Abstract
The present paper describes a simple determination procedure of 137Cs in a total diet (5-days sample) . Cesium carrier was added to the ashed sample. The sample was treated with hydrochloric acid. Calcium contained in the sample was separated as a carbonate precipitate. The filtrate was acidified with nitric acid. By adding phosphoric acid and ammonium molybdate to the solution, 137Cs was co-precipitated with phospho-ammonium molybdate. The amount of 137Cs in the precipitate was measured by 7-spectrometry. In the co-precipitation step, effects of factors such as temperature, amount of phosphoric acid and ammonium molybdate added, acidity of the solution, etc., were obseroed. Interference of potassium and ammonium was also measured. It was shown that potassium, ammonium, and phosphate contained in the diet do not interfere with the co-precipitation of 137Cs; contamination of the phospho-ammonium molybdate by co-existing 95Zr-95Nb and 106Ru-106Rh is small; and recovery of 137Cs by this procedure is nearly 100%.
