Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Fish Fillet with LC-MS/MS

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants with widespread use in industrial and consumer products. Their stability and bioaccumulation raise concerns about human exposure through diet, particularly via contaminated fish. Reliable, rapid analytical methods are essential to monitor and manage PFAS levels in food.

Goals and Study Overview

This study aims to develop and validate a quantitative LC-MS/MS method for thirty PFAS compounds in fish fillet. Key objectives include optimizing sample preparation, achieving complete chromatographic separation within 15 minutes, and meeting stringent recovery, repeatability, and limit of quantification criteria defined by regulatory standards.

Methodology and Instrumentation

The workflow comprises three main steps:

• Extraction by QuEChERS: Ten grams of frozen-ground fish are mixed with acetonitrile and QuEChERS salt, hand-shaken, then centrifuged. The acetonitrile extract is diluted fivefold.
• Purification by SPE: EVOLUTE PFAS cartridges are conditioned with ammonium hydroxide/methanol and formic acid/methanol. Forty milliliters of extract are loaded, washed, and eluted. The eluate is acidified and prepared for analysis.
• LC-MS/MS Analysis: A Nexera X3 UHPLC system coupled to LCMS-8060NX is used. Separation employs a Shim-pack Scepter C18 column with a gradient of acetonitrile and water containing ammonium acetate. Flow switching ensures wash steps. Negative-mode ESI, optimized gas flows and temperatures, and a 5 µL injection volume enable detection.

Main Results and Discussion

All thirty PFAS eluted within eight minutes, demonstrating efficient separation from bile acids. Calibration curves in the 0.05–5 µg/kg range showed high linearity (R2 ≥ 0.98). Limits of quantification for PFOS, PFOA, PFNA, and PFHxS met stringent criteria (0.1 µg/kg, recovery 80 – 120%, repeatability < 20%). Other PFAS achieved LOQs of 1.0 µg/kg with acceptable recoveries (65 – 135%) and repeatability (< 25%).

Benefits and Practical Applications

This rapid, robust method supports routine monitoring of PFAS in fish for food safety and regulatory compliance. The streamlined QuEChERS-SPE workflow and fast LC-MS/MS analysis enhance laboratory throughput and reduce solvent consumption, making it suitable for industrial, government, and research settings.

Future Trends and Potential Applications

Emerging trends include miniaturized sample preparation, high-throughput automated platforms, and expanding the method to additional matrices such as shellfish and water. Integration with high-resolution mass spectrometry and data analytics can further improve selectivity, sensitivity, and large-scale environmental surveillance.

Conclusion

The developed LC-MS/MS protocol enables reliable quantification of thirty PFAS compounds in fish fillet within fifteen minutes. It meets regulatory performance standards and offers a practical tool for routine food safety monitoring and environmental research.

Reference

1) AOAC SMPR®2023.003