Energy dispersive X-ray microanalysis (EDX) is an electron beam induced X-ray spectrochemical technique compatible with both TEM and SEM, which allows the determination of the local chemical composition of a solid sample by means of an in situ, non-destructive, analysis on a microscopic scale. In both types of microscope, the electron beam is focused on an area of interest of the specimen. As a result of the interactions between the impinging electrons and the target atoms, X-rays are emitted which are characteristic in energy for the constituent chemical elements. A histogram of the X-ray intensities versus their energy, called an X-ray spectrum, enables the identification and even quantification of the chemical elements present in the specimen.

Element analysis of three different specimen grids (cupper, nickel and gold) imaged on top of a one cent coin (M. Lindman & E. Jokitalo).

Our new SEM does not have EDX detector. Nearest SEM equipped for EDX can be found in the Kumpula campus, Laboratory of Inorganic Chemistry.

Barium sulfate is used as a contrast agent to improve the visualization of the gastrointestinal tract in an x-ray image. In this TEM image of ultrathin section of human tissue, a large aggregate was found among blood cells, which element analysis showed to be barium sulphate precipitate (P. Lunetta).