A total burn spectrographic determination of silicon in plutonium

A total burn-spectrographic method has been applied to the determination of trace concentrations of silicon in plutonium. The sample is oxidized to plutonium dioxide, mixed with a germanium dioxide-graphite mixture containing tin internal standard, packed into cupped graphite electrodes, and burned to completion in a high amperage direct current arc. Plutonium spectral interference is minimized by optical means and by use of a less intense silicon line. The sensitivity is thereby decreased but is still sufficient to determine 25 ppm of silicon in plutonium. The precision of the method is estimated to be 8% (relative standard deviation) at the 270 ppm level and 14% at 40 ppm