Ultraviolet Light - UV/NDUV

Ultraviolet (UV) light is often used for the analysis of NO, NO₂ and SO₂. Often, when the UV measuring principle is used it is actually the NDUV (Non Dispersive Ultraviolet) principle. The measurement is made by leading a gas flow through a cuvette where the UV light source and the optical filter have been placed at one end of the cuvette and a detector has been placed at the other end. The UV light source sends out a scattered UV light, and the wave length of the light that is led through the gas in the cuvette is determined by the optical filter installed between the light source and the cuvette. Different kinds of wave lengths of UV light are used to analyse different gasses. The absorption of the light that is sent into the cuvette is an expression of the concentration of the gas to be analysed. The amount of light passing through the gas is measured by the detector at the other end of the cuvette.

The UV measurement principle is generally not as cross-sensitive towards other gasses such as CO₂ and H₂O as these do not absorb well in the UV area. This is why the UV measuring principle is very useful for the analysis of gasses in low concentrations of especially SO₂ and NO₂.

No item found