Accurate Mass QToF - A New Direction in Quantitative PFAS Analysis

Polyfluoroalkyl Substances (PFAS) in the Environment (Session 4)
Oral Presentation

Prepared by K. Hunt, R. Hindle
Vogon Labs, 34 Griffin Industrial Pt, Cochrane, AB, T4C0A3, Canada


Contact Information: [email protected]; 403-770-9106

ABSTRACT

As the scientific community’s understanding of the persistent and harmful nature of Per- and Poly-Fluorinated Compounds (PFAS) increases so too does the need to move technology forward in their analysis. Traditionally triple quadrupole instruments have been used for the quantitative analysis of specified PFAS compounds, but as new compounds are discovered, accurate mass instruments will be needed to both identify and quantitate them.

This presentation will demonstrate flexibility in PFAS analysis with emphasis on the variety of techniques available on high resolution accurate mass QTOF instrumentation. USEPA 533 extraction method and compounds are used as an example case to present the work.

Targeted MSMS acquisition is most like triple quadrupole analysis, which traditional PFAS analysts will be comfortable with, the precursor ions are isolated by the quadrupole and accurate mass product ions are identified by time-of-flight mass spectrometry. Quantitation occurs on the transition from a precursor to a product ion. Labeled internal standards and isotope dilution analogues may be used without problem. Results show LCMRL values near or below those published in the USEPA method with good reproducibility, while maintaining MS level spectra for retrospective analysis of untargeted PFAS.

Moving from targeted to data-independent acquisition, All Ions technique produces unfiltered full scan spectra at multiple collision energies allowing for simultaneous collection of both precursor and fragmentation data. Quadrupole Resolved All Ions acquisition provides some precursor ion filtration with user defined quadrupole windows and fragmentation occurring in in the collision cell. In both, quantitation takes place on ions from the zero collision energy data while fragmentation ions from higher energy spectra with acceptable coelution scores serve as qualifiers. Results show low detection limits with reproducible chromatography and sub-2 ppm mass accuracy. These data-independent acquisition modes provide spectra suitable for discovery of untargeted PFAS as well as quantitation of targeted compounds.