Precise U and Pu Isotope Ratio Measurements in Nuclear Samples by Hyphenating Capillary Electrophoresis and MC-ICPMS.

Precise isotopic and elemental characterization of spent nuclear fuel is a major concern for the validation of the neutronic calculation codes and waste management strategy in the nuclear industry. Generally, the elements of interest, particularly U and Pu which are the two major elements present in spent fuel, are purified by ion exchange or extractant resins before off-line measurements by thermal ionization mass spectrometry. The aim of the present work was to develop a new analytical approach based on capillary electrophoresis (CE) hyphenated to a multicollector inductively coupled plasma mass spectrometer (MC-ICPMS) for online isotope ratio measurements.

Multi-elemental Nd, Sm, Eu, Gd isotope ratio measurements by stop-flow isotachophoresis coupled to MC-ICPMS.

In this study, a new analytical procedure based on isotachophoresis (ITP) coupled to a multi collector inductively coupled plasma mass spectrometer named Stop-Flow-ITP-MC-ICPMS is developed for exhaustive and high-precision multi-elemental isotopic characterization. We demonstrate that Stop-Flow-ITP makes it possible to stop the analytes migration several times for a duration compatible with the detector configuration changes without losing the separation performance. With this procedure, isotope ratio measurements of four lanthanides of interest for nuclear applications (Nd, Sm, Eu and Gd) were obtained with a reproducibility better than 0.