Why interference tests?

In neutron activation analysis, correction for interference from other elements is usually carried out in the data processing; this is, however, only feasible when the radio-nuclides in question have at least one significant peak that is interference-free. Interference between nuclides with only one major photopeak and with comparable half-lives is best resolved by applying corrections based on experimentally determined values. In an extension of our previous method for the determination of As, Mn and Se to include Cu and Zn, interference from Cu in the determination of Zn is of this type. Furthermore, Cu interferes uot
only with the 69m Zn indicator used for determination of 65 Zn in the separated sample, but also with the Zn tracer added for chemical yield determination. Tests of the accuracy of the method were carried out by analysis of Standard Reference Materials 1571, Orchard Leaves, and 1577, Bovine Liver, from the National Bureau of Standards. For Orchard Leaves and for most biological materials, the interference from Cu was below the limit of detection for Zn; for Bovine Liver and other materials with unusual trace concentrations, correction was applied by means of an iterative procedure, Excellent agreement with certified values was
finally obtained for both materials.