Screening of PFAS compounds in wastewater using adsorbable organic fluorine with combustion ion chromatography (CIC) - summary

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are widely used synthetic chemicals known for their persistence and potential health risks. Monitoring PFAS levels in wastewater is essential to protect ecosystems and human health. Adsorbable organic fluorine (AOF) measurement via combustion ion chromatography (CIC) provides a comprehensive screening approach that quantifies total organic fluorine, offering advantages over compound-specific analyses.

Objectives and Study Overview

This study evaluates the performance of CIC as described in U.S. EPA draft Method 1621 for screening PFAS in wastewater. Data from Thermo Fisher Scientific’s IC application laboratory in Sunnyvale, California, were collected as part of a multi-laboratory collaboration to assess method sensitivity, accuracy, and consistency across different PFAS compounds.

Methodology and Instrumentation

Sample Preparation:

• 100 mL of wastewater passed through two sequential granular activated carbon (GAC) columns to capture PFAS.
• Analysis focused on the eluate from the top GAC column.

CIC Analysis:

• Thermo Scientific Dionex RFIC microbore ion chromatography system combined with an offline combustion-absorption unit.
• Chromeleon CDS software for data acquisition and processing.

Key Results and Discussion

Chromatographic analysis of wastewater samples spiked with PFOS, a PFAS standard mixture, and PFBA showed recoveries between 80% and 110% for all compounds, indicating minimal compound-specific bias. Method blanks exhibited fluorine levels of 1 ng/mL, and the method detection limit (MDL) was determined to be 2.5 ng/mL. These results demonstrate the method’s high sensitivity and reliable quantitation of total organic fluorine.

Benefits and Practical Applications

• Comprehensive screening of unknown PFAS via total organic fluorine measurement.
• Effective matrix removal through combustion ensures accurate AOF quantification.
• Suitable for routine monitoring in environmental laboratories and compliance testing.

Future Trends and Potential Applications

• Adoption of automated sample preparation to improve throughput and reproducibility.
• Extension of the CIC approach to additional matrices such as soils, sediments, and food products.
• Integration with real-time monitoring platforms for on-site PFAS screening.

Conclusion

This study validates CIC under EPA draft Method 1621 as a robust, accurate, and sensitive tool for the screening of PFAS contamination in wastewater. The approach’s capacity to measure total adsorbable fluorine enhances environmental monitoring strategies and supports regulatory decision-making.

References

• Thermo Fisher Scientific Application Note AN002748.
• U.S. EPA draft Method 1621.