To distinguish the purity of gold is crucial in precious metals analysis. In particular the separation between 99.5 wt.% and 99.9 wt.% is important for different applications: the effort in refining gold to the higher purity is bigger although the material value is not that different. For economic reasons it can therefore be important to know which caratage is at hand.
The measurements with the M1 MISTRAL show that it is possible to distinguish between 99.5 wt.% and 99.9 wt.% Au. The peaks of traces can be easily detected and used for quantification. The measured samples have concentrations of approx. 0.5 wt.% and 0.1 wt.% Ag, respectively. Other trace elements (for example Cu, Ni, Zn, Pd) have even a better limit of detection due to their higher excitation efficiency.
The example shows, that it is possible to identify and quantify elements with a concentration lower than 0.04 % to 0.01 %. The intensity and the peak-to-background ratio of these peaks are large enough to detect with the M1 MISTRAL.