Recovery of ²⁰¹Tl by ion exchange chromatography from proton bombarded thallium cyclotron targets

Abstract

Thallium-201 / Ion exchange chromatograpic separation / Thick Tl targetsSummary. A method based on ion exchange chromatography is presented for the recovery of 201 Tl and its precursor 201 Pb from proton bombarded natural thallium cyclotron targets. After bombardment the target is dissolved in diluted nitric acid. Water, hydrazine and ammonium acetate are added to the solution and the lead radioisotopes separated from the thallium by cation exchange chromatography on a Bio-Rex 70 column. The sorbed lead radioisotopes are eluted with dilute nitric acid and the separation repeated on a second Bio-Rex 70 column. After elution of the remaining thallium the column is left for 32 hours and the 201 Tl formed by decay of 201 Pb is eluted with an ammonium acetate solution. The 201 Tl eluate is acidified with a HNO 3 ϪHBrϪBr 2 mixture and the resulting solution is passed through an AG MP-1 anion exchanger column to remove any remaining lead isotopes. The 201 Tl is eluted with a hydrazine solution, the eluate evaporated to dryness and the 201 Tl finally dissolved in an appropiate solution to produce a 201 TlCl solution suitable for medical use. A high quality 201 Tl product is obtained containing Յ 0.1 µg of Tl/mCi (37 MBq) 201 Tl. The radionuclidic impurities are less than the maximum values specified by the US Pharmacopoeia and the British Pharmacopoeia.

Thallium Transfer from Hydrochloric Acid Media into Pure Ionic Liquids

“…In order to back-extract Tl in the case of very high D Tl(III) values (i.e., from [C 8 mim]­[Tf 2 N] ionic liquid phases after extraction), its reduction to the +1 oxidation state can be an alternative technique, because stripping with even highly concentrated aqueous HCl solutions will not allow one to reach distribution ratio values below 10. For example, a previous publication successfully applied hydrazine to reduce the thallium oxidation state.…”

Untitled

“…201 Tl results from the decay of 201 Pb which can be made by the irradiation of natural thallium . Two new methods have been reported 42,43 for the efficient separation of lead from thallium, in one 43 the 201 Pb remains adsorbed on the Bio-Rex 70 column whilst the unchanged thallium is removed. After about 30 hours the daughter 201 Tl can be eluted.…”