Effect of drying temperature on the quantitative analysis of 131I in algal samples by γ-spectrometry.

ABSTRACT

131I has been extensively utilized in nuclear medicine, resulting in its widespread detection in coastal algal samples due to its discharge. Therefore, it is essential to monitor 131I in the coastal algal samples. γ-spectrometry is an expeditious method for measuring 131I, but this method requires the pretreatment of the algal sample. The effect on 131I in the algal sample during the oven-drying treatment is unclear. In this study, the Laminaria japonica Areschoug and Sargassum vachellianum Greville were collected at two locations and analyzed for 131I using γ-spectrometry. Additionally, the content of iodine was measured using an Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) to clarify the effect of 131I loss during drying treatment at different temperatures. The results demonstrated that the dried Laminaria and Sargassum samples had calculated 131I activity concentration relative standard deviations (RSDs) of 6.34 % and 16.31 %, respectively, while the fresh samples exhibited RSDs of 11.70 % and 15.57 %. Additionally, the iodine content RSDs in the dried samples were 9.19 % for Laminaria and 10.34 % for Sargassum. Significantly, discrepancies in 131I activity concentration between the fresh and dried Laminaria and Sargassum were 5.4 % and 10.3 %. These findings indicate that the temperature factor in drying has no effect on 131I loss in Laminaria and Sargassum in the range of 70 °C-110 °C.