Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Food Samples with LC-MS/MS

Importance of the topic

Per- and polyfluoroalkyl substances (PFAS) are highly stable fluorinated compounds widely used as water repellents, coating agents and firefighting foams. Their persistence and bioaccumulation raise concerns about dietary exposure through contaminated food. Developing a reliable analytical workflow for PFAS in food matrices is critical to support food safety monitoring and regulatory compliance.

Objectives and study overview

This study aimed to establish a rapid, sensitive LC-MS/MS method for quantifying forty PFAS in food samples. Researchers focused on optimizing a simple QuEChERS-based extraction and solid-phase extraction (SPE) cleanup using two cartridge chemistries, then validating recoveries under low concentration conditions.

Methodology and instrumentation

Sample preparation began with 10 g of homogenized carrot extracted with acetonitrile and QuEChERS salts, followed by a single centrifugation. The supernatant was diluted and subjected to SPE using either a weak anion exchange cartridge (InertSep MA-2) or a mixed-mode WAX cartridge. Twelve elution fractions were tested at methanol ratios from 0 to 100 % under neutral, acidic and alkaline conditions. Final cleanup employed formic acid/methanol/water and ammonia/methanol/water mixtures selected to maximize recovery and minimize losses. Concentration by nitrogen blow-down was evaluated but abandoned due to significant losses of certain PFAS.

Used instrumentation

• Shimadzu Nexera X3 UHPLC system
• Shimadzu LCMS-8050 triple quadrupole mass spectrometer (ESI, negative mode)
• Shim-pack Scepter™ C18-120 column (100 mm × 2.0 mm I.D., 1.9 µm)
• Shim-pack GIST C18 delay column (50 mm × 3.0 mm I.D., 5 µm)

Main results and discussion

Optimal SPE conditions employed a 1:400:600 (v/v/v) formic acid/methanol/water wash and 1:90:10 (v/v/v) ammonia/methanol/water elution. Both cartridges achieved 70–120 % recoveries for all forty PFAS without significant differences. Chromatographic separation of PFAS was completed in 15 minutes, with clear detection of target analytes and minimal matrix interference.

Benefits and practical applications

This workflow offers a fast, reproducible approach for routine PFAS monitoring in food laboratories. The minimal sample handling reduces contamination risk, while use of low-binding polypropylene vials further lowers background. The method supports compliance testing, exposure assessment and research on PFAS occurrence in diverse food matrices.

Future trends and potential applications

Emerging opportunities include expanding analyte panels to cover novel PFAS, integrating automated SPE systems for higher throughput, and employing high-resolution mass spectrometry for non-target screening. Miniaturized extraction techniques could enable analysis of limited sample volumes and complex matrices.

Conclusion

The developed LC-MS/MS method reliably quantifies forty PFAS in food samples with high throughput, reproducible recoveries and simplified sample preparation. It is well suited for routine food safety laboratories addressing PFAS contamination concerns.

References

Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS, 2nd draft Method 1633, EPA (June 2022).