Comprehensive Evaluation of the Analytical Efficiency of Combustion Ion Chromatography for Per- and Polyfluoroalkyl Substances in Biological and Environmental Matrices

Combustion ion chromatography (CIC) has emerged as a valuable tool for determining fluorine content attributable to per- and polyfluoroalkyl substances (PFAS) in biological and environmental samples. The total organofluorine (TOF) data from CIC complement information obtained by targeted analyses using liquid chromatography-tandem mass spectrometry (LC-MS/MS) because TOF includes PFAS that may not be captured by targeted techniques. However, the effect of different PFAS types (chain lengths, head groups, etc.) and matrices on combustion efficiency has not been systematically evaluated. Comparison of C₄-C₁₂ PFAS using equimolar quantities of fluorine (5.27 nmol F) demonstrated statistically equivalent CIC responses, indicating uniform combustion across chain lengths. Further, signals resulting from combustion times ranging from 7.5 to 15 min were statistically equivalent. However, fluorotelomer alcohols (FTOHs) exhibited losses due to volatility, requiring the use of an activated carbon sorbent to improve analytical signals. Matrix variations exhibited no change in PFAS combustion efficiency across chain lengths in water, blood, and biosolids. Total fluorine results from CIC analysis of real blood and biosolid samples were compared to targeted LC-MS/MS results. This study highlights the strengths and limitations of CIC as an important complement to targeted PFAS analysis and provide guidance for optimizing application-specific conditions and interpreting CIC results.