A critical evaluation and optimization of combustion ion chromatography (CIC) for total fluorine quantification in...

The presence of per- and polyfluoroalkyl substances (PFAS) in plastics is of increasing concern due to their persistence, and potential impacts on human health and the environment. Their assessment increasingly relies on measuring total fluorine (TF), particularly in view of emerging regulatory limits for packaging materials, for which no standardized method exists yet.

This study unveils previously unrecognized biases impacting the accuracy of total fluorine (TF) determination by combustion ion chromatography (CIC), arising from combustion conditions, furnace configuration, and sample preparation. These biases were elucidated using an innovative experimental setup, marking a significant advancement in the analytical approach. An optimized CIC method was established for reliable TF quantification across different plastic matrices (polypropylene (PP), polyethylene (PE), polyurethane (PU), acrylonitrile butadiene styrene (ABS)). Providing repeatability below RSD <7%, fluorine recoveries exceeding 80% for inorganic and polymeric fluorinated compounds, and a limit of quantification of 6 mg F/kg. The TF concentrations measured in plastics and recycled samples were consistent with results obtained by instrumental neutron activation analysis (INAA), with an average bias of less than 10%.

These results demonstrate that CIC can provide robust and comparable TF data for plastics when critical analytical biases are properly controlled, supporting its application in PFAS monitoring and recycling studies.