Analysis of PFAS Specified in EPA Method 537 and Beyond using Shimadzu UFMS™

Importance of the Topic

Per- and polyfluorinated alkyl substances (PFAS) are persistent pollutants widely found in industrial, firefighting and consumer applications. Their resistance to degradation and potential health risks in drinking water make sensitive and reliable analysis essential for environmental monitoring and regulatory compliance.

Objectives and Study Overview

This study evaluates the performance of Shimadzu’s Ultra-fast Mass Spectrometry (UFMS™) platforms—LCMS-8045 and LCMS-8050—for analyzing 21 PFAS defined in EPA Method 537 plus seven additional fluorotelomer precursors. Key goals:

• Extend EPA 537 scope to 27 PFAS compounds.
• Demonstrate method sensitivity, accuracy and precision in drinking water matrices.
• Compare instrument detection limits and calibration linearity.

Methodology and Used Instrumentation

Sample Preparation:

• 250 mL water samples fortified with internal standards and surrogates.
• Solid phase extraction (SPE) using Biotage-ISOLUTE® SDVB cartridges following EPA 537 protocol.
• Elution with methanol, nitrogen evaporation, reconstitution in 96:4 methanol:water.

Chromatography and Detection:

• UHPLC separation on Shim-pack™ Velox SP-C18 column.
• Mobile phase: 20 mM ammonium acetate (A) and methanol (B), 0.25 mL/min, 35 min run.
• Electrospray ionization triple quadrupole MS with fast polarity switching and 555 MRM/sec acquisition.
• Instrument models: Shimadzu Nexera™ X2 with LCMS-8045 and LCMS-8050.

Main Results and Discussion

Calibration and Linearity:

• Ten-point calibration (1.25–100 ng/mL) achieved R2 > 0.99 for all PFAS on both instruments.
• Continuing calibration checks at low, mid and high levels met EPA criteria (70–130% recovery, ≤ 15% RSD).

Method Detection Limits (MDL):

• LCMS-8045: 0.7–3.3 ng/L;
• LCMS-8050: 0.7–1.7 ng/L.

Accuracy and Precision:

• Seven replicates spiked at 60 ng/L showed recoveries within 80–110% and RSD ≤ 20% on both systems.
• Surrogate recoveries (M2PFHxA, M2PFDA, M-EtFOSAA) were 100–110% with ≤ 15% RSD.

Chromatographic Performance:

• Effective separation of linear and branched PFHxS and PFOS isomers.
• Solvent delay column minimized background PFAS interference from mobile phases.

Benefits and Practical Applications

• High sensitivity at low ppt levels supports regulatory compliance for drinking water standards.
• Reduced injection volume (1 µL vs. 10 µL) enhances robustness and lowers maintenance costs.
• Fast polarity switching and high acquisition rates enable multi-method workloads on a single platform.

Future Trends and Opportunities

• Expansion of compound panels to emerging PFAS and metabolites.
• Integration with automated on-line SPE or microflow LC to further reduce sample prep and resource consumption.
• Adoption of high-resolution MS for non-target suspect screening alongside targeted methods.

Conclusion

Shimadzu UFMS™ systems, especially the LCMS-8050, deliver reliable, high-throughput PFAS quantitation in drinking water, meeting or exceeding EPA Method 537 requirements. Their speed, sensitivity and low sample injection demands make them well suited for modern environmental laboratories facing expanding PFAS monitoring challenges.

References

1. U.S. EPA Method 537 Determination of Selected Perfluorinated Alkyl Acids in Drinking Water by SPE and LC-MS/MS, 2009.
2. ASTM D7979-17 Standard Test Method for Determination of Perfluorinated Compounds in Water by LC-MS/MS, 2017.