Evaluation of the Performance of a Total Workflow Approach for the Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Fish, Using an Interlaboratory Study

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent pollutants that accumulate in aquatic food chains. Monitoring PFAS in fish is crucial to assess dietary exposure, support regulatory compliance, and inform risk assessments.

Objectives and Study Overview

This interlaboratory study assessed the performance of a comprehensive PFAS workflow for fish analysis. Seven laboratories received a quality control material spiked with PFHxS, PFOS, PFOA, and PFNA, along with method protocols, standards, and blanks, to evaluate method trueness, repeatability, and reproducibility.

Methodology and Instrumentation

The method combined alkaline methanol extraction and selective cleanup using Oasis WAX SPE cartridges, followed by UPLC–MS/MS analysis. Key instrumentation:

• ACQUITY UPLC I-Class PLUS System with BEH C18 Column
• PFAS Analysis Kit and Isolator Column
• Xevo TQ-XS Tandem Quadrupole Mass Spectrometer

Calibration employed solvent standards bracketing sample extracts, with linear or quadratic fits achieving r2 > 0.99 and residuals within ±20%.

Main Results and Discussion

All laboratories achieved stable retention, Gaussian peaks, and detection limits matching prior performance. Trueness ranged from 102% to 121% for the four target PFAS. Within-laboratory repeatability (RSDr) was below 20%, and between-laboratory reproducibility (RSDRL) was ≤ 30%. No PFAS were detected in blank samples.

Benefits and Practical Applications

• A single workflow delivers accurate PFAS quantification in fish at sub-µg/kg levels.
• Method meets EU regulatory limits and supports compliance monitoring.
• Sensitivity and robustness enable reliable data for risk assessments.

Future Trends and Opportunities

Advances may include expanded PFAS panels, automation of sample preparation, and integration with high-resolution mass spectrometry. Ongoing harmonization of protocols will facilitate global data comparability and regulatory standardization.

Conclusion

The interlaboratory study confirms that the proposed method delivers accurate, repeatable, and reproducible PFAS measurements in fish tissue. It is well suited for routine compliance testing and environmental monitoring.

Reference

• Schrenk D et al. EFSA CONTAM Panel, EFSA J 2020;18(9).
• Commission Recommendation (EU) 2022/1431.
• Commission Regulation (EU) 2022/1428.
• EURL-POPs Guidance Document v1.2 (2022).
• Organtini K et al. Waters Application Note 720007482, 2022.