WHAT IT IS
A grating is a key optical component in the spectrometer that separates light into its individual wavelengths through diffraction. It consists of a surface with precisely spaced grooves or lines that diffract light into multiple beams, each corresponding to a specific wavelength. The dispersed light is then directed to the detector for analysis, allowing the identification and quantification of elements in the sample.
The wavelength range in ICP-OES refers to the span of electromagnetic spectrum wavelengths that the instrument can measure. Typically, ICP-OES systems operate in the ultraviolet (UV) and visible (VIS) regions, covering a range from approximately 160 to 900 nanometers (nm). This wide range ensures the detection of most elements, as each has unique emission lines within this spectrum.
HOW IT WORKS
Light Emission from Plasma – The plasma excites atoms and ions in the sample, causing them to emit light at element-specific wavelengths.
Light Dispersion – The grating diffracts the emitted light, separating it into individual wavelengths.
Wavelength Selection – The spectrometer isolates the desired wavelengths corresponding to the target elements.
Detection – The isolated light is measured by detectors such as charge-coupled devices (CCDs) or photomultiplier tubes (PMTs), providing data for elemental analysis.
Data Processing – The intensity of the measured wavelengths is correlated with element concentrations in the sample.
TYPES OF GRATINGS IN ICP-OES
Echelle Gratings: These gratings are used in high-resolution spectrometers and combine with cross-dispersers to achieve a broad wavelength range and high resolution.
Plane Gratings: Flat gratings with finely spaced grooves, ideal for applications requiring a narrow wavelength range and precise resolution.
Holographic Gratings: Manufactured using advanced techniques for minimal stray light, improving signal quality and data accuracy.