Uncertainty evaluation of strontium-90 analysis in biological samples

In order to completely express the results of Sr-90 analysis, this paper presents the uncertainty evaluation of Sr-90 analysis in biological samples. Determination of Sr-90 in tea ash was taken as an example, the origins of uncertainty were discussed in detail and the mathematical model was established. Uncertainty components, standard uncertainty and expanded uncertainty were respectively calculated as well. Contributions of uncertainty components were also compared. The results showed that the radioactivity of Sr-90 in the tea ash was (68.8±2.6) Bq/kg (k = 2), and the uncertainty mainly originated from Y-90 beta-counting, detection efficiency of equipment and chemical recovery of the method. (authors)