The challenges

Finding a tool that:

• Enables comprehensive detection of poly- and perfluoroalkyl substances (PFAS)
• Delivers compound-specific information, such as fragmentation information for structural elucidation of unknown species
• Facilitates the identification of a broad suite of PFAS

The solution

We used a mixed mode liquid chromatography (LC) separation with high-resolution mass spectrometry and data-independent fragmentation. We first applied polar phase separation chemistry, which we switched out depending on our anionic, cationic or zwitterionic targets, and then a non-polar phase (typically a C18 phase) for analytical separation.

A quadrupole time-of-flight (QTOF) mass spectrometer allows simultaneous:

• Targeted analysis: Quantification with standards and mass labeled surrogates available
• Suspect screening: Semi- quantification of suspect compounds (previously identified compounds without reference standards)
• "True" non-target analysis: Identification of novel compounds and candidate structures from accurate mass and fragmentation information

The outcomes

• LC-QTOF-MS/MS provides a means to investigate novel or previously uncharacterized PFAS, while simultaneously performing targeted and suspect screening analyses
• Suspect screening identified 167 PFAS from 37 classes in soils and soil effluents from aqueous film-forming foams (AFFF)