X-ray fluorescence spectrometry has been used in a broad spectrum of applications. These include elemental analysis, both qualitative and quantitative, based on wavelength dispersive (WDXRF) or energy dispersive (EDXRF) methods. In these methods the detection limit of analyte elements is mainly in the one to ten ppm range in solid samples. Therefore, improvement of these limits is desirable for many useful applications. In this context it is essential to remember that the excitation efficiency for fluorescent X-rays is very low when compared with electron or proton excitation. In the case of WDXRF, the dominant factor is the low reflectivity from the analyzing crystal.