The penetration depth for some elements is very small, so that one can speak of a surface analysis. If, as shown in Figure 36, the XRF instrument is used for quantitative analysis, then it is important that the analyzed sample represents the original sample.
During the first step of sample taking, it is important to be sure that one or more average samples are taken. With precise sample division, it is possible to reduce the amount of material. In the second step, the samples are ground, mixed and homogenized. In the third step, at least two samples are prepared from the homogeneous sample material and analyzed with the XRF instrument.