Evaluation of a Wet Chemistry Method for Isolation of Cyclotron Produced [211At]Astatine

A “wet chemistry” approach for isolation of At from an irradiated bismuth target is described. The approach involves five steps: (1) dissolution of bismuth target in conc. HNO3; (2) removal of the HNO3 by distillation; (3) dissolution of residue in 8 M HCl; (4) extraction of At from 8 M HCl into DIPE; and (5) extraction of At from DIPE into NaOH. Results from 55 “optimized” At isolation runs gave recovery yields of approximately 78% after decay and attenuation corrections. An attenuation-corrected average of 26 ± 3 mCi in the target provided isolated (actual) yields of 16 ± 3 mCi of At. A sixth step, used for purification of At from trace metals, was evaluated in seven runs. In those runs, isolated At was distilled under reductive conditions to provide an average 71 ± 8% recovery. RadioHPLC analyses of the isolated At solutions, both initial and after distillation, were obtained to examine the At species present. The primary species of At present was astatide, but astatate and unidentified species were also observed. OPEN ACCESS Appl. Sci. 2013, 3 637 Studies to determine the effect of bismuth attenuation on At were conducted to estimate an attenuation factor (~1.33) for adjustment of At readings in the bismuth target.