title: Determination of uranium in seawater by flow-injection preconcentration on dodecylamidoxime-impregnated resin and spectrophotometric detection.
abstract: A flow injection method has been developed for the determination of uranium in seawater combining the on-line preconcentration with spectrophotometric detection. An aliquot (10 mL) of the seawater sample adjusted to pH 5.5 was injected into the analytical system and uranium was adsorbed on the column packed with styrene-divinylbenzene copolymer resin (Bio-Beads SM-2) modified with dodecylamidoxime which showed high selectivity to uranium. Uranium was then eluted with 0.01 M hydrochloric acid and detected spectrophotometrically after the reaction with Chlorophosphonazo III. Interference from calcium and strontium was masked with cyclohexanediaminetetraacetic acid added to the chromogenic reagent solution. The sample throughput, the detection limit (3σ), and the preconcentration factor were 23 per hour, 0.13 μg/L, and 20, respectively, when the sample injection volume was kept at 10 mL. The precision at the 2 μg/L level was less than 4% (RSD). The proposed method was applied to the determination of uranium in the seawater samples collected off the Boso peninsula, Japan and the uranium concentration was found to be ca. 3 μg/L, which is close to the literature data. The yield of the recovery test ranged from 95% to 99%.
authors.affiliation: Department of Applied Chemistry and Bio-technology, Graduate School of Engineering, Chiba-University, Yayoi-cho, Inage-ku, Chiba 263-8522, Japan. koguma@faculty.chiba-u.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Oguma
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Kyoichi
authors.initials: K
authors.lastname: Saito
mesh_terms: D000327:Adsorption; D053000:Analytic Sample Preparation Methods / Q000379:methods*; D002614:Chelating Agents / Q000737:chemistry; D017022:Flow Injection Analysis / Q000379:methods*; D007267:Injections; D008670:Metals / Q000737:chemistry; D010091:Oximes / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry*; D012623:Seawater / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D014501:Uranium / Q000032:analysis* / Q000737:chemistry*
chemical_list: D002614:Chelating Agents; D008670:Metals; D010091:Oximes; D011137:Polystyrenes; D012117:Resins, Synthetic; C432006:divinylbenzene-polystyrene copolymer; C561279:dodecylamidoxime; D014501:Uranium