Development of HCl-free solid-phase extraction combined with ICP-MS/MS for rapid assessment of difficult-to-measure radionuclides, 3; Measurement of Se concentration in concrete rubble

Banjarnahor, I. M. ; Do, V.-K.  ; Furuse, Takahiro; Ota, Yuki; Tanaka, Kosuke  

Se has been conventionally measured via radiometry. However, measuring Se this way is difficult due to its low specific radioactivity. Moreover, the measurement is time-consuming and susceptible to the radioactive interferences from highly radioactive nuclides (Sr, Cs, etc.) coexisting in the samples. ICP-MS/MS is widely known as a powerful technique to quantify difficult-to-measure radionuclides, which can effectively eliminate the interferences using a collision/reaction cell. In this research, a novel HCl-free chemical separation method was developed for separating Se from concrete matrices, followed by the selective measurement of Se concentration via ICP-MS/MS. Se was purified by stepwise chemical separation using anion exchange resin and activated alumina. The separation condition was optimized and evaluated. The chemical recovery of 85% was achieved. Se concentration was determined via ICP-MS/MS at m/z = 79 using ammonia gas as the reaction gas, and possible interferences such as those from the Br isobar and argon gas were effectively mitigated. A method limit of detection of 0.1 Bq g was achieved for the concrete rubble samples, making it a reliable tool for determining Se concentrations in concrete rubble collected from the Fukushima Daiichi Nuclear Power Station.