title: Development of a new time-integrative sampler using in situ solvent extraction.
abstract: Despite the great success of time-weighted average passive sampling of hydrophobic contaminants, such as PCBs and PAHs, the sampling of polar organic compounds still presents a challenge because the equilibrium between water and most sampling phases is attained in a relatively short time. In this study, we proposed a new time-integrative sampler using in situ solvent extraction (TISIS) for polar organic chemicals. The sampler was composed of a 15 cm poly(dimethylsiloxane) (PDMS) tubing, with an internal diameter of 0.5 mm and wall thickness of 0.5 mm, through which an extraction solvent (acetonitrile) was passed. Four polar organic contaminants, caffeine, atrazine, diuron and 17α-ethynylestradiol, were chosen for the evaluation of the performance of the sampler. Without the use of in situ solvent extraction, the PDMS tubing when exposed to a constant aqueous concentration of the four model compounds was able to linearly accumulate those compounds for less than 12 h and equilibrium between the PDMS tubing and water was attained in 2 d under our laboratory conditions. However, TISIS when exposed to a constant aqueous concentration was able to linearly accumulate all the model compounds without any exposure time limitation. The measured sampling rates at three different extraction flow rates (0.2, 0.5, 1.5 mL min(-1)) were similar, regardless of the chemicals, indicating that the overall mass transfer from aqueous solution to the extraction solvent was most likely dominated by partitioning to the PDMS tubing and the internal diffusion within PDMS. In addition, a pulsed exposure experiment confirmed that TISIS operated in a time-integrative mode when the environmental concentration was highly fluctuated.
authors.affiliation: Department of Environmental Engineering, Ajou University, Woncheon-dong, Yeongtong-gu, Suwon 443-749, Republic of Korea. jhkwon@ajou.ac.kr
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Kwon
authors.forename: Min-Ji
authors.initials: MJ
authors.lastname: Kim
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Kim
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004784:Environmental Monitoring; D004867:Equipment Design; D008962:Models, Theoretical; D011078:Polychlorinated Biphenyls / Q000737:chemistry; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013997:Time Factors
chemical_list: D004129:Dimethylpolysiloxanes; D011084:Polycyclic Aromatic Hydrocarbons; D012997:Solvents; C013830:baysilon; D011078:Polychlorinated Biphenyls