Atomic fluorescence analysis of the substance
ATOMIC FLUORESCENCE ANALYSIS OF THE SUBSTANCE (EN: atomic-fluorescent material analysis; DE: atomare Fluoreszenzanalyse der Stoffe; FR: analyse de la matiere par fluorescence atomique; ES: análisis del material por fluorescencia atomica; RU: атомно-флуоресцентный анализ вещества) is the method of the quantitative elemental analysis with the help of the atomic spectra of the fluorescence.
There constitute the physical basis for the atomic fluorescence analysis two processes: the resonant absorption of the radiation from the external source, as the result of which the atoms transition into the excited state (see the "Atomic-absorption analysis" article), and the spontaneous transition of the excited atoms into the original energetical state, which is accompanied by the emission of the quanta of the light of the same frequency, as the radiation, which has been absorbed (their own glow, namely, the resonance fluorescence).
They usually cause the fluorescence of the sample, which is analyzed, with the help of the ultraviolet radiation from the mercury-quartz and xenon lamps or lasers. The glow is analyzed with the help of the spectrophotometer. The measure of the concentration of the element is the intensity of the fluorescence. They use for the calibration of the device the standard samples of the known chemical composition, which is corresponding to the composition of the sample. They use the atomic fluorescence analysis for the diagnosis of the minerals (scheelite, zircon, apatite, uranium salts, and others) within the mine workings, for the determination of the micro-impurities of the elements (Ag, Cd, Cu, Zn), for the flaw detection, and so on.
They determine with the help of the atomic fluorescence analysis approximately 50 elements within the various rocks, petroleum products, soils, and so on. The major advantages of this method are: the high sensitivity (10^-7%), great range of concentrations, at which the calibration graph is linear, that is the intensity of the emission of the fluorescent lines is proportional to the concentration of the impurity of that element, to which this line belongs (1-2 orders of magnitude of the values of concentration, up to 5 with the usage of the lasers); the possibility of the multi-element analysis.
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