Determination of gold in phosphates by activation analysis using epithermal neutrons

A simple method is described for determining gold in phosphates and phosphatic materials. Samples in a cadmium container are irradiated with epithermal neutrons to minimize the formation of 32 P, while permitting the formation of adequate amounts of 198 Au.  Fire assay-radiochemical methods are used to separate the 198 Au.  Concentrations as low as 0.1 ppb can be determined readily while maintaining low radiation levels.