Simultaneous Determination Of Natural Uranium And Thorium In Food By Tri-n-octylamine Extraction-spectrophotometric Method

Objective This study aimed to establish a method which can determine the natural uranium and thorium in food simultaneously. Methods Based on the N-235 extraction-spectrophotometry and the chemical similarity of TOA and N235, necessary condition experiments were finished by substituting TOA for N235, the best conditions for the main analytical steps were obtained. By adopting these best conditions, methodological bases of the new analytical procedures were established. The new analytical method has been tested and verified. Results The lowest detectable limits of the method were 3.47x 10-8g Th/g ash and 9.47×10-8g U/g ash. The recovery of standard addition of Th and U are 98.7%and 96.7%respectively. The relative standard deviation of Th and U are±5.95%and±6.31%respectively. The uranium and thorium contents in main types of food ash samples were determined, the chemical recoveries were all between 70%and 90%. Conclusions The Tri-n-octylamine extraction spectrophotometric method of simultaneous determination for natural uranium, thorium in food was established for the first time. This method is simple, quick and has good accuracy and precision.