Substoichiometric determination of traces of gold by radioactive isotope-dilution analysis

A radioactive isotope-dilution method for the determination of traces of gold has been developed. It is based on the solvent extraction of gold diethyldithiocarbamate from 0-5N sulphuric acid containing ascorbic acid, by means of a substoichiometric amount of zinc diethyldithiocarbamate in chloroform. The separation has been applied to the analysis of gold-doped semiconductor-grade silicon and of gold-bearing ores. Amounts of gold down to 5 x 10(-7)g 20 ml of test solution can be determined.