Analysis of Per- and Polyfluoroalkyl Substances (PFAS) using Triple Quadrupole Mass Spectrometer Part 1 - Fish Fillet

Importance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent organofluorine compounds used in applications such as firefighting foams, food packaging, and non-stick coatings. Their chemical stability leads to environmental persistence and bioaccumulation in aquatic organisms. Human exposure through fish consumption raises health concerns, making accurate PFAS quantification in seafood essential for risk assessment and regulatory compliance.

Objectives and Study Overview

This work presents a validated analytical procedure for simultaneous quantification of thirty PFAS in tuna fillet. The method follows AOAC INTERNATIONAL SMPR criteria, aiming to achieve limits of quantification at or below 0.1 µg/kg for major PFAS and robust performance across all targets.

Methodology

The protocol integrates QuEChERS extraction, solid-phase cleanup, and triple quadrupole LC-MS/MS detection:

• Sample Preparation
  • Pulverize frozen tuna fillet with dry ice
  • Extract 10 g sample with 10 mL acetonitrile and QuEChERS salt
  • Centrifuge, collect acetonitrile layer, dilute five-fold with water
• SPE Cleanup
  • Condition EVOLUTE PFAS cartridge with ammonium hydroxide/methanol and formic acid/methanol
  • Load 40 mL extract, wash with water and formic acid/methanol/water
  • Elute PFAS with ammonium hydroxide/methanol/water, acidify eluate before analysis

Used Instrumentation

• Shimadzu LCMS-8060NX triple quadrupole mass spectrometer with ESI negative mode
• Nexera X3 UHPLC system
• Shim-pack Scepter C18 analytical column (100 × 2.1 mm, 3 µm) and delay column (50 × 2.1 mm, 3 µm)
• Biotage EVOLUTE PFAS SPE cartridges (150 mg/6 mL)

Main Results and Discussion

Chromatographic separation achieved baseline resolution of all PFAS within 8 minutes, including effective separation of interfering bile acids. Matrix-matched calibration from 0.05 to 5 µg/kg yielded strong linearity (R² > 0.99). Limits of quantification were ≤ 0.1 µg/kg for PFOS, PFOA, PFNA, and PFHxS, and ≤ 1.0 µg/kg for other targets. Recovery tests at 0.1, 1, and 5 µg/kg showed recoveries of 81.6–114.1% and repeatability (RSD) below 17.1%, satisfying AOAC SMPR requirements.

Benefits and Practical Applications

The optimized method allows sensitive and accurate PFAS monitoring in fish matrices at regulatory thresholds. Its streamlined workflow supports high-throughput testing in food safety laboratories, environmental monitoring, and quality control routines.

Future Trends and Opportunities

Emerging advancements may include automation of sample preparation, use of high-resolution mass spectrometry for non-target PFAS screening, and adaptation to diverse food and environmental samples. Integration with informatics tools and laboratory information management systems (LIMS) can further enhance data handling and regulatory reporting.

Conclusion

A robust LC-MS/MS method using Shimadzu LCMS-8060NX and Nexera X3 UHPLC with optimized pretreatment provides reliable quantitation of thirty PFAS in tuna fillet at sub-µg/kg levels. The approach meets AOAC SMPR criteria and offers a strong foundation for routine food safety analysis and future methodological expansions.

References

• AOAC SMPR 2023.003