Supported ionic liquid phases for the separation of samarium and europium in nitrate media: Towards purification of medical samarium-153

Samarium-153 is a medical radionuclide that serves in nuclear medicine for bone pain palliation or imaging of the skeleton, and is produced in a nuclear research reactor by irradiation of an enriched samarium-152 target with a high flux of thermal neutrons. However, long-lived europium-154 impurities are formed concurrently, which restricts the use of the samarium-153 radiopharmaceutical. Previous research already showed the possibility to separate samarium and europium efficiently by solvent extraction with the undiluted ionic liquid [A336][NO3]. Current research efforts investigated the feasibility to convert the separation method to an extraction chromatography application, taking advantage of solid phase extraction techniques. TEVA particles, where the ionic liquid is immobilized onto a solid support, served as the stationary phase in the column. Eu(III) was reduced to Eu(II) in a concentrated nitrate salt solution prior to the separation step. After loading onto the extraction chromatography column, Eu(II) was not retained by the TEVA particles upon elution with a concentrated nitrate salt solution, whereas Sm(III) was extracted to the ionic liquid layer. Sm(III) could be efficiently removed from the column by elution with water, hence yielding a simple, yet efficient separation method.