Reliable determination of 237Np in environmental solid samples using 242Pu as a potential tracer

Jixin Qiao, Xiaolin Hou, Per Roos, Manuel Miró

    Research output: Contribution to journalJournal articleResearchpeer-review


    This paper reports an analytical method for rapid determination of neptunium (237Np) in environmental solid samples exploiting automated sequential injection (SI)-based anion exchange separation. Pivotal issues on analytical method performance were investigated including sorption behavior of 237Np onto various AG 1-type anion exchangers; suitability of 242Pu as a tracer for 237Np determination in environmental solid samples; and long-term chemical stability of tetravalent Np. Experimental results revealed that the degree of resin cross-linking has a significant influence on the separation efficiency in terms of chemical yields of 237Np and removal of interfering nuclides. Although ca. 30% of sorbed Np onto AG 1-×4 was stripped out during HCl rinsing step for the removal of Th, chemical yield ratios of 237Np to 242Pu were proven steady with an average value of 0.67±0.04 (n=15) under selected experimental conditions. Disulfite-8M HNO3 was selected as a redox pair for valence adjustment to Np(IV) and the tetravalent Np in the sample solution was demonstrated to be stabilized for up to 5 days under 3°C. The analytical results for reference materials showed a good agreement with the expected values, thereby demonstrating the usefulness of 242Pu as a non-isotopic tracer for 237Np chemical yield monitoring. The on-column separation procedure fosters rapid analysis as required in emergency situations since each individual sample can be handled within 2.5h, and leads to a significant decrease in labor intensity compared to conventional batch-wise protocols.
    Original languageEnglish
    Issue number2
    Pages (from-to)494-500
    Publication statusPublished - 2011


    • Radio ecology and tracers


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