Given the low levels of 99Tc (long half-lived artificial radionuclide) in the environnement (10^-8 M to 10^-12 M), its determination currently necessitates an enrichment and separation from the sample matrix prior to instrumental measurement. Therefore, nuclear safety monitoring requires the knowledge of the redox and chemical properties of this element in order to predict its behaviour and transfer in the environment. So, a separative and very sensitive measurement technique must thus be employed.

We have developed a new environmental measurement method applied to the quantification
and speciation of 99Tc in sample at environmental concentrations. Indeed, we have combined a Capillary Electrophoresis (CE) with an Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The limit of detection of 99Tc is about 2.10^-8 M by CE/ICP-MS system equipped with a PFA-50 nebuliser.

In addition to the detection and measurement of technetium, we can separate online 99Tc(VII)
of its intefering radionuclides like molybdenium and ruthenium by CE/ICP-MS. Indeed, due do the different migration time of each anions, it’s possible to determinate a signal at m/z= 99 which is only given to 99Tc. Results obtained by this method have been compared to an usual radiochemical technique, extraction of Tc(VII) by a TEVA resin followed by ICP-MS measurement.

Within the framework of storage of spent fuel, studies on the speciation of Tc(VII) by CE / ICP-MS iron-sulphide soils in anoxidic conditions have shown that technetium VII is reduced by sulphured suspensions