@article {RADCHENKO2017318,
	title = {Radiometric evaluation of diglycolamide resins for the chromatographic separation of actinium from fission product lanthanides},
	journal = {Talanta},
	volume = {175},
	year = {2017},
	pages = {318 - 324},
	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 (ΔGaq) calculations confirm significantly higher selectivity of DGA based resins for LnIII over AcIII in the presence of nitrate. DFT calculations and experimental results reveal that Ac chemistry cannot be predicted from lanthanide behavior under comparable circumstances.},
	keywords = {Ac, Diglycolamide resins, Distribution coefficients, Extraction chromatography, Gibbs sorption energy, Lanthanide separation},
	issn = {0039-9140},
	doi = {https://doi.org/10.1016/j.talanta.2017.07.057},
	url = {http://www.sciencedirect.com/science/article/pii/S0039914017307798},
	author = {Valery Radchenko and Tara Mastren and Catherine A.L. Meyer and Alexander S. Ivanov and Vyacheslav S. Bryantsev and Roy Copping and David Denton and Jonathan W. Engle and Justin R. Griswold and Karen Murphy and Justin J. Wilson and Allison Owens and Lance Wyant and Eva R. Birnbaum and Jonathan Fitzsimmons and Dmitri Medvedev and Cathy S. Cutler and Leonard F. Mausner and Meiring F. Nortier and Kevin D. John and Saed Mirzadeh and Michael E. Fassbender}
}
@article {RADCHENKO201555,
	title = {Application of ion exchange and extraction chromatography to the separation of actinium from proton-irradiated thorium metal for analytical purposes},
	journal = {Journal of Chromatography A},
	volume = {1380},
	year = {2015},
	pages = {55 - 63},
	abstract = {Actinium-225 (t1/2=9.92d) is an α-emitting radionuclide with nuclear properties well-suited for use in targeted alpha therapy (TAT), a powerful treatment method for malignant tumors. Actinium-225 can also be utilized as a generator for 213Bi (t1/2 45.6min), which is another valuable candidate for TAT. Actinium-225 can be produced via proton irradiation of thorium metal; however, long-lived 227Ac (t1/2=21.8a, 99\% β-, 1\% α) is co-produced during this process and will impact the quality of the final product. Thus, accurate assays are needed to determine the 225Ac/227Ac ratio, which is dependent on beam energy, irradiation time and target design. Accurate actinium assays, in turn, require efficient separation of actinium isotopes from both the Th matrix and highly radioactive activation by-products, especially radiolanthanides formed from proton-induced fission. In this study, we introduce a novel, selective chromatographic technique for the recovery and purification of actinium isotopes from irradiated Th matrices. A two-step sequence of cation exchange and extraction chromatography was implemented. Radiolanthanides were quantitatively removed from Ac, and no non-Ac radionuclidic impurities were detected in the final Ac fraction. An 225Ac spike added prior to separation was recovered at >=98\%, and Ac decontamination from Th was found to be >=106. The purified actinium fraction allowed for highly accurate 227Ac determination at analytical scales, i.e., at 227Ac activities of 1{\textendash}100kBq (27nCi to 2.7μCi).},
	keywords = {Actinium isotopes, Extraction chromatography, Ion exchange, Lanthanide separation, Thorium chelation, Thorium metal},
	issn = {0021-9673},
	doi = {https://doi.org/10.1016/j.chroma.2014.12.045},
	url = {http://www.sciencedirect.com/science/article/pii/S0021967314019645},
	author = {V. Radchenko and J.W. Engle and J.J. Wilson and J.R. Maassen and F.M. Nortier and W.A. Taylor and E.R. Birnbaum and L.A. Hudston and K.D. John and M.E. Fassbender}
}
