Effect of Short-term Sample Storage and Preparatory Conditions on Losses of 18 Per- and Polyfluoroalkyl Substances (PFAS) to Container Materials

There is a lack of agreement on a suitable container material for per- and polyfluoroalkyl substances (PFAS) analysis, particularly at trace levels. In this study, the losses of 18 short- and long-chain (C4-C10) PFAS to commonly used labware materials (high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polypropylene co-polymer (PPCO), polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE), and glass were investigated. The influence of sample storage and preparation conditions, i.e., storage time, solvent composition, storage temperatures (4 ºC and 20 ºC), and sample agitation techniques (shaking and centrifugation) on PFAS losses to the container materials were investigated. The results showed higher losses for most of the considered PFAS (up to 50.9%) in 100% aqueous solutions after storage for 7 days regardless of the storage temperature compared to those after 3 days. Overall, the order of losses to different materials varied for individual PFAS, with the highest losses of long-chain PFAS observed to PP and HDPE after 7 days storage at room temperature. The addition of methanol to aqueous PFAS solutions reduced the losses of long-chain PFAS to all tested materials. The use of sample centrifugation and shaking did not influence the extent of n losses for most of the PFAS in 80:20 water:methanol (%, v/v) to container materials except for 8:2 fluorotelomer sulfonic acid (8:2 FTS), 9-chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9 Cl-PF3ONS), perfluorodecanoic acid (PFDA) and 4:2 fluorotelomer sulfonic acid (4:2 FTS). This study demonstrates lower losses of both long- and short-chain PFAS to glass and PET. It also highlights the need for caution when deciding on sample preparatory steps and storage during the analysis of PFAS.