Improving the Longevity of PFAS Method Calibration Data with the Xevo TQ Absolute XR Mass Spectrometer

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) pose significant environmental and health risks due to their persistence and bioaccumulation. Accurate and stable calibration methods are essential for regulatory compliance and reliable analytical results. Extending calibration longevity reduces downtime, reagent costs, and operational burden in environmental testing laboratories.

Objectives and Study Overview

This study evaluated the durability of a single PFAS calibration curve over five weeks using the Xevo TQ Absolute XR Mass Spectrometer. The goal was to demonstrate extended calibration validity across diverse matrices and heavy instrument use, thereby minimizing the need for frequent recalibration runs.

Methodology and Instrumentation

Samples: river water (River Tay, Scotland), NIST 2781 biosolid, LGC 6177 landfill leachate.
Preparation: Solid-phase extraction and cleanup following established protocols for 250 mL water, 0.5 g biosolid, or 25 mL leachate.
Calibration: Linear 1/x weighted curves for 42 PFAS analytes generated on day one.
QC Monitoring: QC standards injected after every ten matrix samples over 35 days.
Instrument: Xevo TQ Absolute XR Triple Quadrupole Mass Spectrometer with waters_connect software; >7,000 matrix injections preceded calibration.

Key Results and Discussion

All calibration curves achieved relative standard error (RSE) values below 20%. Over five weeks, QC results for 42 PFAS remained within a ±30% trueness window relative to initial calibration. Most analytes exhibited relative standard deviation (RSD) under 10%, demonstrating both precision and robustness despite continuous exposure to complex matrices.

Benefits and Practical Applications

• Extended calibration lifespan up to five weeks without recalibration interruptions.
• Reduced consumption of costly PFAS standards and internal standards.
• Increased sample throughput and laboratory efficiency.
• Enhanced confidence in long-term method performance across varied environmental matrices.

Future Trends and Opportunities

Further refinement of calibration stability may include automated real-time monitoring and adaptive recalibration triggers. Integration with advanced informatics platforms could streamline data management. Expanding this approach to other analyte classes and harmonizing protocols across laboratories will support broader environmental surveillance efforts.

Conclusion

The Xevo TQ Absolute XR Mass Spectrometer maintained accurate PFAS calibration for up to five weeks under demanding conditions, reducing recalibration frequency and associated costs. This robust performance enables laboratories to focus on high-value sample analysis and supports reliable long-term environmental monitoring.

Instrumentation Used

Xevo TQ Absolute XR Triple Quadrupole Mass Spectrometer

References

• Hancock P, Adams S, Gould D. Enhanced Reliability for Long-Term PFAS Analysis with the Xevo TQ Absolute XR Mass Spectrometer, Waters Application Note, 720008824.
• Organtini KL, Rosnack KJ, Plummer C, Hancock PM, Burt O. Analysis of PFAS in Accordance with EPA 1633 Part 2: Analysis of Aqueous Matrices. Waters Application Note, 720008143.
• Organtini KL, Rosnack KJ, Plummer C, Hancock PM, Burt O. Analysis of PFAS in Accordance with EPA 1633 Part 3: Analysis of Soil and Tissue. Waters Application Note, 720008230.
• US EPA. Method 1633A for PFAS Analysis. December 5, 2024.