Studies on simultaneous separation and determination of lanthanides and actinides by ion chromatography inductively coupled plasma mass spectrometry combined with isotope dilution mass spectrometry

Abstract

A procedure for the simultaneous separation and determination of fission products (lanthanides) and actinides (Pu, Np, U, Am and Cm) is described. The method is based on the use of an anionic/cationic mixed bed chromatographic column (CS5A, Dionex), coupled on-line to an ICP-MS detector. Optimisation of the parameters was carried out with standard solutions containing actinides and lanthanides at the 50 ng ml⁻¹ concentration level. The effects of different oxidising/reducing agents as well as different mobile phases on the intensity and position of the chromatographic peaks were investigated. The analytical procedure was validated by the use of certified materials as well as by other independent techniques. Analytical figures of merit resulting from the procedure were compared with those obtained using other commercially available ion-exchange stationary phases. The procedure developed was applied to the inventory of spent nuclear fuel samples. Detection limits of 0.25 ng ml⁻¹ and 0.45 ng ml⁻¹ were obtained for lanthanides and actinides, respectively. Analytical precision was typical better than 5% over seven repeated measurements.