Automated extraction chromatographic separations of actinides using separation-optimized sequential injection techniques

A sequential injection (SI) separation system has been developed for automa ted analytical separations of actinides using an actinide specific extracti on chromatographic material (TRU-resin, Eichrom Industries, Inc., USA). On- line liquid scintillation counting was used to observe eluting species duri ng method development, and fraction collection and alpha energy analysis we re used for quantification. Several procedures for individual and group act inide elution are demonstrated and discussed, including elution of actinide s as a single group; elution as groups based on valence state; selective se paration of Pu using on-column redox chemistry; selective separation of Th; and various sequential actinide elution schemes. Eluent solution compositi ons and reagent chemistries were investigated with regard to elution peak s hapes, selectivity, recoveries, carryover, and suitability for rapid automa ted procedures. The SI separation methods described serve as the basis for an automated actinide separation work station. An automated actinide separa tion procedure has been applied towards the analysis of Am, Cm, and Pu isot opes in three types of aged nuclear waste samples. Results from automated a nalytical separations followed by quantification by alpha spectroscopy were in good agreement with results obtained using manual separation techniques .