Losses of Ultrashort- and Short-Chain PFAS to Polypropylene Materials

Losses of long-chain poly-/per-fluoroalkyl substances (PFAS) due to adsorption on polypropylene (PP) materials have been reported in the literature. However, there is a lack of information on losses of ultrashort-/short-chain PFAS to PP materials, particularly in environmentally relevant conditions. In this study, we evaluated the losses of ultrashort-chain perfluoropropionic acid (PFPrA) and two short-chain PFAS, viz., perfluorobutanoic acid (PFBA) and perfluorobutanesulfonic acid (PFBS), to PP. Losses up to 20 ± 1% were observed for the studied PFAS after 24 h from 100 μg/L solutions. Losses varied greatly between PP tubes of different brands, probably due to differences in the availability of adsorption sites. Several processes were involved in the adsorptive losses of the three compounds. For example, charge screening and hydrophobic interactions affected the behavior of PFBS and PFBA. Lower losses observed in methanol and wastewater can be explained by the higher PFAS solubility and competition with other organics, respectively. This study highlights that laboratory-specific PFAS losses shall be carefully considered as they can prevent accurate trace analysis of short-chain PFAS. Our results will also help to improve the accuracy of future monitoring and adsorption studies of ultrashort-/short-chain PFAS.