A convenient spectrographic procedure for the determination of small amounts of palladium in Dore metal containing varying amounts of copper and gold is described. Copper in excess of 0.4% produced a marked enhancement of the palladium and silver line intensities, thereby prohibiting the use of a single working curve. A number of working curves were prepared, each corresponding to a definite copper concentration and, in the analysis of a Doré metal sample, the copper-silver intensity ratio served to indicate the position of the proper working curve. The influence of gold was significant only when its concentration exceeded 9% The procedure was employed to determine 45 to 800 ppm. of palladium in Doré metal and very much smaller concentrations of palladium (down to 0.05 ppm. in a 3 assay-ton sample) in ores, copper concentrates, blister copper and other metal-lurgical products.
Nicolas Tomingas and W. Charles Cooper, "Spectrographic Determination of Palladium in Dore Metal," Appl. Spectrosc. 11, 164-166 (1957)