Investigation of Seawater Pretreatment Techniques for the Determination of Ultra-Trace Levels of ¹³⁵Cs

Abstract

Cesium-135 (¹³⁵Cs) is a radioactive nuclide released into the environment from nuclear tests and nuclear facilities. As an alternative to ¹³⁷Cs, it has potential applications as a tracer for oceanic circulation and for monitoring around nuclear-related sites, necessitating the development of reliable analytical methods. However, the typical concentration of ¹³⁵Cs in seawater is extremely low (estimated at 1.6 fg/kg), requiring separation and preconcentration from approximately 50 liters of seawater for mass spectrometric analysis. In this study, an insoluble cobalt ferrocyanide (Co-FC)-loaded adsorbent was synthesized via graft polymerization, and the adsorption and desorption conditions for Cs in seawater were investigated. In addition, a chemical separation method suitable for mass spectrometric determination was also examined.