title: A flow method based on solvent extraction coupled on-line to a reversed micellar mediated chemiluminescence detection for selective determination of gold(III) and gallium(III) in water and industrial samples.
abstract: A rapid and sensitive flow method, based on the combination of on-line solvent extraction with reversed micellar mediated chemiluminescence (CL) detection using rhodamine B (RB), was investigated for the selective determination of Au(III) and Ga(III) in aqueous solutions. 2.0 M HCl was the optimum for extracting Au(III) while a 5.0M HCl solution containing 2.5M LiCl was selected as an optimum acidic medium for extraction of Ga(III). The Au(III) and Ga(III) chloro-complex anions were extracted from the above aqueous acidic solutions into toluene as their ion-pair complexes with the protonated RBH(+) ion followed by membrane phase separation in a flow system. In a flow cell of a detector, the extract was mixed with the reversed micellar solution of cetyltrimethylammonium chloride (CTAC) in 1-hexanol-cyclohexane/water (1.0M HCl) containing 0.10 M cerium(IV) and 0.05 M lithium sulfate. Then uptake of the ion-pair by the CTAC reversed micelles and the subsequent CL oxidation of RB with Ce(IV) occurred easily and the CL signals produced were recorded. Using a flow injection system, a detection limit (DL) of 0.4 μM Au(III) and 0.6 μM Ga(III), and linear calibration graphs with dynamic ranges from the respective DLs to 10 μM for Au(III) and Ga(III) were obtained under the optimized experimental conditions. The relative standard deviations (n=6) obtained at 2.0 µM Au(III) and 4.0 µM Ga(III) were 3.0% and 2.4%, respectively. The presented CL methodology has been applied for the determination of Au(III) and Ga(III) in water and industrial samples with satisfactory results.
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan; Department of Chemistry, Faculty of Science, Minia University, El-Minia 61519, Egypt. Electronic address: tamerh76@yahoo.com.
authors.forename: Tamer H A
authors.initials: TH
authors.lastname: Hasanin
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Okamoto
authors.affiliation: Department of Chemistry, Graduate School of Science, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8526, Japan.
authors.forename: Terufumi
authors.initials: T
authors.lastname: Fujiwara
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods; D005708:Gallium / Q000032:analysis*; D006046:Gold / Q000032:analysis*; D007220:Industrial Waste / Q000032:analysis*; D008163:Luminescent Measurements / Q000379:methods*; D012997:Solvents / Q000032:analysis*; D014867:Water / Q000032:analysis*
chemical_list: D007220:Industrial Waste; D012997:Solvents; D014867:Water; D006046:Gold; D005708:Gallium
keywords: Chemiluminescence; Gallium(III); Gold(III); On-line solvent extraction; Reversed micellar system; Rhodamine B