Limit of the INAA procedure for copper determination based on the 64Cu 511 keV line

It has been demonstrated that the interferences on 64Cu 511 keV line from nuclides having high energy γ-rays can be effectively reduced physically. An INAA procedure is proposed and used to determine trace amounts of Cu in biological and environmental samples. However, due to the fact that the interferences on 64Cu 511 keV line are not completely eliminated, the question arises on what is the limit of the non-destructive method for Cu determination. An equation is derived to establish the relation between the minimum detectable Cu concentration and the INAA experimental conditions. Based on this equation, and optimised INAA procedure is worked out and applied to blood analysis. The results show that the optimised INAA procedure is able to determine Cu quantitatively for samples with Na-to-Cu content ratio less than 600-1000. (author)