A Chromatographic Method to Separate Sc(III) from Zn(II) Ions: A Step in the Purification of Sc-44 (an isotope of medical interest)

CERN MEDICIS produces radioactive isotopes by recovering the 1,4 GeV proton beam from ISOLDE before it reaches the beam dump using different types of targets behind the ISOLDE targets. In the end, the isotopes are implanted on a zinc- coated gold foil. Therefore, the radioisotope of interest needs to be separated from the zinc coating on which it is implanted. The goal of this project was to develop a ion-exchange chromatography method to separate scandium (III) ions from zinc (II) ions. Four different resins were tested as stationary phases and several concentrations of nitric acid were used as solvents, rinsing and eluting agents. Preliminary assays showed a >99% reduction in zinc concentration (from 348,7 ppm to 0,6 ppm) using 70 mg of the DGA resin while maintaining a concentration of ~5,0 ppm of scandium ions in the eluate according ICP-MS analysis. During the studentship, other short tasks were done. For example, basic laboratory equipment was procured for the lab, a literature review on 225Ra/225Ac purification was written and two scientific visits were completed: one to the Nuclear Medicine Service at CHUV Hospital (Lausanne) and one to the cyclotron facility at Bern University Hospital (Bern).