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

Importance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are widely recognized as persistent ‘forever chemicals’ that bioaccumulate in animal tissues, raising concerns for food safety and human health. While environmental monitoring of PFAS is well established, reliable methods for detecting ultra-trace levels in complex food matrices, such as meat, are still needed.

Study Objectives and Overview

The primary goal of this work was to establish a robust workflow capable of extracting, identifying, and quantifying 34 target PFAS compounds in pork meat at fg/g (parts-per-trillion) levels using high-resolution LC-Orbitrap mass spectrometry. The study follows guidelines from US FDA Method C-010.01 and incorporates advanced spectral library curation.

Methodology

• Sample extraction: 5 g of ground pork spiked with isotopic PFAS standards, hydrated with ultrapure water, and extracted with acidified acetonitrile using a modified QuEChERS protocol.
• Cleanup: Dispersive SPE using MgSO₄, PSA, and graphitized carbon black to remove lipids and interferences.
• Injection strategy: Solvent sandwich injection (15 µL sample bracketed by 30 µL mobile phase A plugs) to optimize peak shapes for early-eluting PFAS.
• Calibration: External and internal calibration over 5–5000 ppt; LOQs defined by recovery (60–130%) and RSD ≤ 25%.
• Spectral library creation: 34 PFAS compounds and 23 labeled analogs were individually infused and curated in myLibrary™ Enterprise to generate high-confidence MS2 libraries.

Used Instrumentation

• UHPLC: Thermo Scientific™ Vanquish™ Flex Binary system fitted with a PFAS Analysis Kit to replace Teflon surfaces.
• Columns: Thermo Scientific™ Accucore™ C18 analytical column (100 × 2.1 mm, 2.6 µm) and Hypersil Gold™ C18 trap column (50 × 4.6 mm, 1.9 µm).
• Mass spectrometer: Thermo Scientific™ Orbitrap Exploris™ 120 operated in Full Scan-Data Independent Acquisition (FS-DIA) mode with 60 000 resolution (MS1) and 15 000 resolution (MS2).
• Software: TraceFinder™ for control and quantitation; myLibrary™ Enterprise for spectral curation and library matching.

Main Results and Discussion

The method achieved limits of quantitation in pork muscle from 25 to 500 ppt, with calibration correlation coefficients (r²) ≥ 0.995 and intra-day RSDs < 10% for most analytes. Fragment ion matches at < 5 ppm mass accuracy and library scores > 80 confirmed compound identities. Recoveries generally ranged between 60% and 130%, although PFDoA and PFTeDA showed lower recoveries and higher variability, likely due to sorbent interactions. Blank controls revealed low-level PFOA and PFBA contamination from dSPE reagents.

Benefits and Practical Applications

• High analytical sensitivity enables detection of PFAS at fg/g levels without additional concentration steps.
• Full-scan HRAM data support retrospective screening for emerging PFAS in food and environmental samples.
• The approach aligns with regulatory guidelines (US FDA C-010.01) and can serve routine QA/QC in food safety laboratories.
• Solvent sandwich injection ensures robust chromatography for a broad range of PFAS chemistries.

Future Trends and Opportunities

Advances in HRAM instrumentation and spectral library curation are expected to expand the number of target and non-target PFAS analytes. Development of certified reference materials for complex matrices and automation of QuEChERS workflows will further streamline high-throughput PFAS testing. Integration with multi-residue screening platforms could provide comprehensive monitoring of chemical contaminants in food.

Conclusion

This LC-Orbitrap method demonstrates excellent quantitative performance and confident qualitative confirmation for 34 PFAS in pork meat at ultra-trace levels. The combined use of modified QuEChERS extraction, solvent sandwich injection, and curated HRAM spectral libraries provides a fit-for-purpose platform adaptable to other challenging matrices.

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 for pesticide residues in produce. J AOAC Int 86:412–431.
2. US FDA Method C-010.01 Determination of 16 Per- and Polyfluoroalkyl Substances (PFAS) in Processed Food using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). 2021.
3. LCGC PFAS Summit: A Virtual Symposium, 2022.