ICP-MS測定のため大量の環境試料を用いるTc-99の分析法

Abstract

Sample preparation for measurement of Tc-99 in a large amount of soil and water samples by ICP-MS has been developed using Tc-95m as a yield tracer. This method is based on the conventional method for a small amount of soil samples using incineration, acid digestion, extraction chromatography (TEVA resin) and ICP-MS measurement. Preliminary concentration of Tc has been introduced by co-precipitation with ferric oxide. The matrix materials in a large amount of samples were more sufficiently removed with keeping the high recovery of Tc than previous method. The recovery of Tc was 70-80 percent for 100 g soil samples and 60-70 percent for 500 g of soil and 500 L of water samples. The detection limit of this method was evaluated as 0.054 mBq/kg in 500 g soil and 0.032 microBq/L in 500 L water. The determined value of Tc-99 in the IAEA-375 (soil sample collected near the Chernobyl Nuclear Reactor) was 0.25 +/- 0.02 Bq/kg.