The liquid sample measurements should be performed immediately after sample preparation to prevent source errors from liquid evaporation, sedimentation and leakage through sample cup. In some applications, it may be suggested to incorporate secondary cup systems into the XRF to prevent accidental spills from damaging the analyzer.
Solids and Powders
Solid samples, like rocks and soil, are not homogenous and require a more involved preparation in order to obtain the best data possible. Solid sample materials must first be ground and mixed into a powder and placed directly into a sample cup.
The precision and reproducibility of results from sample to sample may vary when simply measuring the grinded powder because the density may vary and finer grain will separate, causing layers to form and reducing the homogeneity of the sample. The best method is to press the powders into pellets using consistent pressure and dies.