Speaker
Nicolas Guérin
(Canadian Nuclear Laboratories)
Description
Technetium-99 (⁹⁹Tc) is one of the most important fission products of ²³⁵U (~6% yield). It is a long lived radioisotope (2.11X10⁵ years half-life), which decays by emiting beta radiation. ⁹⁹Tc is of environmental concern because it is very mobile in the environment as Tc(VII) (TcO₄⁻) and can be bio-accumulated in some plants and animals. ⁹⁹Tc can be measured by ICP-MS, but ruthenium (Ru) (⁹⁹Ru⁺) and molybdenum (Mo) (⁹⁸Mo¹H⁺) interfere and have to be chemically removed. ⁹⁹Tc is frequently purified from these interferents using an anion exchange or TEVA® resin. The main issue regarding these resins is that ⁹⁹Tc is eluted with a high acid concentration solution, which cannot be directly introduced into an ICP-MS without causing corrosion issues. The acid solution has to be evaporated, but Tc(VII) is partially volatile in acidic solutions. Also, there is no adequate long-lived Tc isotope that could be used as a tracer to correct the recovery losses.
We have demonstrated that ⁹⁹Tc can be rapidly and selectively extracted on a TRU resin. It can be easily eluted from the resin using near boiling water, a solvent compatible with ICP-MS instrument. Rhenium (VII) (Re) has a similar chemical behavior to Tc(VII) on the resin in some conditions and can be used as a recovery tracer. Ru and Mo interferents can be removed effectively. A method was developed to determine ⁹⁹Tc in environmental waters. ⁹⁹Tc was pre-concentrated from a 1 L water sample using an anion exchange resin and then purified with a TRU® resin. There was no heating step for this method.
Author
Nicolas Guérin
(Canadian Nuclear Laboratories)
Co-authors
Jack Cornett
(University of Ottawa)
Nimal De Silva
(University of Ottawa)
Remi Riopel
(Canadian Nuclear Laboratories)
Sheila Kramer-Tremblay
(Canadian Nuclear Laboratories)
Xiongxin Dai
(China Institute for Radiation Protection)
