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 990‰ silver are determined with ICP-OES following the bracketing method (ISO NP 19919, DIN 32562). For high-purity silver the determination of the precious metal content is performed with a different method. Here the impurities are analyzed, and the purity of the precious metal is calculated by 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 — high linear dynamic range and high sensitivity — it is the recommended analytical procedure for the analysis of contamination traces in high-purity silver. The application is described in the ISO standard 15096 as well as in the ASTM method B 413-97a. This report describes the methodology for the analysis of trace elements in high purity silver. It presents typical detection limits for selected elements as well as studies on accuracy.
Learn more in this informative report.