Automating the Sample Preparation Workflow for Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous Samples Following EPA Method 1633

Importance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants of growing concern in water resources. Reliable analysis of PFAS in aqueous matrices is essential for regulatory compliance, public health protection and environmental monitoring. Automating complex sample preparation workflows can enhance laboratory throughput, reduce turnaround times and minimize operator variability.

Objectives and Study Overview

This study adapts US EPA Method 1633 for PFAS in water samples to a fully automated solid-phase extraction (SPE) process using the Promochrom SPE-03 system. The goals were to halve sample preparation time, maintain compliance with EPA quality control criteria and demonstrate equivalence to manual SPE methods across diverse water matrices.

Used Instrumentation

• Promochrom SPE-03 Gen 4 Automated SPE System
• Oasis WAX/GCB bilayer dual-phase SPE cartridges
• Waters ACQUITY Premier BSM FTN UPLC System
• Waters Xevo TQ Absolute Mass Spectrometer
• waters_connect™ software for data processing

Methodology

Authentic samples—groundwater, surface water, influent and effluent wastewater—were collected in 250 mL polypropylene bottles, spiked with isotope-labeled internal standards, frozen and thawed per EPA 1633 guidelines. Automated SPE utilized inline filters, anti-clogging tips and glass wool for high-particulate wastewater. Extraction steps mirrored EPA 1633 solvent and cartridge conditioning protocols. Final extracts were analyzed by LC-MS/MS with a C18 analytical column, ammonium acetate mobile phases and negative electrospray ionization.

Main Results and Discussion

• Method blanks showed no PFAS contributions from the SPE system; background PFBA arose from reagents.
• Extracted internal standard recoveries averaged 78.2% ± 8.1% across sample types, exceeding EPA minimum criteria.
• Certified reference material quantification achieved 103% mean trueness (range 81.8–120%) and 2.9% mean RSD, matching or surpassing manual workflows.
• Ongoing precision and recovery (OPR) samples and calibration verification injections remained within ±30% deviation over multiple batches.
• Authentic water analyses revealed PFAS detection patterns and concentrations comparable to manual preparation results.

Benefits and Practical Applications

• Sample preparation time reduced from 3–4 hours to approximately 2 hours per batch.
• Higher throughput and consistent compliance with EPA 1633 QC guidelines.
• Decreased operator workload and enhanced reproducibility across water matrices.

Future Trends and Possibilities

Integration of automated SPE with high-resolution mass spectrometry and data analytics platforms could enable comprehensive PFAS screening in complex environmental samples. Further miniaturization of cartridges and development of next-generation sorbents may improve sensitivity and reduce solvent consumption. Adoption of cloud-based QC tracking and remote monitoring will support method standardization across laboratories.

Conclusion

The automated SPE workflow for PFAS analysis following EPA Method 1633 has been validated as equivalent to manual procedures. It delivers reliable recoveries, low contamination risk and accelerated sample processing. Laboratories can implement this approach to enhance capacity, maintain regulatory compliance and support environmental PFAS monitoring programs.

References

1. US Environmental Protection Agency Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous, Solid, Biosolids, and Tissue Samples by LC-MS/MS, Draft 4, July 2023.
2. K. Organtini, K. Rosnack, C. Plummer, P. Hancock, O. Burt Analysis of Per- and Polyfluoroalkyl Substances (PFAS) in Accordance with EPA 1633 Part 2: Analysis of Aqueous Matrices Waters Application Note 720008143, December 2023.