ANALYSIS OF PER/POLYFLUOROALKYL SUBSTANCES (PFASs) IN WATER - Agilent Ultivo Triple Quadrupole LC/MS System

Importance of Topic

The widespread use of per- and polyfluoroalkyl substances (PFASs) in industrial and consumer products has led to their pervasive presence in environmental waters. Due to their persistence and potential health impacts, regulatory limits for PFASs in drinking water have been promulgated, driving the need for sensitive, accurate, and efficient analytical methods.

Objectives and Study Overview

This study presents a rapid, single-run method for quantifying 17 PFASs—including the 14 analytes specified in EPA Method 537—in drinking water. By coupling Agilent’s micro-footprint Ultivo Triple Quadrupole LC/MS system with optimized sample preparation, the goal was to achieve low-level detection, robust performance, and simplified maintenance.

Methodology and Instrumentation

Sample Preparation:

• Extraction of 250 mL water samples using Agilent SampliQ Weak Anion Exchange (WAX) cartridges.
• Elution and final reconstitution in 96/4 methanol/water following EPA 537 guidelines.

Liquid Chromatography and Mass Spectrometry Conditions:

• LC: Agilent 1290 Infinity II, ZORBAX Eclipse Plus C18 guard and analytical columns, 5 µL injection, 50 °C, 0.4 mL/min flow.
• Gradient: 10 % to 100 % methanol (5 mM ammonium acetate) over 19 minutes.
• MS: Agilent Ultivo Triple Quadrupole, negative-mode ESI, optimized gas and sheath temperatures, MRM transitions for 17 PFASs.

Main Results and Discussion

Instrument Performance:

• Sharp chromatographic peaks for all 17 PFASs at 1 ng/mL concentration.
• Retention time stability with RSDs <1 % for key analytes.

Linearity and Sensitivity:

• Seven-point calibration (0.1–20 ng/mL) yielded R² > 0.99 for all target PFASs.

Precision and Recovery:

• Intra-day precision (%RSD) below 5 % for most compounds at 1 µg/L post-spike (equivalent to 4 ng/L in water).
• Overall recovery between 70 % and 125 % with RSDs up to 10.8 % at two spike levels (1 and 5 µg/L).

Analysis of Real Samples:

• Detection of PFOS and PFOA at low ng/L levels in finished drinking water samples, confirming method sensitivity and applicability.

Benefits and Practical Applications

The method offers:

• High sensitivity for regulatory-level PFAS monitoring.
• Compact footprint and user-friendly operation, suitable for laboratories with limited MS expertise.
• Robust performance and reduced maintenance through integrated Ultivo innovations.

Future Trends and Potential Applications

Ongoing developments may include:

• Expansion to additional emerging PFASs and transformation products.
• Automation and high-throughput sample handling workflows.
• Integration with data-analysis software and AI for real-time monitoring.
• Green sample-prep techniques to reduce solvent consumption and waste.

Conclusion

The Agilent Ultivo Triple Quadrupole LC/MS, paired with an efficient WAX-based extraction, delivers a reliable, sensitive, and streamlined solution for quantitative PFAS analysis in drinking water, addressing regulatory demands and laboratory throughput needs.

Reference

Agilent Technologies, Inc. Analysis of Per/Polyfluoroalkyl Substances (PFASs) in Water using the Ultivo Triple Quadrupole LC/MS System; Publication 5991-8156EN, June 22, 2017