Non-Targeted PFAS Batch Analysis in Environmental Extracts Using Microflow LC-QToF MS/MS with Multi-Spray ESI

Emerging Environmental Applications for High Resolution Mass Spectrometry
Oral Presentation

Presented by O. Shrestha
Prepared by K. Luo, J. Ferguson, T. Liden, R. Suzuki
Shimadzu Scientific Instruments, 7102 Riverwood Drive, Columbia, MD, 21046, United States


Contact Information: [email protected]; 410-910-9959

ABSTRACT

Per- and polyfluoroalkyl substances (PFAS) comprise a large and structurally diverse class of environmental contaminants for which targeted screening methods alone are insufficient to detect emerging or transformative compounds. Non-targeted analysis (NTA) approaches require high sensitivity, high mass accuracy, and comprehensive fragmentation to sufficiently characterize PFAS in complex environmental matrices. In this study, a microflow LC-QToF MS/MS workflow coupled with a multi-nozzle electrospray ionization (ESI) source was optimized to enhance sensitivity and enable batch NTA screening of environmental extracts.
Samples were introduced using a microflow LC system coupled with a quadrupole time-of-flight mass spectrometer operating in negative ion mode. Data-independent acquisition (DIA) was employed to ensure comprehensive fragmentation. Environmental samples, including aqueous film-forming foam (AFFF) and AFFF-impacted soil extracts from the NIST non-targeted analysis interlaboratory study, and a separate extracted landfill leachate sample were analyzed. DIA datasets were processed using automated deconvolution, library screening, and elemental-formula prediction workflows, with elemental constraints applied to prioritize PFAS-like candidates using Shimadzu LabSolutions Insight Discovery.
Approximately 5,000 components were detected in the AFFF extract, including nine targeted PFAS and five compounds previously reported in the NIST study. Formula prediction generated 172 additional PFAS-like candidate features for further investigation. Application of the workflow to landfill leachate identified two PFAS (6:2 FTS and PFHxS) through combined target screening, library matching, and formula prediction. These results demonstrate that microflow LC-QToF MS/MS coupled with multi-spray ESI enables sensitive detection and streamlined batch processing for non-targeted PFAS screening in complex environmental samples.