Simultaneous Quantification of Multiclass PFAS in Biosolids Using a Single Extraction Method and the Agilent 6495 Triple Quadrupole LC/MS

Significance of the Topic

Per- and polyfluoroalkyl substances (PFAS) persist in the environment and accumulate in biosolids used as soil amendments, posing ecological and health risks. Accurate quantification at trace levels is essential to assess contamination and guide management practices.

Objectives and Study Overview

This study aims to develop and validate a streamlined extraction and analysis workflow for 44 PFAS across nine classes in biosolids, using a single extraction method coupled with Agilent 1290 Infinity II LC and 6495 triple quadrupole MS. The method was tested on 19 real-world biosolid samples from various wastewater treatment plants in Australia.

Methodology

Biosolid samples were homogenized, freeze-dried, and ground. A 0.5–1 g aliquot was spiked with isotopically labeled surrogates and extracted with 10 mM NaOH in methanol. Samples underwent sonication, overnight shaking, neutralization, and cleanup with C18 and PSA sorbents, followed by filtration and analysis in batches including blanks and controls for recovery determination.

Instrumental Setup

An Agilent 1290 Infinity II LC equipped with a ZORBAX Eclipse Plus RRHD C18 column performed gradient separation using 5 mM ammonium acetate in water and methanol. Detection was by Agilent 6495 triple quadrupole MS with negative ESI and optimized MRM transitions. A delay column and PEEK tubing minimized background contamination.

Main Results and Discussion

Method recoveries for control samples at 2 ng/g ranged between 70 % and 130 % for most PFAS. All 44 target compounds were detected in real biosolids, with total PFAS levels ranging from 4.2 to 910 ng/g (mean 260 ng/g). Perfluorocarboxylic and sulfonic acids were most prevalent, while phosphinic acids and ether PFAS appeared less frequently.

Benefits and Practical Applications

The single-extraction protocol and rapid 15-minute LC/MS run enable efficient, sensitive, and robust multiclass PFAS quantification in complex biosolid matrices. This approach supports environmental monitoring, risk assessment, and regulatory compliance in wastewater and agricultural reuse applications.

Future Trends and Potential Applications

Advances may include expanding analyte scope to novel PFAS chemistries, integrating high-resolution MS for non-target screening, and automating sample preparation. Broader application across soil and sludge matrices will further elucidate PFAS fate and transport.

Conclusion

The described method offers a reliable, high-throughput solution for simultaneous quantification of a wide range of PFAS in biosolids. Its strong recovery performance and applicability to diverse real samples make it a valuable tool for environmental analytical laboratories.

References

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