Speaker: Adam Schanen, M. Sc

Due to their environmental persistence and potential human health implications, the analysis of per- and polyfluoroalkyl substances (PFAS) remains critical. Targeted analysis using LC-MS/MS, while sensitive and specific, often falls short in assessing the total impact of PFAS due to the vast number of potential compounds. Non-targeted analysis techniques, such as quantifying total organic fluorine (TOF), have emerged as valuable tools for a more comprehensive PFAS assessment.

Combustion Ion Chromatography (CIC) is a powerful technique for sensitive TOF quantitation, covering a wide range of concentrations, from single-digit ppb to percent levels. In CIC, samples are combusted to release organic fluorine as hydrogen fluoride (HF), which is subsequently analyzed by ion chromatography. TOF analysis is unique in its ability to directly inject liquid samples into the combustion tube. This "catch-all" approach allows for the analysis of a wide range of organic fluorine compounds, including both known and unknown PFAS. By directly combusting the sample, CIC can capture a broader spectrum of fluorine-containing compounds compared to other techniques that rely on pre-concentration steps. TOF analysis also incorporates direct-inject IC measurement of the inorganic fluoride background yielding a useful tool for monitoring fluorine mass balance in PFAS destruction technologies.

Various techniques exist for inorganic fluoride removal, each with its own advantages and limitations. The adsorbable organic fluorine (AOF) method, standardized in US EPA Method 1621, involves capturing organic fluorine on activated charcoal and removing inorganic fluoride through rinsing. Other methods, such as extractable organic fluorine (EOF) and total fluorine (TF), have also been explored EOF and TF can be particularly useful for the analysis of fluorine species in consumer products and biological samples, providing insights into potential exposure pathways and health risks.

This presentation will compare these different techniques, highlighting their strengths, weaknesses, and applicability for non-targeted PFAS analysis. By understanding the distinctions between TOF, EOF, TF, and AOF, researchers can select the most appropriate method for their specific analytical needs and contribute to a more comprehensive assessment of PFAS contamination.