it a valuable platform for broader PFAS surveillance in food safety and environmental studies.

References

1. Anastassiades M, Lehotay SJ, Stajnbaher D, Schenck FJ (2003) Fast and easy multiresidue method employing acetonitrile extraction/partitioning and dispersive solid-phase extraction. J AOAC Int 86:412–431.
2. US FDA Method C-010.01 (2021) Determination of 16 PFAS in Processed Food using LC-MS/MS.
3. LCGC PFAS Summit, Virtual Symposium (2022).