The monetary value of jewelry alloys is mainly determined by their content of precious metals. That is why elemental analysis of this kind of samples is of extreme importance. The high value of the samples, their intricate nature and the often inhomogeneous composition pose following requirements for the analytical method:
- High precision and accuracy
- Non-destructive analysis, if possible
- Small spot size for analysis of rough surfaces
- Determination of all components of the alloy, even unex-pected elements.
Several methods have been developed for the analysis of precious metal alloys. One of the standard techniques is fire assay, which offers extremely high precision and accuracy. However, this method has various disadvantages: it is destructive, time consuming and produces a high amount of toxic waste.
Conventional X-ray fluorescence (XRF) spectroscopy could be used for this analytical task, but the analyzed area would be too large - with diameters in the range of 10 to 60 mm. The development of micro-XRF methods, where small sample areas down to 0.1 mm can be analyzed, offers new possibilities for this application.