Emission spectroscopy is a technique which observes the photons emitted by an element which is excited by an energy source. This is a plasma generated by inductive coupling.
We use an argon plasma which is ionized and transmits part of this energy to the sample to atomize it, excite or even ionize it. The reaction which takes place in a plasma torch is initiated and maintained by an HF magnetic field induced by an induction coil.
The photon, characteristic of an element, will be emitted during its de-excitation at a certain wavelength. The observation of the signal (the light emitted when the atoms return to the ground state) is carried out by axial or radial sighting. The array + prism combination allows the spread of the spectrum in 2D. The image is then focused by the mirror and returned to the CID detector (Charge Injection Device).
Each element has a characteristic optical emission spectrum. The intensity of the lines emitted by the sample being proportional to the concentration of elements, the metering of metals is carried out according to a range of standards of known concentrations.
This technique is one of the most commonly used for determining the concentrations of elements in a sample.