A Method for the Determination of Total Organic Fluorine and Its Correlation with PFAS Analysis

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

Prepared by C. Neslund
Eurofins Lancaster Laboratories Environmental, LLC, 2425 New Holland Pike, Lancaster, PA, 17601, United States


Contact Information: charlesneslund@eurofinsus.com; 717-556-7231

ABSTRACT

Background/Objectives. Estimates place the total possible number of per- and polyfluoroalkyl substances (PFAS) in excess of 4500 compounds. Considering that current targeted compound analyses offered by commercial labs may report as many as 40 or 50 specific compounds, it becomes apparent that we are only seeing a sliver of the possible total impact. Add to that the fact that most of the current analytical techniques only address the anionic forms of PFAS, ignoring cationic, zwitterionic and neutral forms, it seems that our total assessment of impact is significantly biased. Use of the Total Oxidizable Precursor (TOP) assay, potentially gives us a better handle on the unknown mass remaining from targeted compound analysis, but still does not address everything.
Approach/Activities. One of the analytical approaches that have been used extensively by our colleagues in Australia is the determination of Total Organic Fluorine (TOF). The application for determining TOF combines a total organohalogen analysis with ion chromatography and is therefore referred to as combustion ion chromatography. PFAS impacted samples are combusted and mineralized in a furnace at near 1100 C and the gaseous effluent is collected, and then chromatographed for fluoride ion by ion chromatography. An evaluation of the technique, advantages as well as pitfalls will be described, through comparison to the other analytical techniques described previously (targeted compound analysis and TOP assay) as well as qTOF analysis.
Results/Lessons Learned. The presentation will describe the set-up and validation of the CIC analysis towards the determination of TOF. Results from spiked PFAS samples will be compared to the targeted compound results a part of the validation. PFAS impacted samples will be compared to the TOF results as well as TOP assay results from those same PFAS impacted samples. Lastly, some correlation with regard to the presence of polymeric PFAS, in the midst of the non-polymeric forms typically analyzed for will be made.