Sequential extraction separation for determination of technetium-99 in radwastes by ICP-MS

An approach based on sequential extraction separation and the subsequent ICP-MS measurement was introduced to determine Tc-99 in radioactive wastes. The radwastes were firstly alkaline-fused and the Tc-99 was separated by a sequential solvent extraction prior to ICP-MS measurement. NaDDC was selected as a chelation reagent in the solvent extraction processes. The influence of HCl and matrix concentration on the recovery yield and the effectiveness of removing isobar and unwanted radionuclides, such as Cs-137, Mn-54, Co-60 and Ag-110m, were evaluated. The designed sequential extraction procedure was optimized by an extraction experiment. The proposed technique is proven to be a simple and practical alternative for Tc-99 determination in low-level radioactive wastes; chemical separation of Tc-99 can be simplified and preconcentration such as precipitation and/or ion exchange, before the solvent extraction, can be excluded.