1. Isotopic exchange on solid-phase micro extraction fiber in sediment under stagnant conditions: Implications for field application of performance reference compound calibration.
- Author
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Bao, Lian-Jun, Wu, Xiaoqin, Jia, Fang, Zeng, Eddy Y, and Gan, Jay
- Subjects
Animals ,Polychaeta ,Deuterium ,Water ,Carbon Isotopes ,Polychlorinated Biphenyls ,Dichlorodiphenyl Dichloroethylene ,Dimethylpolysiloxanes ,Water Pollutants ,Chemical ,Calibration ,Environmental Monitoring ,Geologic Sediments ,Solid Phase Extraction ,Hydrophobic organic compounds ,Nonsymmetrical relationship ,Passive sampling ,Performance reference compound calibration ,Stagnant sediment ,Environmental Sciences ,Chemical Sciences ,Biological Sciences - Abstract
An overlooked issue for field application of in situ performance reference compound (PRC) calibration methods is the validity of the assumption that both the sorption of a target compound and desorption of its corresponding PRC follow the first-order kinetics with the same rate constants under stagnant conditions. In the present study, disposable polydimethylsiloxane fibers of 2 sizes (7 and 35 µm) impregnated with 8 (13) C-labeled or deuterated PRCs were statically deployed into different marine sediments, from which the kinetics for sorption of the target compounds and desorption of the PRCs were characterized. Nonsymmetrical profiles were observed for exchange of the target analytes and their corresponding PRCs in sediment under stagnant conditions. The hysteretic desorption of PRCs in the kinetic regime may be ascribed to the low chemical potential between the fiber and sediment porewater, which reflects the inability of water molecules to rapidly diffuse through sediment to solvate the PRCs in the aqueous layer around the fiber surface. A moderate correlation (r = 0.77 and r = 0.57, p
- Published
- 2016