ASTM D8421-22 Standard Test Method for Determination of Per- and Polyfluoroalkyl Substances (PFAS) in Aqueous Matrices by Co-solvation Followed by Analysis Using the Shimadzu LCMS-8060NX

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants widely used in industrial and consumer products. Their stability and bioaccumulative nature pose health and ecological risks, making sensitive and reliable detection in water matrices essential for environmental monitoring and regulatory compliance.

Objectives and Overview

This study evaluates the performance of the Shimadzu LCMS-8060NX triple quadrupole liquid chromatography-tandem mass spectrometer for the determination of 44 PFAS and 24 isotopically labeled surrogate standards in non-potable water samples according to ASTM D8421-22. The method targets reporting limits of 10–400 ng/L for most analytes and aims to optimize chromatographic separation, peak shape, and calibration robustness.

Methodology and Instrumentation

Sample preparation follows a simple co-solvation extraction: 5 mL sample is spiked with surrogate mix, combined with 5 mL methanol, vortexed, acidified to pH ~4, filtered, and analyzed directly. Calibration uses commercially available mixed stock standards to generate 15-point curves within the method range. Chromatographic conditions were optimized by adjusting gradient profiles and adopting a co-injection technique (25 µL sample with 25 µL 0.1% acetic acid) to enhance early-eluting compound performance. Mass spectrometer parameters, including electrospray ionization in negative mode, interface temperature, gas flows, and collision energies, were fine-tuned for each analyte’s quantitation and confirmation ions.

Used Instrumentation

• Shimadzu LCMS-8060NX triple quadrupole LC/MS/MS
• Shim-pack Scepter C18 delay column (2.1×100 mm, 3 µm)
• Shim-pack GIST-HP C18 analytical column (3.0×100 mm, 3 µm)
• Binary gradient pump delivering mobile phase A (2 mmol/L ammonium acetate in water/acetonitrile 95/5) and B (acetonitrile)
• Column oven at 40 °C, flow rate 0.6 mL/min, interface temperature 170 °C
• Nebulizing, heating, and drying gases optimized for stable electrospray performance

Main Results and Discussion

Chromatographic optimization significantly improved peak shapes for early-eluting PFPrA and PFBA. Calibration curves exhibited excellent linearity with correlation coefficients (r²) above 0.99 for most analytes. Recovery studies in reagent water and wastewater yielded 70–130% recoveries and repeatability (RSD) below 30% across all compounds, demonstrating robust method performance.

Benefits and Practical Applications

The optimized LCMS-8060NX method exceeds ASTM D8421-22 performance criteria, offering high sensitivity, precision, and accuracy for PFAS analysis in wastewater. The use of mixed calibration standards streamlines laboratory workflows, reduces preparation time, and supports routine environmental monitoring and regulatory reporting.

Future Trends and Potential Applications

Emerging PFAS analogs and novel environmental matrices will drive further method expansion. Integration with high-resolution mass spectrometry, automation of sample preparation, and miniaturized flow systems are expected to enhance throughput and detection capabilities. Ongoing regulatory developments will necessitate continuous adaptation and validation of analytical protocols.

Conclusion

The Shimadzu LCMS-8060NX, coupled with optimized co-solvation extraction and chromatography, provides a reliable, sensitive, and efficient platform for quantifying a broad range of PFAS and surrogates in aqueous matrices, meeting stringent ASTM D8421-22 requirements.

References

1. ASTM International Test Method D8421-22 Determination of Per- and Polyfluoroalkyl Substances in Aqueous Matrices by Co-solvation followed by LC/MS/MS.
2. ASTM International Standard D8272-19 Guide for Development and Optimization of Chemical Analysis Methods Intended for EPA Compliance Reporting.
3. Lipps W., ASTM D8421-22 Standard Test Method for Determination of PFAS in Aqueous Matrices by Co-solvation and LC/MS/MS, Shimadzu Whitepaper, August 2023.