Highly Efficient Separation of Ultratrace Radioactive Copper Using a Flow Electrolysis Cell

Preparing compounds containing the radioisotope Cu-64 for use in positron emission tomography cancer diagnostics is an ongoing area of research. In this study, a highly efficient separation method to recover Cu-64 generated by irradiating the target Ni-64 with a proton beam was developed by employing a flow electrolysis cell (FE). This system consists of (1) applying a reduction potential for the selective adsorption of Cu-64 from the target solution when dissolved in HCl and (2) recovering the Cu-64 deposited onto the carbon working electrode by desorbing it from the FE during elution with 10 mmol/L HNO3, which applies an oxidation potential. The Cu-64 was selectively eluted at approximately 30 min under a flow rate of 0.5 mL/min from the injection to recovery. The newly developed flow electrolysis system can separate the femtomolar level of ultratrace radioisotopes from the larger amount of target metals as an alternative to conventional column chromatography.