Ultrafast and selective separation of 99mTc from molybdenum matrix using DBDGA deliberately tailored macrocyclic crown-ethers.

Abstract

Technetium-99m (99mTc) is an important medical radionuclide. Due to the crisis in supply of molybdenum-99 (99Mo), production of 99mTc directly via the 100Mo (p, 2n) reaction by cyclotron was proposed. In this process, the most critical challenge is to rapidly and efficiently separate 99mTc from high concentration of molybdenum. In this work, a novel ligand, bis(N,N-dibutyldiglycolamide)dibenzo-18-crown-6 (BisDBDGA-DB18C6) was successfully synthesized and used for extraction of TcO4- /ReO4- from molybdenum. The results demonstrated that BisDBDGA-DB18C6 expressed excellent selectivity for TcO4- with a high separation factor of 1.6×105 against Mo, a fast extraction kinetic (within 45s), and a high extraction capacity of 211mmol ReO4- (99TcO4-)/per mole of extractant. The extraction mechanism was proposed as a co-interaction of macrocyclic crown ether and N,N-dibutyldiglycolamide group through slope analysis, FT-IR, ESI-MS, 1H NMR titration and theory calculations. Importantly, 99Tc in the organic phase can be quantitatively (> 99%) and easily back-extracted using deionized water, which can be directly used for medical applications.