Eliminating Mo isobaric interference using O2 as reaction gas for Tc measurement by triple quadrupole ICP-MS. Issue 6 (18th May 2022) - Bu, Wenting
Abstract : The introduction of O2 for the elimination of Mo interference for Tc measurement by ICP-MS/MS. Abstract : Monitoring of ultra-trace level 99 Tc in environmental samples is important for radioactivity assessment and tracing oceanographic processes. 97 Tc is an ideal yield tracer for the analysis of 99 Tc. However, when using 97 Tc as the tracer for 99 Tc measurement in environmental samples, complex and tedious chemical separation procedures were needed for the separation of isobaric interference of 97 Mo. In this work, for the first time, we reported a method for the measurement of Tc isotopes by triple quadrupole ICP-MS (ICP-MS/MS). An APEX-Ω high efficiency sample introduction system was used for the improvement of the instrument sensitivity. The absolute detection limit for 99 Tc was estimated to be 0.9 fg (0.6 mBq). We introduced O2 gas into the reaction cell of ICP-MS/MS. The majority of Mo + reacted with O2 to form MoO + and MoO2 + ions, which were eliminated by the second mass filter behind the reaction cell. A high separation factor (>1000) of Mo and Tc was found at an O2 flow rate of 70%. By using this method, the effect of trace amounts of Mo in the sample solution on the measurement of Tc could be negligible.