title: Determination of cadmium(II), cobalt(II), nickel(II), lead(II), zinc(II), and copper(II) in water samples using dual-cloud point extraction and inductively coupled plasma emission spectrometry.
abstract: A dual-cloud point extraction (d-CPE) procedure has been developed for simultaneous pre-concentration and separation of heavy metal ions (Cd2+, Co2+, Ni2+, Pb2+, Zn2+, and Cu2+ ion) in water samples by inductively coupled plasma optical emission spectrometry (ICP-OES). The procedure is based on forming complexes of metal ion with 8-hydroxyquinoline (8-HQ) into the as-formed Triton X-114 surfactant rich phase. Instead of direct injection or analysis, the surfactant rich phase containing the complexes was treated by nitric acid, and the detected ions were back extracted again into aqueous phase at the second cloud point extraction stage, and finally determined by ICP-OES. Under the optimum conditions (pH=7.0, Triton X-114=0.05% (w/v), 8-HQ=2.0×10(-4) mol L(-1), HNO3=0.8 mol L(-1)), the detection limits for Cd2+, Co2+, Ni2+, Pb2+, Zn2+, and Cu2+ ions were 0.01, 0.04, 0.01, 0.34, 0.05, and 0.04 μg L(-1), respectively. Relative standard deviation (RSD) values for 10 replicates at 100 μg L(-1) were lower than 6.0%. The proposed method could be successfully applied to the determination of Cd2+, Co2+, Ni2+, Pb2+, Zn2+, and Cu2+ ion in water samples.
authors.affiliation: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Zhao
authors.forename: Shuxian
authors.initials: S
authors.lastname: Zhong
authors.forename: Keming
authors.initials: K
authors.lastname: Fang
authors.forename: Zhaosheng
authors.initials: Z
authors.lastname: Qian
authors.forename: Jianrong
authors.initials: J
authors.lastname: Chen
mesh_terms: D019216:Metals, Heavy / Q000032:analysis*; D017830:Octoxynol; D015125:Oxyquinoline / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D019216:Metals, Heavy; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D011092:Polyethylene Glycols; D015125:Oxyquinoline; D017830:Octoxynol; C010615:Nonidet P-40