Energy Dispersive X-Ray Spectroscopy (EDS/EDX)
Energy Dispersive X-ray Spectroscopy (EDS or EDX) is an analytical technique used to identify and characterize the elemental composition of sample material.
Using a scanning electron microscope (SEM) equipped with an x-ray detector, atoms within a sample are excited by an electron beam. This beam interacts with the atom, displacing an electron out of its shell, leaving behind a void. Another electron from a higher energy level fills this void in the lower orbital. The energy released during this event is relative to the number of shells the replacement electron has displaced from its original location, and to what shell the electron moves. This energy is emitted as x-rays, which are converted into voltage by the detector. The resulting data consists of counts corresponding to the number of x-rays at each energy level. The energy level of the emitted x-rays correlates to individual elements, while the proportional counts relates to the quantity of the element.
As shown in the diagram, the movement from the L shell to the K shell would produce a Kα emission. If the same K position is filled from the M orbital, a Kβ emission would be produced. Alpha (α) emissions have the highest energy, but beta (β) emissions can give further insight into the element analyzed. Some elements may have emission energy overlaps, however, secondary α or β emissions can be used to distinguish one element from another. The cumulative spectrum of the emission energies for an element is unique to that element so it can be used to identify unknown particles in a sample or determine sample composition.
EDS technology from Particle Technology Labs is useful for analyzing the elemental composition of sample material for elements of atomic mass 12 (Carbon) and up, and can also be used to quantify the elemental composition of a sample. Results can be used for foreign material identification, process troubleshooting, deformulation, among other uses.
Note, in order to be analyzed by EDS, sample material must be able to be dried down prior to analysis. Material types we test include metals, metal oxides, unknowns, pharmaceuticals, proteins, ceramics, and more.
Contact PTL to discuss if your sample and project is appropriate for Energy Dispersive X-ray Spectroscopy analysis, and how this analytical technique can provide valuable information to your project.
Advantages
- Elemental composition
- Target individual particles
- Detection of metal atoms
Considerations
- Particulate must be dry prior to analysis
- Determines elemental composition for elements of atomic mass 12 (carbon) and up
- This technique does not offer full chemical composition analysis
- Background signal for smaller materials affecting composition percentages
Sample Requirements
Sample amount is not an easy question to answer, since it depends on the particle size and general nature of the material. Ideal sample amount is up to 500 mg for solid samples. For liquid samples, particulate would need to be captured and dried prior to analysis.
Smaller samples may be able to be run – please contact us to share specific information about your sample and options for suitable sample quantities.
Detection Range
Samples must be less than 25 mm in diameter. Target size will be dependent on the ability to resolve the particles. Feel free to contact us for further discussion.
Data Reported
A standard EDS package includes lower resolution backscatter SEM images of targeted areas of the sample, and a summary of the elemental analysis results for those targeted areas. Please reach out to discuss available options in more detail.
Sample Reports
Instrumentation
PTL uses the JEOL Neoscope II for our Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS/EDX) analyses.
