Comparison of Dual Sorbent Solid Phase Extraction for PFAS Applications

Importance of the Topic

Environmental contamination by PFAS poses significant risks due to their persistence and bioaccumulation. Reliable and efficient analytical methods are essential to monitor these compounds at trace levels in water and other matrices. Dual-phase solid phase extraction combining weak anion exchange and graphitized carbon sorbents offers a streamlined approach compatible with automation and regulatory requirements such as US EPA Method 1633.

Objectives and Study Overview

This study aims to evaluate the performance of Agilent Bond Elut PFAS WAX/Carbon S dual-phase SPE cartridges against two commercial benchmarks under US EPA Method 1633 guidelines. Key goals include assessing extraction recoveries for 40 target PFAS compounds and the corresponding isotope-labeled extracted internal standards at low concentration levels in reagent water.

Methodology

• Sample Preparation: 250 mL of reagent water spiked with 4 ng/L of 40 PFAS targets.
• SPE Procedure: Automated extraction using 6 mL cartridges packed with 200 mg PFAS WAX on top and 50 mg Carbon S at the bottom; four replicate extractions per cartridge type (two for one benchmark).
• Quantification: Recoveries determined by LC-MS/MS quantification against 24 isotope-labeled internal standards.

Used Instrumentation

• Automated solid phase extraction system.
• 6 mL Agilent Bond Elut PFAS WAX/Carbon S SPE cartridges with low-background frits.
• LC-MS/MS system for PFAS analysis.

Main Results and Discussion

The dual-phase Agilent cartridges achieved average target recoveries within the acceptance limits defined by EPA Method 1633 and demonstrated consistent EIS recoveries. Performance was comparable to, and in some cases exceeded, that of benchmark WAX/GCB cartridges. The layered sorbent design effectively isolated a broad range of PFAS while reducing matrix interferences, confirming suitability for routine, automated laboratory workflows.

Benefits and Practical Applications

• Streamlined sample processing by combining two sorbents into a single cartridge.
• Compatibility with automation platforms enhances throughput and reproducibility.
• Lot-tested sorbents ensure low background PFAS levels and high analyte recovery.
• Direct integration into existing EPA Method 1633 protocols without modification.

Future Trends and Opportunities

As PFAS analysis evolves, future developments may include cartridge miniaturization for reduced solvent and sample volumes, expanded sorbent chemistries to target emerging PFAS, and integration with high-resolution mass spectrometry for enhanced specificity. On-line SPE-LC-MS/MS workflows and field-deployable systems are poised to improve environmental monitoring efficiency.

Conclusion

Agilent Bond Elut PFAS WAX/Carbon S dual-phase SPE cartridges deliver robust, automated sample preparation for PFAS analysis compliant with US EPA Method 1633. Their performance aligns with benchmark products while offering streamlined workflows and low PFAS background, supporting reliable environmental monitoring.

References

• EPA Method 1633A: Analysis of Per- and Polyfluoroalkyl Substances in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS; U.S. EPA, Office of Water, Engineering and Analysis Division, 2024.
• Giardina M. Determination of Per- and Polyfluoroalkyl Substances in Drinking Water Using Agilent Bond Elut PFAS WAX SPE and LC/MS/MS. Agilent Technologies, application note 5994-4960EN, 2024.
• Giardina M. Determination of Per and Polyfluoroalkyl Substances in Soils Using Carbon S SPE by LC/MS/MS. Agilent Technologies, application note 5994-4770EN, 2022.
• Novello A., Mihelich B., Giardina M. Automated Solid Phase Extraction of PFAS from Aqueous Samples: Using Dual-phase Agilent Bond Elut PFAS WAX/Carbon S SPE Cartridges for US EPA Method 1633. Agilent Technologies, application note 5994-8289EN, 2025.