牛乳中の¹³¹Iの放射能濃度の測定に関する実験的検討

抄録

The analytical method combined with chemical treatment (ion exchange, solvent extraction, coprecipitation) and measurement of β radiation by a low back ground counter has been adopted in "Standard Method of Analysis for Hygienic Chemists" as the analytical method of ¹³¹I in milk. However, it was difficult to apply this method to the analysis of some kinds of milk on the market, because some colloidal phenomena appeared at the coprecipitation step. As a result of detection by use of thin layer chromatography and mass spectrometry, it is guessed that this is caused by materials possessing surface active action, such as fatty acids which constitute milk fat (e.g., palmitic acid, stearic acid etc.), and surface active agents added to dairy products. Therefore, after the removal with ether of these surfactants before the coprecipitation step, the measurement of radioactivities of ¹³¹I can be carried out without trouble.