Energy-Dispersive X-ray Spectroscopy (EDS or EDX) is a technique used in microanalysis to determine which elements are present in a very small sample and sometimes their approximate amounts.
How EDS Works:
- A sample is bombarded with high-energy electrons (usually from a Scanning Electron Microscope, SEM).
- These electrons knock inner-shell electrons out of atoms in the sample.
- When outer-shell electrons fall into the empty spots, they emit X-rays.
- Each element emits X-rays with characteristic energies, acting like a “fingerprint” for that element.
What EDS is Used for:
- Element Identification
- Detects which elements (like C, O, Na, Fe, etc.) are present in a tiny area of a sample.
- Elemental Mapping
- Shows how different elements are distributed across the surface of a sample.
- Quantitative Analysis
- Estimates the relative amounts of elements in the sample (in percent).
- Microanalysis Applications
- Materials science: Checking alloy composition or surface coatings.
- Forensics: Analyzing tiny paint chips or glass fragments.
- Environmental studies: Detecting pollutants in dust or soil particles.
- Pharmaceuticals: Studying impurities in drugs or tablets.
In short:
EDS is used in microanalysis to identify and measure elements in very small samples, often in combination with SEM, giving both structural and compositional information.