Time-Integrative Passive Sampling of Very Hydrophilic Chemicals in Wastewater Influent

Passive sampling of very hydrophilic chemicals is challenging due to the weak adsorption affinity to commonly used sorbent phases. Here we present a technique for the passive time-integrative sampling of highly water-soluble chemicals in wastewater influent, using a new diffusion-based sampling device. The sampler is a sealed chamber covered at one end by a porous polyethylene membrane, allowing chemicals to diffuse through the water-filled pores into the receiving phase of water. When submerged, the concentration gradient drives diffusion into the sampler, increasing the concentration of analytes in the receiving phase over time. To calibrate and test sampler performance, the sampler was deployed in wastewater influent for 31 d. The accumulation of acesulfame, ethyl sulfate, methamphetamine, and benzoylecgonine into the sampler was modeled using simultaneously collected 24 h composite samples. The four chemicals are typically monitored in wastewater-based surveillance programs and ranged in log K-ow from -2.49 (ethyl sulfate) to 2.22 (methamphetamine). In situ calibration showed linear increases in concentration over the deployment period, and calculated sampling rates ranged from 2.2 mL d(-1) (methamphetamine) to 4.0 mL d(-1) (ethyl sulfate). This technique is useful for the time-integrative sampling of a range of hydrophilic chemicals in wastewater and shows potential for other aquatic matrices.