Analysis of per/polyfluoroalkyl substances (PFASs) in drinking water using the Agilent Ultivo triple quadrupole LC/MS

Importance of the topic

Per- and polyfluoroalkyl substances (PFASs) are persistent environmental contaminants linked to adverse health effects, including developmental, hepatic, renal, and immunological damage. Regulatory agencies like the US EPA and various states have set stringent advisory and guideline levels (as low as 14–70 ng/L combined for PFOA and PFOS) in drinking water. Reliable, high-throughput analytical methods are critical for monitoring these compounds at trace levels and ensuring public health protection.

Objectives and study overview

This study aimed to develop and validate a rapid, sensitive LC/MS/MS method for quantifying 17 PFASs—encompassing the 14 analytes listed in US EPA Method 537—using the compact Agilent Ultivo triple quadrupole mass spectrometer. Key goals included:

• Meeting or exceeding EPA Method 537 performance criteria
• Reducing analysis time and injection volume
• Demonstrating repeatability and linearity over a wide concentration range
• Applying the method to real drinking water samples

Methodology and instrumentation

Sample preparation followed US EPA Method 537 solid-phase extraction using Agilent SampliQ WAX cartridges on 250 mL water samples. Extracts were concentrated to dryness, reconstituted in 96:4 methanol:water, and spiked with isotopically labeled internal standards. An Agilent 1290 Infinity II LC system with a delay column and an analytical ZORBAX Eclipse Plus C18 column (3.0 × 50 mm, 1.8 μm) was used. The mobile phase consisted of 5 mM ammonium acetate in water (A) and 95% methanol (B), at 0.4 mL/min, with a 16.5-minute gradient. The Agilent Ultivo triple quadrupole with Jet Stream ESI source operated in negative ion mode using dynamic multiple reaction monitoring (dMRM). The stackable design of Ultivo reduced the lab footprint while maintaining robust performance.

Main results and discussion

The method achieved:

• Run time of 16.5 minutes versus 35–37 minutes in EPA Method 537
• Injection volume of 5 μL (half of the EPA method)
• Limits of quantification below EPA and state guideline levels
• Linear calibration (0.2–100 ppb) with R² > 0.99 for all 17 analytes over one month
• Continuous calibration verification (11 samples at 1 ppb over 26 hours) with %RSD < 5% for all but one analyte
• Successful detection of PFBS (10 ng/L), PFOS (4 ng/L), PFOA (0.6 ng/L), and PFNA (8 ng/L) in real drinking water samples

These results demonstrate excellent sensitivity, reproducibility, and throughput improvements, while effectively controlling system background from fluoropolymer components.

Benefits and practical applications

The optimized method offers:

• Enhanced sample throughput with shorter run times
• Reduced solvent and sample consumption
• High sensitivity suitable for regulatory compliance
• Compact instrument footprint facilitating integration in routine QA/QC labs

This approach supports environmental monitoring, regulatory testing, and industrial water quality control for PFAS contamination.

Future trends and potential uses

Advancements may include:

• Expansion to emerging and ultra-short-chain PFAS analytes
• Further miniaturization and automation of sample prep workflows
• Integration with high-resolution MS for non-targeted PFAS screening
• On-site or portable PFAS detection systems for rapid field analysis
• Application in wastewater, soil, and biota monitoring to assess environmental fate

Conclusion

The Agilent Ultivo-based LC/MS/MS workflow delivers a robust, high-throughput solution for quantifying 17 PFASs in drinking water, surpassing US EPA Method 537 criteria. It provides rapid analysis, low detection limits, excellent reproducibility, and reduced laboratory footprint, making it highly suitable for regulatory and research laboratories focused on PFAS monitoring.

References

1. United States Environmental Protection Agency. Research on Per- and Polyfluoroalkyl Substances (PFAS). Retrieved October 11, 2017, from https://www.epa.gov/chemical-research/research-and-polyfluoroalkyl-substances-pfas
2. US EPA Method 537. Determination of Selected Perfluorinated Alkyl Acids in Drinking Water by Solid Phase Extraction and LC/MS/MS. Version 1.1, September 2009. J.A. Shoemaker, Office of Research and Development.
3. Anumol, T.; Yang, D.-H. D.; Sosienski, T.; Batoon, P. Recommended Plumbing Configurations for Reduction in Per/Polyfluoroalkyl Substance Background with Agilent 1260/1290 Infinity (II) LC Systems. Agilent Technologies Application Note 5991-7863EN.