Determination of 99Tc in solid environmental samples by combining alkali fusion and rapid separation using TRans Uranium elements resin in alkali medium to triple quadrupole inductively coupled plasma mass spectrometry

Determination of 99Tc in various environmental samples is important not only for radioactive assessment but also for geochemical studies. In this work, we aim to develop a method for the monitoring of 99Tc in solid environmental samples. Alkali fusion instead of acid digestion was used for the dissolution of Tc from the sample. Therefore, the loss of Tc during sample preparation was negligible. The adsorption behavior of Re (as an analog of Tc) on the TRans Uranium elements (TRU) resin was investigated. Based on the results, for the first time, a simple separation method for Tc was established by using TRU resin in alkaline solution. Water was used for the elution of Tc from the resin column and the eluent could be directly injected to triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) for Tc measurement. The chemical recoveries for solid environmental samples (< 1 g) were beyond 85% and the whole analytical procedure could be finished within 3.5 h. High decontamination factors were obtained for the interfering elements. Mo isobaric interference was further removed by the introduction of O2 into the instrument as reaction gas. The detection limit of 99Tc was calculated to be 0.04 pg g-1 (for 1 g solid sample). Th developed method was suitable for the rapid monitoring of 99Tc in solid environmental samples for emergency response. Geological samples were used for method validation and the method was finally used for the determination of 99Tc in real radioactive contaminated samples.

Automated summary

This study developed a method for monitoring 99Tc in solid environmental samples. The use of alkali fusion instead of acid digestion ensured minimal loss of Tc during sample preparation. A simple separation method using TRU resin in alkaline solution was established, and water was used for elution and direct measurement of Tc. The method achieved high chemical recoveries and demonstrated fast and efficient analysis.