Determination of Trace Neptunium and Plutonium by ICP-MS

A single TOA extraction chromatographic column with a twostage sample loading was used to separate Np and Pu from the environmental samples. Preliminary studies were performed to determine both Np and Pu by ICP-MS in one run. The ²³⁹Pu recovery of （92.7±3.1）％ and ²³⁷Np recovery of （96.8±2.7）％ in environmental samples were obtained. By spiking with ²⁴²Pu, isotope dilution ICP-MS was applied to measure ²³⁹Pu and ²⁴⁰Pu. The feasibility for the determination of both Pu and Np was proved by analyzing IAEA-135 reference samples. The measured values for Pu are in good agreement with recommended reference value (no Np standard value available).