Chromatographic separation of the theranostic radionuclide 111Ag from a proton irradiated thorium matrix

Abstract: Column chromatographic methods have been developed to separate no-carrier-added ¹¹¹Ag from proton irradiated thorium targets and associated fission products as an ancillary process to an existing ²²⁵Ac separation design. Herein we report the separation of ¹¹¹Ag both prior and subsequent to ²²⁵Ac recovery using CL resin, a solvent impregnated resin (SIR) that carries an organic solution of alkyl phosphine sulfides (R₃P = S) and alkyl phosphine oxides (R₃P = O). The recovery yield of ¹¹¹Ag was 93 ± 9% with a radiochemical purity of 99.9% (prior) and 87 ± 9% with a radiochemical purity of 99.9% (subsequent to) ²²⁵Ac recovery. Both processes were successfully performed with insignificant impacts on ²²⁵Ac yields or quality. Measured equilibrium distribution coefficients for silver and ruthenium (a residual contaminant) on CL resin in hydrochloric and nitric acid media are reported, to the best of our knowledge, for the first time. Additionally, measured cross sections for the production of ¹¹¹Ag and ^110mAg for the ²³²Th(p,f)^110m,¹¹¹Ag reactions are reported within.