Adsorption of per- and polyfluoroalkyl substances (PFAS) to containers

Abstract

Mass transfer of per- and polyfluoroalkyl substances (PFAS) to container walls during sample collection and storage or experimentation is an important source of error in PFAS analysis. To minimize this error, high-density polyethylene (HDPE) and polypropylene containers are widely used for PFAS studies. However, there is sparse data to justify these container polymer choices. In this study, we investigated the adsorption of six common PFAS (in single-analyte solutions and in mixtures) to containers (made of HDPE, polypropylene, glass, polyethylene terephthalate (PET), and polystyrene) at 4°C and 20°C. All the containers adsorbed PFAS from the aqueous phase regardless of temperature. PFAS adsorption from single-analyte solutions ranged from 3.89 ng/cm2 (for hexafluoropropylene oxide dimer acid, GenX) to 30.34 ng/cm2 (for perfluorooctanesulfonamide, FOSA). In the mixtures, the highest PFAS adsorption (total concentration = 55.73 ng/cm2) occurred in the polypropylene container. The general trend of PFAS adsorption from the mixture was polypropylene > HDPE > PET > glass > polystyrene. In addition, adsorption to polypropylene containers made by three different manufacturers was substantially different for long-chain PFAS. PFAS adsorption to containers was influenced by PFAS chemistry, container hydrophobicity, and temperature. The result shows that container characterization for PFAS adsorption is an important step in PFAS studies.