Scanning Electron Microscopy with Energy-Dispersive X-ray Spectrometry (SEM-EDX)

Scanning Electron Microscopy

SEM-EDX is a combination of two approaches to analysis. A scanning electron microscope (SEM) uses an electron beam to view a sample, compared to a normal microscope that uses light. The higher energy of the electron beam permits viewing at much higher magnifications than is possible with light. Energy dispersive x-ray spectrometry takes advantage of the phenomenon that when a material is irradiated with a high-energy electron beam, the sample will emit x-rays. The x-rays have energies that are characteristic of the elements being irradiated. This permits the identification of the elements present in anything that we can view in the SEM.

Fig. 3 - SEM-EDX ParticlesFig. 3 – SEM-EDX ParticlesFig. 4 - SEM-EDXFig. 4 – SEM-EDX
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Sometimes small particles are observed in beverages or drug solutions where they don’t belong. To correct the problem, the manufacturer needs to know what the particles are. Figure 3 shows a blister in the coating on the inside of a beverage can.

The issue causing the blister was found to be microscopic particles of copper and chlorine trapped between the ID of the can and the can’s liner, which caused corrosion of the aluminum surface.  Figure 4 shows how our elemental mapping capabilities clearly indicated contamination at the manufacturer’s site.