Preparation of Pharmaceutical-Grade Yttrium-90 Using Hold-back Carrier Method Coupled with Electrochemical Method

To address the technical challenge that traditional electrochemical methods face in balancing high ⁹⁰Y recovery with low ⁹⁰Sr residue during the separation of ⁹⁰Sr/⁹⁰Y, this study proposes for the first time the combination of the hold-back carrier method with electrochemistry. By introducing non-radioactive Sr as a hold-back carrier, the ⁹⁰Sr content in ⁹⁰Y was reduced to below 1×10⁻⁶ Bq ⁹⁰Sr/Bq ⁹⁰Y, while maintaining a ⁹⁰Y recovery rate of over 80%. The effects of electrolyte pH, electrolysis voltage, electrolysis time, and the hold-back carrier Sr on the recovery of ⁹⁰Y and the residue of ⁹⁰Sr were systematically investigated. It is confirmed that the electrolysis voltage is the key factor affecting ⁹⁰Y recovery, and the addition of hold-back carrier Sr can lower the ⁹⁰Sr residue by more than one order of magnitude. Under optimized conditions (electrolyte pH=3, electrolysis voltage of 4 V, single-cycle electrolysis duration of 1 h), after two electrolysis cycles with the hold-back carrier Sr introduced in the second cycle, 810 mCi of ⁹⁰Y is obtained from 1 Ci of ⁹⁰Sr/⁹⁰Y feed material, achieving a ⁹⁰Y recovery yield of 81% and a ⁹⁰Sr content in ⁹⁰Y was 3.1×10⁻⁷ Bq ⁹⁰Sr/Bq ⁹⁰Y. The ⁹⁰Y product meets pharmaceutical-grade requirements in terms of radionuclide purity, radiochemical purity, and chemical impurities.