Characterization of The Permeation Properties of Membrane Filters and Sorption Properties of Sorbents Used for Polar Organic Chemical Integrative Samplers

Abstract Polar organic chemical integrative samplers (POCIS) are promising devices for measuring the time-weighted average concentrations of hydrophilic compounds in aquatic environments. However, the mechanisms underlying compound uptake by POCIS remain unclear. We investigated the permeation kinetics of polyethersulfone and polytetrafluoroethylene membrane filters, and the sorption kinetics of Oasis HLB (Waters), Envi-Carb (Supelco), and Oasis WAX (Waters) sorbents. The log octanol−water partition coefficient (KOW) values of the 19 targeted compounds ranged from −0.55 to 6.0. The overall mass-transfer coefficients were negatively correlated with KOW, indicating that interactions between hydrophobic compounds and the membrane inhibit permeation. The sorption rate coefficient showed no correlation with KOW and depended on the type of sorbent used. These results imply that the uptake of highly hydrophilic compounds by POCIS is determined by both the membrane and the sorbent kinetics; however, membrane kinetics dominate the uptake of hydrophobic compounds. Environ Toxicol Chem 2024;43:2115–2121. © 2024 SETAC Design of this study. Sorption rate coefficients (s; g s–1) and overall mass transport coefficients (ko; m3 s–1) were obtained from sorption and permeation experiments, respectively. Kinetic factors (F; a.u.) were calculated as F=sVkomp where V (m3) is the volume of water and mp (g) is the mass of sorbent in the polar organic chemical integrative samplers (POCIS). High F values indicate that uptake by POCIS dominated by membrane kinetics. Kow(L kg−1) = octanol-water partition coefficient.