X-ray fluorescence spectrometry or XRF is a branch of analytical chemistry and spectroscopy. This instrumental analysis technique provides information about which elements are present in a sample (qualitative analysis) and the amount or concentration of those elements (quantitative analysis). An impressively wide assortment of materials can be characterized using XRF in physical forms such as solids, liquids, powders, pastes, films, fibers, and filter papers. The metallurgical, mining, cement, petroleum, catalyst, ceramics, glass, semiconductor, polymer, and coating industries are among the many that rely on XRF for materials testing purposes ranging from in-line or near-line process control to product development, failure analysis, and sophisticated R&D applications.

In addition to its flexibility in accommodating a diverse range of material types, the popularity of the XRF technique also stems from factors such as:

  • the relative ease and speed of sample preparation compared to alternative test methods,
  • the rapid time of analysis following sample preparation (seconds to tens of minutes),
  • the potential for non-destructive testing of samples in certain instances so that specimens can be preserved for other needs,
  • the broad range of elements that can be measured including metals, nonmetals and halides,
  • the general insensitivity of x-ray spectra to chemical bonding and oxidation state,
  • the wide dynamic range of concentration that the method can accommodate (trace to 100%),
  • the high precision of analysis and the potential for high accuracy with suitable methodology,
  • the ease-of-use and sophistication of mathematical methods to reduce or eliminate the reliance on matrix-matched calibration standards in quantitative analysis,
  • the ability to perform semiquantitative surveys of elemental composition of complete unknown samples in a “standardless” fashion,
  • the high spectral resolution of the method, especially for wavelength-dispersive instrument systems,
  • the ability of many systems to measure a range of spot sizes ideally suited to the application,
  • the applicability of the technique for measuring the thickness and composition of single and multilayer thin films, coatings and platings,
  • the ruggedness, portability and adaptability of certain instrument designs for mobile labs and manufacturing environments,
  • the short-term and long-term stability of the instruments, and
  • the relatively low cost of ownership, especially in the case of energy-dispersive instruments systems.

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