Sorption of per‐ and polyfluoroalkyl substances (PFASs) on filter media: Implications for phase partitioning studies

Abstract

Per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), are ubiquitous in the environment. Investigations into their fate and potential phase-partitioning behavior require separating solid from aqueous phases via filtration. However, sorption of aqueous-phase PFASs on filtration media may lead to underestimation of PFAS concentrations in the aqueous phase. The authors investigated the sorption of perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, perfluoroalkyl phosphonic acids, perfluoroalkyl phosphinic acids (PFPiAs), polyfluoroalkyl phosphate monoesters, polyfluoroalkyl phosphate diesters (diPAPs), fluorotelomer sulfonates, and perfluorooctane sulfonamide on filtration media. The effects of concentration (3 spiking levels), filter media (4 types), matrix (4 matrices), and compound structure on sorption are reported. Glass fiber filtration resulted in the least sorption, whereas polytetrafluoroethylene filters resulted in the most sorption (up to 98%). Analyte concentration had no significant effect. Sorption was generally consistent across matrix types except for samples affected by aqueous film forming foam deployment, which displayed high sorption of PFOS on nylon filters. Sorption usually increased with an increasing number of carbon or fluorine atoms and was most pronounced for PFPiAs and diPAPs (30–75% sorption). Overall, glass fiber filters are more recommended than nylon filters in environmental samples when phase separation is required. Use of filtration media for PFAS must be preceded by matrix-specific testing to account for unpredictable effects.

Spatial variation in the atmospheric deposition of perfluoroalkyl acids: source elucidation through analysis of isomer patterns

“…† The use of internal standard accounts for matrix effects and for sorptive losses, which may arise during storage and ltration. 52,53 However, concentrations of PFDoDA, PFTriDA, PFTeDA and PFDS are not reported in this study as their corresponding internal standard ( 13 C 2 -PFDoDA) exhibited poor recovery (<20%) in a majority of the samples. Furthermore, in two thirds of the Swedish samples, reported concentrations of PFUnDA are associated with a higher uncertainty as the recovery of their corresponding internal standard ( 13 C 2 -PFUnDA) was poor (<30%).…”

Can determination of extractable organofluorine (EOF) be standardized? First interlaboratory comparisons of EOF and fluorine mass balance in sludge and water matrices

“…The variation seen in PFAS-16 concentrations is likely attributable to the fact that no internal standard is used for the quantification. The lower EOF concentrations produced by SU in GWhigh may be due to filtering groundwater samples prior to extraction, (not done by ORU and IVL for groundwater), and which may have resulted in loss of some unidentified PFAS due to sorption to filters 31 or suspended solids. 32 The target PFAS results, on the other hand, did not follow the same pattern as EOF and seems therefore unaffected by the filtration difference.…”

Influence of Environmental Factors on the Fate of Legacy and Emerging Per- and Polyfluoroalkyl Substances along the Salinity/Turbidity Gradient of a Macrotidal Estuary

“…The impact of filter nature on this filtration artifact has been previously examined for a suite of anionic PFASs, showing that glass, rather than nylon, would better preserve the integrity of dissolved phase concentrations. 61,62 Chandramouli et al 62 cautioned, however, that significant filtration artifacts could still be obtained with glass filters for particular analytes, including diPAPs.…”