Energy-Dispersive, X-Ray Fluorescence Analysis

Energy-dispersive X-ray fluorescence (EDXRF) is an analytical method for qualitative, as well as quantitative, determination of elements in a sample, independent of their chemical form. It is built on the fact that elements that are irradiated with high-energy X-rays have a certain probability of emitting characteristic X-rays, the energies of which are unique for each element. In the energy-dispersive (ED) systems, the emitted X-rays are collected, by discriminating them on the basis of their energies. The use of the EDXRF technique has accelerated since the 1960s as a result of the development of liquid nitrogen-cooled solid-state detectors, nuclear electronics, and small computers. Nowadays, compact light-weight electrically cooled detectors are available, which, together with air-cooled low-power X-ray tubes, are perfectly suited for handheld spectrometers. EDXRF is multielemental and nondestructive and can be applied to large, as well as small, samples of different composition and character. If conditions are optimized, the minimum detection limits can be below the nanogram absolute or micrograms per gram concentration level for small laboratory instruments and into the femtogram or nanograms per milliliter region for more advanced instrumentation (total reflection X-ray fluorescence (TXRF) and synchrotron radiation).