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

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• 作者：Jixin Qiao^a ; ^{jiqi@risoe.dtu.dk} ; ^{qiaojixin2004@gmail.com} ; Xiaolin Hou^a ; Per Roos^a ; Manuel Miró ; ^b
• 关键词：²³⁷Np ; ²⁴²Pu ; Non-isotopic tracer ; Rapid analysis ; Automatization ; Environmental samples ; Anion exchange chromatography ; Sequential injection ; ICP-MS
• 刊名：Talanta
• 出版年：2011
• 出版时间：15 April 2011
• 年：2011
• 卷：84
• 期：2
• 页码：494-500
• 全文大小：631 K

文摘

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-8 M 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 2.5 h, and leads to a significant decrease in labor intensity compared to conventional batch-wise protocols.