Analysis of Per-and Polyfluoroalkyl Substances (PFAS) using the LCMS-8050 Triple Quadrupole Mass Spectrometer According to EPA Draft Method 1633

Importance of the Topic

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental pollutants with potential adverse health effects. Sensitive and reliable analytical methods are critical for monitoring these compounds in water and wastewater to support regulatory compliance and protect public health.

Objectives and Study Overview

This study assesses the Shimadzu LCMS-8050 triple quadrupole mass spectrometer for quantifying 40 target PFAS according to U.S. EPA draft Method 1633. The evaluation covers performance criteria in reagent water and complex wastewater matrices, focusing on limits of quantitation, linearity, accuracy, precision, and recovery.

Methodology and Sample Preparation

The workflow follows EPA draft 1633 guidelines:

• Calibration standards prepared at 0.2–250 ng/mL for targets, 1.25–25 ng/mL for extracted internal standards (EIS), and 1.25–5 ng/mL for non-extracted internal standards (NIS).
• Extraction by solid phase extraction (SPE) with pre-conditioned cartridges, sample loading at 5 mL/min, drying, and elution with methanolic ammonium.
• Post-extraction addition of NIS to each extract.

Instrumentation Used

• Shimadzu Nexera UHPLC system.
• Shimadzu LCMS-8050 triple quadrupole mass spectrometer.
• Analytical column: Shim-pack GIST-HP C18 (2.1 × 50 mm, 3 µm) and delay column: Shim-pack GIST C18 (3.0 × 50 mm, 5 µm).
• Mobile phases: A – 2 mM ammonium acetate in 5% acetonitrile; B – acetonitrile; gradient at 0.4 mL/min over 20 min; injection volume 2 µL; column oven at 40 °C.
• MRM acquisition with 72 transitions optimized for precursor/product ions and collision energies.

Main Results and Discussion

Calibration curves demonstrated linearity (relative standard error ≤20%). Limits of quantitation met or exceeded EPA draft 1633 requirements, with signal-to-noise ratios at the lowest standard ranging from 8 to >30 000. Instrument detection limits (IDLs) ranged from 0.01 to 1.9 ng/mL. Accuracy at the lowest calibration level was 80–116%, and repeatability (%RSD) was below 20% for the majority of analytes across low, mid, and high concentration standards. Extracted internal standard recoveries in both ultrapure water and wastewater were within acceptable ranges (50–150%), confirming robustness in complex environmental samples.

Benefits and Practical Applications of the Method

The optimized LCMS-8050 workflow offers:

• Achievement of stringent LOQs in line with EPA draft 1633.
• Robust performance in high-matrix wastewater samples.
• High throughput with a 20-minute run time inclusive of column wash and re-equilibration.
• Field-upgradeable platform allowing future sensitivity enhancements.

Future Trends and Potential Applications

Anticipated developments include expanding the list of target PFAS, achieving lower detection limits through high-resolution or next-generation triple quadrupole platforms, and integrating automated SPE and isotope dilution techniques. Advances in ambient ionization and real-time monitoring could further streamline environmental surveillance.

Conclusion

The Shimadzu LCMS-8050 meets and surpasses EPA draft Method 1633 performance criteria for PFAS quantitation in aqueous and wastewater matrices, delivering sensitivity, accuracy, and robustness required for routine environmental monitoring.

References

1. United States Environmental Protection Agency. Draft Method 1633: Analysis of Per- and Polyfluoroalkyl Substances in Aqueous, Solid, Biosolids, and Tissue Samples by LC/MS/MS, 2022.