Transfer Kinetics of Polar Organic Compounds over Polyethersulfone Membranes in the Passive Samplers Pocis and Chemcatcher

• Published in: Environmental science & technology Vol. 46; no. 12; pp. 6759 - 6766
• Main Authors: Vermeirssen, Etiënne L. M, Dietschweiler, Conrad, Escher, Beate I, van der Voet, Jürgen, Hollender, Juliane
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 19.06.2012
• Subjects: Analysis methods; Applied sciences; Aqueous chemistry; Chromatography, Liquid; Correlation analysis; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Kinetics; Membranes; Membranes, Artificial; Natural water pollution; Organic chemicals; Organic Chemicals - chemistry; Pollution; Pollution, environment geology; Polymers - chemistry; Sorption; Sulfones - chemistry; Tandem Mass Spectrometry; Water treatment and pollution; Passive detection; Polymeric membrane; Emerging contaminant; Sampler; Transfer factor; Ethersulfone polymer; Water pollution; Kinetics; Polar compound; Sampling; Organic compounds
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es3007854

Passive samplers for polar organic compounds often use a polyethersulfone (PES) membrane to retain the particulate sorbent material (e.g., in a POCIS; polar organic chemical integrative sampler) or to reduce the sampling rate and thus extend the kinetic regime (e.g., in a Chemcatcher). The transport kinetics over the PES membrane are evaluated here in a short-term (6 days) and a long-term (32 days) experiment with POCIS and Chemcatchers. Passive samplers were placed in a channel with flowing river water that was spiked with 22 organic chemicals including pharmaceuticals, pesticides and biocides; with logK ow (logarithmic octanol–water partitioning coefficient) values between −2.6 and 3.8. Samplers were removed at intervals and membranes and sorbent material were extracted and analyzed with LC-MS/MS. Uptake kinetics of the compounds fell between two extremes: (1) charged chemicals and chemicals of low hydrophobicity did not accumulate in PES and rapidly transferred to the sorbent (e.g., diclofenac) and (2) more hydrophobic chemicals accumulated strongly in the PES and appeared in the sorbent after a lag-phase (e.g., diazinon and diuron). Sorption kinetics were modeled with a three-compartment first-order kinetic model to determine uptake and elimination rate constants and partitioning coefficients. Water PES partitioning coefficients fitted with the model correlated well with experimentally determined values and logK ow. Sampling rates of Chemcatcher (0.02–0.10 L/d) and POCIS (0.02–0.30 L/d) showed similar patterns and correlated well. Thus the samplers are interchangeable in practical applications. Longer lag-phases may pose problems when calculating time-weighted average aqueous concentrations for short passive sampling windows and for a correct integrative sampling of fluctuating concentrations.