Teflon-water partitioning coefficients of per- and polyfluoroalkyl substances for passive sampler development

Per- and polyfluoroalkyl substances (PFAS) contamination in the aqueous environment is of global concern due to its strong durability and bioaccumulation as well as its harmful effects on human health. However, its distribution and variability in extreme environments are yet to be studied. In order to further understand the fate of this contaminant and to determine whether there are factors from extreme environments can break down this group of substances, it is necessary to develop a technique that facilitates the detection of a wide range of PFAS in special environments. Given the strong chemical and thermal stability of Teflon material and its close relationship with PFAS, this study aims to determine the ability of this material as a PFAS targeting passive sampler. Two Teflon materials, PTFE and FEP, were selected for triplicate experiments at five different exposure times (1 h, 6 h, 24 h, 96 h, and 168 h) × five different initial water concentrations (5 ng/ml, 10 ng/ml, 25 ng/ml, 50 ng/ml and 100 ng/ml) to determine Teflon-water partitioning. Sample concentrations of 11 common PFAS (L-PFHxS, PFHxA, PFHpA, PFOA, PFOS, PFNA, PFDA, PFUdA, PFDoA, PFTrDA, PFTeDA) were analyzed using liquid-chromatography/tandem mass spectrometry (LC-MS/MS) method, and mass based Teflon-water partitioning coefficients (KTeflon,w) of these compounds were calculated (ranging from 0.12 to 2.65). The adsorption isotherms performed to calculate the partition coefficients showed linear behavior. Long-chain PFAS (more than 7 C-C bonds) showed a stronger linear correlation on FEP materials while short-chain PFAS (4-7 C-C bonds) showed a stronger linear correlation on PTFE materials.--Author's abstract