X-Ray Fluorescence Spectrometry XFS

X-Ray Fluorescence Spectrometry (XFS) : 

Principle: When a sample is placed in a beam of primary X-rays, part of it will be absorbed 

and the atoms get excited, by the ejection of electrons present in K and L shells. While 

relaxing they re-emit X-rays of characteristic wavelength. This re-emitted X-rays are called 

secondary or fluorescent X-rays  and hence the name for this technique. Since, the 

wavelength of the fluorescence is characteristic of the element being excited, measurement of 

the wavelength and intensity enables to carry out the qualitative and quantitative analyses. 

Instrumentation:  It comprises of a source for primary X-rays, collimators, analyzing crystal 

and detector.  

Applications:    It is one of the non-destructive methods in the elemental analysis of solid or 

liquid samples for major and minor constituents. Most of the elements in the periodic table, 

both metals and nonmetals, respond to this technique. Detection limit is between 10 to 100 

ppm. One of the significant uses of this method is in the medical field in identifying and 

determining the sulfur in protein.  

Disadvantages:  The sensitivity gets affected for elements with lower atomic numbers, 

particularly elements with atomic number  lower than 15 are difficult to analyze. The 

sensitivity is also limited by matrix absorption, secondary fluorescence and scattering of the 

particles. Instruments are often large, complicated and costly.