Investigation toward the quantitative analysis of ²³⁷Np in seawater

Abstract

To establish a mass spectrometric method for determining²³⁷Np in seawater water, we investigated (1) a preconcentration technique of Np from seawater using an amidoxime adsorbent, and (2) the construction of the excitation functions of Np isotope via the ²³²Th+⁷Li reaction for spike production. Under optimized conditions, approximately 90% of Np in seawater was adsorbed onto the amidoxime adsorbent, and about 80% of the adsorbed Np was successfully eluted by treating the ashed adsorbent with 3 M nitric acid. In the ²³²Th+⁷Li reaction, ^236gNp was successfully synthesized and its excitation function was obtained. It was also revealed that ²³⁷Np is concurrently produced in this reaction.