XRF

X-ray fluorescence (XRF) is an analytical technique used to determine the elemental composition of materials. It relies on irradiation of a sample with primary X-rays, which eject inner-shell electrons from atoms and cause the emission of characteristic secondary X-rays. The energies of these emitted photons are specific to the elements present, and their intensities relate to element concentration.

Instruments include energy-dispersive XRF (EDXRF) and wavelength-dispersive XRF (WDXRF). EDXRF measures a broad energy range with a common detector, enabling rapid screening. WDXRF uses crystal analyzers to separate X-ray wavelengths with higher spectral resolution, improving peak separation. Other modes include total reflection XRF (TXRF) for trace analysis, micro-XRF for spatially resolved elemental mapping, and portable XRF (pXRF) for field measurements.

Applications span geology and mineralogy, metallurgy and alloy analysis, archaeology and art conservation, environmental monitoring, forensics, plastics and cement, and semiconductor materials. XRF is valued for being non-destructive, requiring minimal sample preparation, and enabling multi-element analysis across a wide range of elements.

Quantitative results require calibration with standards and correction for matrix effects, using fundamental parameters or empirical methods. Detection limits depend on the element, sample matrix, geometry, and instrument configuration; light elements (low Z) are more challenging, and spectral overlaps can complicate interpretation.

Safety considerations include exposure to X-rays and emitted radiation, necessitating shielding and trained operators. XRF provides rapid, non-destructive analysis, but accurate interpretation requires understanding of calibration, matrix effects, and instrument response.