Presentation Profile
Optimizing Thermal Desorption GC-MS/MS for the Analysis of Volatile PFAS via a new ASTM Standard Method
Currently Scheduled: 10/15/2024 - 9:00 AM - 9:20 AM
Room: Bluebonnet
Main Author
Kurt Thaxton - GERSTEL GmbH
- Jochen Vandenberg - GERSTEL GmbH
- Jack Stuff - GERSTEL Inc.
- Jackie Whitecavage - GERSTEL Inc.
Abstract:
Volatile PFAS concentrations in air, like their water counterparts, can be in the low ppb to ppt (V/V) range. To enable detection at these low levels, large volumes of air need to be sampled (50+ Liters). Alternately, for time weighted average sampling, long sampling times are advantageous, but this also leads to large amounts of air sampled. Possible sources of unwanted gain or loss of PFAS species at these low levels must also be anticipated and removed if possible.
Thermal Desorption, where air is drawn onto sorbent-filled tubes and later analyzed using gas chromatography – mass spectrometry (GC-MS), is an ideal technique for large volume sampling and works well in either case above. However, large amounts of matrix are also drawn into the tubes as well and can present issues with both carryover and interference with analyte signals. Gas chromatography - tandem mass spectrometry (GC-MS/MS) largely eliminates these interferences as well as chemical noise in general. The elimination of this noise also lowers detection limits, which for PFAS in air is advantageous.
This approach has now been codified into an ASTM method within the D22.05 Indoor Air Quality subcommittee and is now being validated by a multi-laboratory, multi-national interlaboratory study (ILS). This presentation will discuss how and why this method was developed and the progress of the ILS validation of the method, as well as insights into sampling strategies and other means of dealing with PFAS contamination.
