Manual Extraction of PFAS in Drinking Water in Compliance with EPA Method 537.1

Significance of the Topic

Per and polyfluorinated alkyl substances have become ubiquitous environmental pollutants due to their extensive industrial and consumer use. Their persistence and potential health effects have prompted stringent monitoring of drinking water. Compliance with EPA Method 537.1 ensures accurate detection of trace levels of these compounds and supports regulatory decision making.

Study Objectives and Overview

This application note demonstrates a manual extraction workflow for PFAS in drinking water following EPA Method 537.1. The goals are to validate linearity, sensitivity, accuracy, precision, background levels, and potential carryover when using a Biotage VacMaster vacuum manifold with an LVE kit, ISOLUTE 101 SPE columns, and TurboVap LV evaporation, coupled to LC-MS/MS analysis.

Methodology

The procedure begins with pH adjustment of 250 mL water samples to 7 ± 0.5 using tris(hydroxymethyl)aminomethane and HCl. A surrogate standard mix is added prior to solid phase extraction on ISOLUTE 101 500 mg/6 mL cartridges. Columns are conditioned with methanol and equilibrated with water, then samples are loaded at 15 mL/min. After washing and drying, analytes are eluted with methanol. Extracts are evaporated to dryness under nitrogen at 60 °C in a TurboVap LV system, reconstituted in 96/4 methanol/water, spiked with internal standards, and analyzed by LC-MS/MS.

Instrumentation Used

• Biotage VacMaster-20 vacuum manifold with Large Volume Extraction kit
• ISOLUTE 101 SPE columns (500 mg/6 mL)
• TurboVap LV automated evaporation system with 48-position rack
• Shimadzu Nexera X2 UHPLC coupled to AB SCIEX Triple Quad 5500 with PFAS conversion kit
• Restek PFAS Delay and Raptor C18 columns
• Standard reagent water, methanol, ammonium acetate, and PFAS standard mixes

Main Results and Discussion

Calibration across nine points (0.2–100 ppt) displayed excellent linearity with forced zero intercept. Peak asymmetry factors for six early eluting PFAS remained within 0.8–1.5. Minimum reporting level was set at 2 ng/L and method detection limits were determined to be below those specified by EPA. Background studies on system blank, evaporation blank, and full reagent blank showed PFAS contributions well under one third of the MRL. An initial demonstration of precision and accuracy at 20 ng/L yielded recoveries within ±15 of nominal and relative standard deviations below 11 . Carryover experiments at high concentration (400 ng/L) revealed some residual analytes without cleaning. A dedicated VacMaster cleaning procedure reduced carryover to acceptable levels except for a single compound, indicating additional rinsing may be required for highly concentrated influent samples.

Benefits and Practical Applications

• Reliable compliance with EPA Method 537.1 requirements for drinking water analysis
• Robust SPE workflow accommodating large sample volumes and low detection limits
• Low system background and high method sensitivity
• Reproducible precision and accuracy across a broad range of PFAS
• Adaptable cleaning protocol to minimize carryover

Future Trends and Potential Applications

Ongoing developments may include further automation of sample preparation, miniaturized SPE formats, novel sorbent chemistries for emerging PFAS, high-throughput screening in environmental labs, and integration of on-site or field deployable sensors to accelerate contamination mapping.

Conclusion

The combination of Biotage VacMaster manifold, ISOLUTE 101 cartridges, TurboVap LV concentrator, and LC-MS/MS instrumentation provides a validated workflow that meets or exceeds EPA Method 537.1 criteria for PFAS analysis in drinking water. This approach ensures linearity, sensitivity, accuracy, precision, and minimal background or carryover for routine environmental testing.

References

Biotage Application Note AN958.V.2, Manual Extraction of PFAS in Drinking Water in Compliance with EPA Method 537.1, 2021