Sequential determination of artificial radionuclides in atmospheric samples

A method has been developed for the sequential determination of 90Sr, 137Cs, and Pu-isotopes in atmospheric samples. The nitric acid extracted solution of atmospheric sample, containing cesium carrier, strontium carrier and Pu tracer, was neutralized to make iron hydroxide precipitate and carbonated precipitate by adding sodium hydroxide and sodium carbonate. 137Cs in the supernatant was preconcentrated in ammonium molybdophosphate (AMP), which was dissolved with sodium hydroxide solution and cesium in the AMP-dissolved solution was precipitated in cesium chloroplatinate. The precipitate was dissolved and passed through a column containing ammonium 12-molybdophosphate (AMP). Cesium was absorbed in AMP column together with natural rubidium. The AMP columns was eluted with 150 ml of 2 M ammonium nitrate solution to remove rubidium, and dissolved with 30% sodium hydroxide solution. After removing ammonia and molybdate, 1 ml of 10% hexachloroplatinic acid was added to the AMP-dissolved solution to make cesium chloroplatinate precipitate, 137Cs of which was measured with a low background gas-proportional α/β counter. The sensitivity of this method for 137Cs was much better than that of γ -spectrometry. The iron hydroxide and carbonate precipitate precipitates were used for Pu-isotopes determination with high-resolution ICP-MS and 90Sr determination, which was carried out by classical fuming nitric acid method and low background gas-proportional α/β counter as strontium carbonate precipitate