title: Determination of 232Th in seawater by ICP-MS after preconcentration and separation using a chelating resin.
abstract: This article describes an analytical method for the separation, preconcentration and determination of (232)Th in seawater samples at sub-ng/L levels using a NOBIAS CHELATE PA1 resin and a sector field (SF) inductively coupled plasma mass spectrometer (ICP-MS). The resin showed excellent adsorption of (232)Th at a low pH of 2.4 ± 0.4 in a relatively small volume (200 mL) of seawater. (232)Th adsorbed on the resin was easily eluted using 5 mL of 0.8M HNO(3). An enrichment factor of 40 was achieved for (232)Th analysis. Ethylenediamine-tetraacetic acid disodium salt dehydrate (EDTA) was used to investigate the effect of (232)Th-binding organic ligand on the retention of (232)Th on the chelating resin. Results obtained using acidified samples (pH of 2.4 ± 0.4) showed EDTA had no significant effect on (232)Th recovery, indicating that at this low pH, (232)Th was dissociated from the (232)Th-binding organic ligand and quantitatively retained on the NOBIAS CHELATE PA1 resin. The developed analytical method was characterized by a separation and preconcentration taking approximately 4h and a low detection limit of 0.0038 ng/L for (232)Th, and was successfully applied to the determination of (232)Th in seawater samples collected from coastal areas, Japan.
authors.affiliation: Office of Biospheric Assessment for Waste Disposal, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba 263-8555, Japan. takata@nirs.go.jp
authors.forename: Hyoe
authors.initials: H
authors.lastname: Takata
authors.forename: Jian
authors.initials: J
authors.lastname: Zheng
authors.forename: Keiko
authors.initials: K
authors.lastname: Tagami
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Aono
authors.forename: Shigeo
authors.initials: S
authors.lastname: Uchida
mesh_terms: D000327:Adsorption; D053000:Analytic Sample Preparation Methods / Q000379:methods*; D002614:Chelating Agents / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000379:methods*; D012117:Resins, Synthetic / Q000737:chemistry*; D012623:Seawater / Q000737:chemistry*; D013910:Thorium / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification*
chemical_list: D002614:Chelating Agents; D008024:Ligands; D012117:Resins, Synthetic; D013910:Thorium