title: A simple-rapid method to separate uranium, thorium, and protactinium for U-series age-dating of materials.
abstract: Uranium-series dating techniques require the isolation of radionuclides in high yields and in fractions free of impurities. Within this context, we describe a novel-rapid method for the separation and purification of U, Th, and Pa. The method takes advantage of differences in the chemistry of U, Th, and Pa, utilizing a commercially-available extraction chromatographic resin (TEVA) and standard reagents. The elution behavior of U, Th, and Pa were optimized using liquid scintillation counting techniques and fractional purity was evaluated by alpha-spectrometry. The overall method was further assessed by isotope dilution alpha-spectrometry for the preliminary age determination of an ancient carbonate sample obtained from the Lake Bonneville site in western Utah (United States). Preliminary evaluations of the method produced elemental purity of greater than 99.99% and radiochemical recoveries exceeding 90% for U and Th and 85% for Pa. Excellent purity and yields (76% for U, 96% for Th and 55% for Pa) were also obtained for the analysis of the carbonate samples and the preliminary Pa and Th ages of about 39,000 years before present are consistent with (14)C-derived age of the material.
authors.affiliation: Department of Chemistry, E373 CB, The University of Iowa, Iowa City, IA 52246, USA. Electronic address: andrew-knight@uiowa.edu.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Knight
authors.affiliation: Department of Chemistry, E373 CB, The University of Iowa, Iowa City, IA 52246, USA. Electronic address: eric-eithrheim@uiowa.edu.
authors.forename: Eric S
authors.initials: ES
authors.lastname: Eitrheim
authors.affiliation: Interdeciplinary Human Toxicology Program, E373 CB, The University of Iowa, IA 52246, USA. Electronic address: andrew-w-nelson@uiowa.edu.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Nelson
authors.affiliation: Department of Geological Sciences, Brigham Young University, S389 ESC, Provo, UT 84602, USA. Electronic address: oxygen.isotope@gmail.com.
authors.forename: Steven
authors.initials: S
authors.lastname: Nelson
authors.affiliation: Departments of Radiology and Radiation Oncology, Free Radical and Radiation Biology Program, Interdisciplinary Human Toxicology Program, The University of Iowa, ML B180 FRRB, 500 Newton Road, Iowa City, IA 52246, USA. Electronic address: michael-schultz@uiowa.edu.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Schultz
mesh_terms: D011478:Protactinium / Q000032:analysis* / Q000737:chemistry*; D013057:Spectrum Analysis; D013910:Thorium / Q000032:analysis* / Q000737:chemistry*; D014501:Uranium / Q000032:analysis* / Q000737:chemistry*
chemical_list: D011478:Protactinium; D014501:Uranium; D013910:Thorium
keywords: Age dating; Geochronology; Protactinium; Thorium; Uranium