A Comprehensive Workflow for the Analysis of PFAS in Wastewater per EPA Method 1633

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent pollutants with widespread environmental and health impacts due to their chemical stability and bioaccumulation potential. Accurate ultratrace analysis in complex wastewater matrices is vital for monitoring contamination and supporting regulatory compliance.

Objectives and Study Overview

This study presents a comprehensive workflow compliant with EPA Method 1633 Draft 4 for the quantitation of over 57 PFAS in wastewater samples. Key aims include evaluating method detection limits, recovery, precision, linearity, and long-term robustness, as well as implementing automated sample tracking and report generation.

Methodology and Instrumentation

• Sample Preparation: 500 mL wastewater spiked with extracted internal standards concentrated by Agilent Bond Elut PFAS WAX weak anion exchange SPE, eluate acidified, cleaned with Agilent Carbon S, filtered, and spiked with nonextracted internal standards.
• Chromatography: Agilent 1290 Infinity II LC system equipped with a PFC-free conversion kit and delay column; ZORBAX RRHD Eclipse Plus C18 columns.
• Mass Spectrometry: Agilent 6495D triple quadrupole LC/MS with optimized multiple reaction monitoring transitions from Agilent PFAS MRM database.
• Software: Agilent SLIMS for sample management and MassHunter Quantitative Analysis for data processing and automated PDF reporting.

Main Results and Discussion

• Calibration: Seven-point calibration curves for 40 native PFAS achieved RSE below 10% over concentration ranges corresponding to ppt–ppq levels.
• Method Detection Limits: MDLs met or were lower than EPA 1633 pooled values, demonstrating ng/L sensitivity.
• Recovery and Accuracy: Mean recoveries near 100% in reagent water and wastewater with RSD below 5%.
• Robustness: Analysis of 300 continuous injections showed RSD below 6% for 19 representative PFAS, confirming stable performance over extended runs.
• Automated Reporting: Custom report templates calculate ion ratios, EIS recoveries, integration checks, and concentrations in compliance with EPA requirements.

Benefits and Practical Applications

The workflow delivers high-throughput, reliable PFAS monitoring for environmental laboratories, facilitating regulatory compliance and quality control. Automated sample tracking and reporting streamline operations and reduce manual errors.

Future Trends and Opportunities

• Integration of high-resolution mass spectrometry and non-targeted screening for emerging PFAS and transformation products.
• Further automation with robotic SPE and online sample preparation to enhance throughput.
• AI-driven data analysis and advanced software for pattern recognition in complex contaminant profiles.
• Harmonization of global PFAS analytical standards to support evolving regulations.

Conclusion

The Agilent workflow according to EPA Method 1633 Draft 4 provides a robust, sensitive, and fully automated solution for PFAS analysis in wastewater. It achieves low detection limits, excellent recoveries, stable long-term performance, and seamless reporting, supporting environmental monitoring and compliance initiatives.

References

• EPA. Our Current Understanding of the Human Health and Environmental Risks of PFAS. Last updated 2023.
• EPA Method 1633 Draft 4: Analysis of PFAS in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS. U.S. EPA, July 2023.
• Hunt K; Hindle R; Anumol T; Giardina M; Parry E. Analysis of PFAS in Aqueous Samples per EPA Draft Method 1633. Agilent Technologies, 2022.
• EPA. Definition and Procedure for the Determination of the Method Detection Limit—Revision 2. 40 CFR Part 136, Appendix B.