Preparation and purification of high specific activity radionuclides for environmental studies

High sp. activity radionuclides are a powerful tool for labeling a large range of inorganic and organometallic species that are present in the environment at very low concentrations. To study the environmental impact of trace elements (TE) on humans, it is of fundamental importance to carry out both in-vitro and in-vivo experiments on cell cultures and lab. animals, with concentrations of these TE representative of the actual long-term and low-level exposures. To obtain these radiotracers in a very high specific activity form, it is necessary (1) to optimize the production method by either charged particle accelerator (normally cyclotron) or nuclear reactor irradiation; (2) to separate and purify them from the irradiated target by chemical or physicochemical methods, without the addition of inactive carriers (i.e., the socalled no-carrier-added form); and (3) to carry out a series of analytical and radioanalytical tests to verify the chemical, radiochememical and radionuclide purities of the tracer or labeled compound under investigation. Some production, separation, purification and quality control methods developed for the 2 cyclotron-produced radionuclides 52Mn and 48V are presented and discussed.