Filtration for the Analysis of Perand Polyfluoroalkyl Substances in Environmental Extracts

Significance of the Topic

Filtration plays a pivotal role in preparing environmental extracts for per- and polyfluoroalkyl substance (PFAS) analysis. By removing particulate matter and minimizing contamination or loss of analytes, appropriate filtration ensures reliable quantitation of trace-level PFAS in soils, sediments, surface water and wastewater.

Objectives and Study Overview

This application brief evaluates the performance of Agilent Captiva premium regenerated cellulose (RC) syringe filters (25 mm, 0.2 µm) for analysis of 23 PFAS compounds alongside 17 isotopically labelled surrogates. The goal was to verify background cleanliness, adsorption behavior, and recovery at low concentration levels following established EPA and ASTM protocols.

Methodology and Instrumentation

Samples were prepared according to ASTM D7968-17a, D7979-19, and draft EPA Method 8329, using acidified methanol/water (50:50, pH 3–4) as the extraction solvent. Two key experiments were conducted:

• Blank assessment: Ten milliliters of extraction solvent were passed through each filter to detect any contaminant leaching.
• Spike recovery: Extraction solvent spiked at the lower limit of quantitation (LLOQ, 5 ng/L) and midpoint concentration (80 ng/L) was filtered and analyzed.

The instrumental analysis employed liquid chromatography tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring mode.

Results and Discussion

Blank measurements across five replicates showed no PFAS above half the LLOQ (2.5 ng/L), well within acceptance criteria. Spike recovery studies at LLOQ and midpoint levels demonstrated recoveries between 50–150% and 70–130%, respectively, for all target compounds and surrogates. This confirms negligible adsorption losses and absence of filter-derived interferences, even at trace concentrations.

Benefits and Practical Applications

Use of Captiva premium RC syringe filters offers:

• Low PFAS sorption, preventing underestimation of analyte concentrations.
• Comparable or superior performance to PTFE and other materials without risk of contamination.
• Compatibility with regulatory workflows (EPA 8327/8329, ASTM D7968/7979).
• Enhanced data quality for laboratories conducting environmental PFAS monitoring.

Future Trends and Opportunities

As regulatory scrutiny and scientific interest in PFAS continue to expand, further developments may include:

• New membrane materials with even lower background and broader chemical compatibility.
• Integration with automated and high-throughput workflows.
• Advanced filter designs to handle complex matrices such as biofluids and industrial effluents.
• Expanded use of isotope dilution and high-resolution MS for comprehensive PFAS screening.

Conclusion

Agilent Captiva premium RC syringe filters deliver reliable, contamination-free performance for trace PFAS analysis in environmental extracts. Their minimal analyte sorption and robust filtration characteristics support compliance with US EPA and ASTM methods, ensuring accurate quantitation at regulatory levels.

References

1. U.S. EPA Method 8327: PFAS by LC-MS/MS, 2019.
2. ASTM D7968-17a: PFAS in Soil by LC-MS/MS, 2017.
3. ASTM D7979-19: PFAS in Water and Wastewater by LC-MS/MS, 2019.
4. Prevedouros K, Cousins IT, Buck RC, Korzeniowski SH. Environ. Sci. Technol. 2006, 40(1):32–44.
5. Lath S et al. Chemosphere 2019, 222:671–678.
6. Sörengård M et al. J. Chromatogr. A. 2020, 1609:460430.