Radiometric evaluation of diglycolamide resins for the chromatographic separation of actinium from fission product lanthanides

Valery Radchenko; Tara Mastren; Catherine A L Meyer; Alexander S Ivanov; Vyacheslav S Bryantsev; Roy Copping; David Denton; Jonathan W Engle; Justin R Griswold; Karen Murphy; Justin J Wilson; Allison Owens; Lance Wyant; Eva R Birnbaum; Jonathan Fitzsimmons; Dmitri Medvedev; Cathy S Cutler; Leonard F Mausner; Meiring F Nortier; Kevin D John; Saed Mirzadeh; Michael E Fassbender

doi:10.1016/j.talanta.2017.07.057

Radiometric evaluation of diglycolamide resins for the chromatographic separation of actinium from fission product lanthanides

Talanta. 2017 Dec 1:175:318-324. doi: 10.1016/j.talanta.2017.07.057. Epub 2017 Jul 20.

Authors

Valery Radchenko¹, Tara Mastren², Catherine A L Meyer², Alexander S Ivanov³, Vyacheslav S Bryantsev³, Roy Copping⁴, David Denton⁴, Jonathan W Engle⁵, Justin R Griswold⁴, Karen Murphy⁴, Justin J Wilson⁶, Allison Owens⁴, Lance Wyant³, Eva R Birnbaum², Jonathan Fitzsimmons⁷, Dmitri Medvedev⁷, Cathy S Cutler⁷, Leonard F Mausner⁷, Meiring F Nortier², Kevin D John², Saed Mirzadeh⁴, Michael E Fassbender⁸

Affiliations

¹ Chemistry Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA; Life Science Division, TRIUMF, 4004 Wesbrook Mall, Vancouver, BC V6T 2A3, Canada.
² Chemistry Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA.
³ Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
⁴ Nuclear Security and Isotope Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
⁵ Chemistry Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA; Department of Medical Physics, University of Wisconsin, Madison, WI 53705, USA.
⁶ Chemistry Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA; Department of Chemistry&Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
⁷ Collider-Accelerator Department, Brookhaven National Laboratory, Bldg 801, Upton, NY 11973, USA.
⁸ Chemistry Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA. Electronic address: [email protected].

PMID: 28841997
DOI: 10.1016/j.talanta.2017.07.057

Abstract

Actinium-225 is a potential Targeted Alpha Therapy (TAT) isotope. It can be generated with high energy (≥ 100MeV) proton irradiation of thorium targets. The main challenge in the chemical recovery of ²²⁵Ac lies in the separation from thorium and many fission by-products most importantly radiolanthanides. We recently developed a separation strategy based on a combination of cation exchange and extraction chromatography to isolate and purify ²²⁵Ac. In this study, actinium and lanthanide equilibrium distribution coefficients and column elution behavior for both TODGA (N,N,N',N'-tetra-n-octyldiglycolamide) and TEHDGA (N,N,N',N'-tetrakis-2-ethylhexyldiglycolamide) were determined. Density functional theory (DFT) calculations were performed and were in agreement with experimental observations providing the foundation for understanding of the selectivity for Ac and lanthanides on different DGA (diglycolamide) based resins. The results of Gibbs energy (ΔG_aq) calculations confirm significantly higher selectivity of DGA based resins for Ln^III over Ac^III in the presence of nitrate. DFT calculations and experimental results reveal that Ac chemistry cannot be predicted from lanthanide behavior under comparable circumstances.

Keywords: (225)Ac; Diglycolamide resins; Distribution coefficients; Extraction chromatography; Gibbs sorption energy; Lanthanide separation.