title: Dispersive liquid-liquid microextraction based on the solidification of floating organic droplet for the determination of polychlorinated biphenyls in aqueous samples.
abstract: In the proposed method, an extraction solvent with a lower toxicity and density than the solvents typically used in dispersive liquid-liquid microextraction was used to extract seven polychlorinated biphenyls (PCBs) from aqueous samples. Due to the density and melting point of the extraction solvent, the extract which forms a layer on top of aqueous sample can be collected by solidifying it at low temperatures, which form a layer on top of the aqueous sample. Furthermore, the solidified phase can be easily removed from the aqueous phase. Based on preliminary studies, 1-undecanol was selected as the extraction solvent, and a series of parameters that affect the extraction efficiency were systematically investigated. Under the optimized conditions, enrichment factors for PCBs ranged between 494 and 606. Based on a signal-to-noise ratio of 3, the limit of detection for the method ranged between 3.3 and 5.4 ng L(-1). Good linearity, reproducibility and recovery were also obtained.
authors.affiliation: Key Laboratory of Pesticide and Chemical Biology, Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Dai
authors.forename: Jing
authors.initials: J
authors.lastname: Cheng
authors.forename: Guzalnur
authors.initials: G
authors.lastname: Matsadiq
authors.forename: Lu
authors.initials: L
authors.lastname: Liu
authors.forename: Jun-Kai
authors.initials: JK
authors.lastname: Li
mesh_terms: D005591:Chemical Fractionation / Q000379:methods*; D005618:Fresh Water / Q000032:analysis; D057230:Limit of Detection; D011078:Polychlorinated Biphenyls / Q000032:analysis / Q000302:isolation & purification*; D012997:Solvents; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000302:isolation & purification*
chemical_list: D012997:Solvents; D014874:Water Pollutants, Chemical; D014867:Water; D011078:Polychlorinated Biphenyls