Question

Chemical reaction during no test by chemiluminescence analyzer

Answer 1

NO is a relatively unstable molecule which will oxidize to NO2 (especially) in the presence of O3 . This reaction produces a quantity of light for each NO molecule which is reacted.

This light can be measured using a photomultiplier tube or solid state device.

If the volumes of sample gas and excess ozone are carefully controlled, the light level in the reaction chamber is proportional th the concentration of NO in the gas sample