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

Abstract

<p>Polar organic chemical integrative samplers (POCIS) are promising devices for measuring time-weighted average concentrations of hydrophilic compounds in aquatic environments. However, the mechanism of POCIS uptake remains unclear. This study characterizes the permeation properties of polyethersulfone and polytetrafluoroethylene and the sorption properties of Oasis HLB (Waters), Envi-Carb (Supelco), and Oasis WAX (Waters) under identical conditions via calibration experiments of the POCIS. Plant protection products, neonicotinoid herbicides, and linear alkyl benzene sulfonates (LAS) were tested. The permeation experimental results suggested that the penetration rate constants (<i>k</i><sub>m</sub>) with high <i>K</i><sub>ow</sub> values (<i>K</i><sub>ow</sub>: octanol–water partition coefficient) were low, which indicated that the sorption of chemicals on the membrane may constitute a limiting factor for the permeation. The sorption experiments indicated that the sorption rate constants (<i>k</i><sub>s</sub>) depended on the type of sorbent instead of the <i>K</i><sub>ow</sub> values. Low <i>k</i><sub>s</sub>/<i>k</i><sub>m</sub> ratios were obtained for chemicals with low <i>K</i><sub>ow</sub> values, which implied that the POCIS uptake for highly hydrophilic compounds was controlled by both membrane and sorbent kinetics. The <i>k</i><sub>m</sub> and <i>k</i><sub>s</sub> values corresponded to the model and predicted the values of the sampling rates<i> </i>(<i>R</i><sub>s</sub>) for the LAS. These findings revealed the possibility of using <i>k</i><sub>s</sub> and <i>k</i><sub>m</sub> values to predict <i>R</i><sub>s</sub> values.</p>

Development and Evaluation of the Performance of the Polar Organic Chemical Integrative Sampler for Linear Alkylbenzene Sulfonate

“…When the dry POCIS devices were deployed in the solution, the water penetrated into the POCIS device which enhanced the permeation of the LASs [23]. The effect was found in the previous study using the POCIS devices with glass bars to estimate the permeation rate [23]. The effect has not been considered, because the lag-time may counteract.…”