grazing incidence XRF is a  nondestructive new method with high sensitivity in the near surface area. Small amounts of contaminations can be detected easily and quantified. For the quantification knowledge abou the layer structure of the sample are requested, a theoretical calculation with respect to the sample structure. For the measurement the angle of incidence of the exciting radiation is changed and the fluorescence intensity of the element of interest collected.the measured curves are compared with the calculated ones, leading to the thickness and composition of the layer after variation. A concentration profile and thickness of near surface layers can be determined. As the results of fitting are not ambigous, additional information is requested. As complementary method X-ray reflectometry will be used.