Determination of PFAS in Fish Oil, Offal and Coffee by LC-MS/MS

Importance of the Topic

Poly- and perfluoroalkyl substances (PFAS) are persistent environmental contaminants associated with adverse health effects. Monitoring PFAS in foodstuffs such as fish oil, edible offal, and coffee is critical to safeguard consumer health and ensure compliance with regulatory limits.

Objectives and Study Overview

This study aimed to develop and validate a rapid, single‐laboratory LC-MS/MS method for simultaneous quantification of 30 PFAS at low ng/g levels in fish oil, offal, and coffee. Key goals included meeting AOAC SMPR 2023.003 acceptance criteria, with emphasis on stricter EU LOQ requirements for PFOA, PFNA, PFOS, and PFHxS in offal.

Methodology

• Sample Preparation: Beef kidney was sliced, frozen with dry ice, and ground; coffee was sampled directly; fish oil was released from gel capsules.
• Spiking: Test portions (10 g) were fortified in triplicate with 30 native PFAS and 16 isotopically labeled internal standards.
• Extraction: Acetonitrile addition, vortex, centrifugation, followed by 5× dilution with PFAS-free water and cleanup via weak anion exchange SPE eluted with basic methanol–water.
• Quantification: Isotope dilution LC-MS/MS using a Shimadzu Nexera liquid chromatograph coupled to an LCMS-8060NX triple quadrupole operated in negative electrospray mode.
• Chromatography: Optimized gradient achieved baseline separation of PFAS isomers and resolved potential cholic acid interferences within a nine-minute runtime.

Used Instrumentation

• Shimadzu Nexera liquid chromatograph
• Shimadzu LCMS-8060NX triple quadrupole mass spectrometer with heated electrospray ionization

Main Results and Discussion

• Calibration: Linear calibration models with residuals within ±25% across all concentration levels.
• Recovery and Precision: Recoveries between 93% and 117% and repeatability (RSD) below 7% for PFOA, PFNA, PFOS, and PFHxS; similar performance observed for remaining PFAS.
• Limits of Quantitation: Achieved or exceeded SMPR 2023.003 LOQ requirements for all 30 PFAS; EU-regulated compounds in offal met stricter LOQs.
• Chromatographic Separation: Clear resolution of branched/linear isomers and effective separation from matrix interferences.

Benefits and Practical Applications

• Unified method applicable to diverse food matrices, reducing method development time.
• Fast analysis (<9 min per run) enhances laboratory throughput.
• Compliance with both AOAC and EU regulatory standards for PFAS in food.
• Suitable for food safety monitoring, quality control, and environmental exposure studies.

Future Trends and Opportunities

• Expansion to additional food and environmental matrices, including emerging PFAS.
• Coupling with high-resolution mass spectrometry for non‐targeted screening.
• Implementation of automated sample preparation workflows for higher throughput.
• Integration into large‐scale surveillance programs and risk assessment frameworks.

Conclusion

The validated LC-MS/MS method delivers reliable, rapid, and regulatory-compliant measurement of 30 PFAS in fish oil, offal, and coffee, supporting robust food safety and quality assurance efforts.

Reference

No external literature references were provided in the source document.