title: Optimization of dispersive liquid-liquid microextraction of copper (II) by atomic absorption spectrometry as its oxinate chelate: application to determination of copper in different water samples.
abstract: In this study a dispersive liquid-liquid microextraction (DLLME) method based on the dispersion of an extraction solvent into aqueous phase in the presence of a dispersive solvent was investigated for the preconcentration of Cu(2+) ions. 8-Hydroxy quinoline was used as a chelating agent prior to extraction. Flame atomic absorption spectrometry using an acetylene-air flame was used for quantitation of the analyte after preconcentration. The effect of various experimental parameters on the extraction was investigated using two optimization methods, one variable at a time and central composite design. The experimental design was performed at five levels of the operating parameters. Nearly the same results for optimization were obtained using both methods: sample size 5 mL; volume of dispersive solvent 1.5 mL; dispersive solvent methanol; extracting solvent chloroform; extracting solvent volume 250 microL; 8-hydroxy quinoline concentration and salt amount do not affect significantly the extraction. Under the optimum conditions the calibration graph was linear over the range 50-2000 muicro L(-1). The relative standard deviation was 5.1% for six repeated determinations at a concentration of 500 microg L(-1). The limit of detection (S/N=3) was 3 microg L(-1).
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, Tabriz University, Tabriz, Iran. farajzade@yahoo.com
authors.forename: Mir Ali
authors.initials: MA
authors.lastname: Farajzadeh
authors.forename: Morteza
authors.initials: M
authors.lastname: Bahram
authors.forename: Behzad Ghorbani
authors.initials: BG
authors.lastname: Mehr
authors.forename: Jan Ake
authors.initials: JA
authors.lastname: Jönsson
mesh_terms: D003300:Copper / Q000032:analysis*; D007492:Iran; D008832:Microchemistry / Q000379:methods*; D009942:Organometallic Compounds / Q000032:analysis* / Q000737:chemistry; D015125:Oxyquinoline / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis; D014881:Water Supply / Q000032:analysis*
chemical_list: D009942:Organometallic Compounds; D014874:Water Pollutants, Chemical; C047488:bis(8-quinolinolato)copper(II); D015125:Oxyquinoline; D003300:Copper