Rapid EElution of ²²⁶Th from a Two-Column ²³⁰U/²²⁶Th Generator with Diluted and Buffer Solutions

Abstract

A unique two-column 230U/226Th generator has been developed. The focus was hold on obtaining 226Th of high purity in a solution amenable to further labeling. The first column of the proposed generator filled with TEVA Resin held 230U, from which 226Th was eluted with 7 M HCl solution. UTEVA Resin pretreated with nitric acid solution was used as a sorbent for the second column for thorium retention. 226Th was extracted with 0.01-0.05 M citric buffer solution. One cycle of generator milking took 5-7 minutes and produced > 90% of 226Th in 1.5 ml of eluate, pH 4.5-5.0. The proposed two-column 230U/226Th generator was tested over two months including a second loading of 230U additionally accumulated from 230Pa. The 230U impurity in 226Th eluate was less than 0.01% allowing to use it directly in synthesis of radiopharmaceutical compounds.