John Wiley & Sons, Ltd.

Automated method for determination of dissolved organic carbonwater distribution constants of structurally diverse pollutants using pre‐equilibrium solid phase microextraction

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Dissolved organic carbon (DOC) plays a key role in determining the environmental fate of semi‐volatile organic environmental contaminants. The goal of the present work was to develop a method using commercially available hardware to rapidly characterize the sorption properties of DOC in water samples. The resulting method uses negligible‐depletion direct immersion solid‐phase microextraction (nd‐SPME) and gas chromatography – mass spectrometry (GC‐MS). Its performance was evaluated using Nordic Reference fulvic acid and 40 priority environmental contaminants that cover a wide range of physicochemical properties. Two SPME fibers had to be used to cope with the span of properties, one coated with polydimethylsiloxane (PDMS) and the other one coated with polystyrene divinylbenzene (PS‐DVB) PDMS, for nonpolar and semi‐polar contaminants, respectively. The measured DOC – water distribution constants (KDOC) showed reasonably good reproducibility (SD ≤ 0.32) and good correlation (R2 = 0.80) with log KOW values for nonpolar persistent organic pollutants. The sample pre‐treatment is limited to filtration and the method is easy to adjust to different DOC concentrations. These experiments also utilized the latest SPME automation that largely decreases total cycle time (to 20 minutes or shorter) and increases sample throughput, which is advantageous in cases when many samples of DOC have to be characterized or when the determinations have to be performed quickly, e.g. to avoid precipitation, aggregation and other changes of DOC structure and properties. The data generated by this method are valuable as basis for transport and fate modeling studies. This article is protected by copyright. All rights reserved

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