The purity of precious metals is the main factor for their monetary value. Therefore, it needs to be most accurately determined when trading precious metals or precious metal products whereby contents of up to 99 % are determined with ICP-OES following the bracketing method (EN ISO 11494, 11495). For high-purity platinum the determination of the precious metal content is done with a different method. Here the impurities are analyzed, and the purity of the precious metal is calculated by a subtraction of the sum of all impurities in the sample from 1000 ‰.
Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) can be perfectly used for the analysis of impurities in precious metals. Due to its multi-element capability — large linear dynamic range and high sensitivity — it is the recommended analytical procedure for the analysis of contamination traces in high-purity platinum. The application is described in the ISO standard 15093 as well as in the ASTM standard B561-94. This report describes the methodology for the analysis of trace elements in precious metals. It presents typical detection limits for selected elements (as well as studies on accuracy).