Oxides of Nitrogen

Signal’s analysers are recognised as the best practical analytical method for NOx detection in a wide variety of applications.

This is a term generally meaning the sum of nitric oxide and nitrogen dioxide. There are two widely used methods for measuring NO, infra-red and chemiluminescence, NO2 is then measured by first converting it to NO using a catalyst, to give a reading for the total NOx. NO and NO2 can also be measured at low levels in ambient air using electrochemical cell technology.  This is a lower cost alternative but has limitations in terms of accuracy due to potential cross sensitivity and high temperature and humidity effects.


Non Dispersive Infrared (NDIR) Multi-gas analysers are available in 1, 2, 3, 4 or 5 gas channel configurations, offering high levels of performance and flexibility. Options include CO, CO2, CH4, NO, N2O, SO2, HCl and O2.

low ranges E.g. 0-10 ppm CO

5 user-configurable ranges + autorange per channel

electronic pressure & temperature compensation

RS232 'AK' protocol, 4-20mA & 0-10VDC chart outputs


Chemiluminescent Detector (CLD) NOX analysers for NO/NO2/NOx measurement in engine emissions, combustion studies, process plant, Emission monitoring and medical gas production.

very low quenching from CO2 and H2O

electronic proportional flow controllers

special ozone generator uses air as feed gas

long life NOx converter (5 years)

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