Spectrofluorimetric procedure using 2,3-napthalenediamine for determining selenium in rocks

A spectrofluorimetric procedure using 2,3-naphthalenediamine is given for determining submicrogram and microgram quantities of selenium in mineralized rocks. Conditions for the satisfactory isolation and concentration of the selenium are investigated and tested on six USGS standard rocks of various types. Selenium contents of samples treated by an alkaline sinter and leach are compared with those obtained by acid decomposition and with published values determined by neutron-activation analyses. In pure solutions, 0.01 μg of selenium can be determined with a relative standard deviation of 25 percent, thus setting the determination limit at approximately 0.01 ppm Se in a 1.0-g sample. When the amount of selenium is ≥0.1 ppm, a relative standard deviation of 10 percent or less is obtained.