Refining PFAS Methods to Improve the Reliability of Reported DataEnsuring Reliable Data
Oral Presentation
Prepared by L. Cook1, D. Truini2
1 - Weston & Sampson, 55 Walkers Brook Drive, Suite 100, Reading, MA, 01867, United States
2 - Exponent, 1075 Worcester Street, Natick, MA, 01760, United States
Contact Information: [email protected]; 781-640-8396
ABSTRACT
Isotope dilution analysis (IDA) is a highly specialized and robust technique for quantifying per- and polyfluoroalkyl substances (PFAS) in environmental matrices. This method requires sophisticated instrumentation, isotopically labeled standards, precise mass spectrometric analysis, and a team of experienced analysts skilled in both analytical method execution and data interpretation. Recently, the U.S. Environmental Protection Agency (EPA) finalized Method 1633 for use within the regulated community, marking significant progress toward the standardization of PFAS analysis. However, critical reviews of data generated using this method have identified areas where refinements are needed to improve the accuracy, precision, and overall reliability of reported PFAS data.
In this presentation, we will discuss three key areas in Method 1633 that require further refinement. First, detection and reporting limits should be adjusted based on the extraction efficiency of the associated extracted internal standards (EIS), ensuring that reported limits of detection and quantification more accurately reflect real-world sample variability. Second, a more prescriptive approach is needed for handling positive detections of compounds when ion ratio exceedances occur, reducing inconsistencies in data interpretation and minimizing the risk of reporting false positive detections. Third, the adoption of standard reference materials as a benchmark would provide a much-needed quality control measure, allowing for better assessment of method variability both within and between laboratories. Incorporating these refinements into PFAS analyses will enhance data consistency, increase confidence in PFAS measurements, and strengthen the scientific integrity of results used for regulatory compliance and environmental decision-making.
