Work

Validation of a suspect screening and semi-quantitation workflow for broad suite of PFAS in environmental matrices

Year: 2026

Type: article

Abstract: ABSTRACT As the use of suspect screening analysis becomes more routine for the investigation of per- and polyfluoroalkyl substances (PFAS), method robustness becomes paramount. Possible causes of variation in the workflow include inter-day, intra-day, analyst-to-analyst and matrix-to-matrix variance. Reproducibility was assessed using two water matrices, two levels of in-house spikes as well as an aqueous film-forming foam (AFFF) spike, across four days and two analysts, with each sample analyzed in triplicate. Sample extraction was assessed by analyzing samples spiked before and after an extraction. Analysis was performed on a liquid chromatography quadrupole time-of-flight mass spectrometer (LC-QToF/MS) system in both electrospray positive and negative modes (ESI±) followed by data processing and confidence level assignments. The extraction efficiency and number of target and suspect PFAS detections between EPA Method 1633 and the legacy extraction method for PFAS in soil showed that Method 1633 provided enhanced sensitivity and detected a substantially greater number and broader range of PFAS, while both methods shared many common detections. Accuracy was assessed on the pre- and post-spiked samples that contained a known mixture of PFAS analytes and was found to be acceptable in terms of false positive rates. Precision was found to be acceptable in intra-day (88.9% to 100%), inter-day (95±4%) and analyst-to-analyst (relative standard deviation of 0 – 0.5%). Comparison of pre- and post-spiked samples analyzed in ESI positive mode suggests the WAX SPE cartridge was sufficient for processing a wider range of analytes, including zwitterionic and cationic PFAS. The findings herein demonstrate that the suspect screening workflow for suspect PFAS, which incorporates robust extraction and analytical methods, delivers reliable and reproducible results across multiple sources of variance, including matrix, analyst, and day-to-day differences. The enhanced sensitivity and broader analyte coverage provided by EPA Method 1633, combined with comprehensive data processing and confidence level assignments, support Method 1633’s sample extraction method suitability for suspect screening analysis applicable for routine PFAS investigations in both water and soil matrices. Using “expert-selected surrogate” semi-quantitation approach applied in the current study for broader suite of suspect analytes demonstrates improved accuracy and reliability, and decreased uncertainty. Overall, the study herein underscores the importance of method selection and validation for achieving high confidence for suspect PFAS identified following the high-resolution mass spectral analysis workflows.

Source: Journal of Hazardous Materials Advances

DOI: 10.1016/j.hazadv.2026.101517