Determinations of trace impurities in high purity gold plate were made by emission spectroscopy at concentration levels of 0.001 to 0.1%. Trace contaminants included Al, Cu, Si, Mg, Ni, Fe, Pb, and Ag. Contamination problems related to the handling of the gold plate were minimized by electrolytically depositing the gold on graphite electrodes followed by dissolution of the plate in a suitable solvent. Emission spectra were obtained on the resultant solution using high voltage ac arc excitation and vacuum cup electrodes.
Lester D. Shubin and Julian H. Chaudet, "Spectrographic Analysis of High Purity Gold Plate," Appl. Spectrosc. 18, 137-140 (1964)