Teledyne 9110E - Nitrogen Oxides Analyzer - Manual (Page 44)

Getting Started Model 9110E Instruction Manual
30 M9110E Rev B
3.6.2. Interferences for NO
X
Measurements
The chemiluminescence method for detecting NO
X
is subject to interference from a number
of sources including water vapor (H
2
O), ammonia (NH
3
), sulfur dioxide (SO
2
) and carbon
dioxide (CO
2
) but the Model 9110E has been designed to reject most of these interferences.
Section 10.1.5 contains more detailed information on interferences.
Ammonia is the most common interferent, which is converted to NO in the analyzer’s NO
2
converter and creates a NO
X
signal artifact. If the Model 9110E is installed in an
environment with high ammonia, steps should be taken to remove the interferent from the
sample gas before it enters the reaction cell. TAI offers a sample gas conditioning option to
remove ammonia and water vapor (Section 5.8).
Carbon dioxide diminishes the NO
X
signal when present in high concentrations. If the
analyzer is used in an application with excess CO
2
, contact TAI customer service for possible
solutions. Excess water vapor can be removed with one of the dryer options described in
Section 5.8. In ambient air applications, SO
2
interference is usually negligible.
NOTE
Once you have completed the above set-up procedures, please fill out the quality
questionnaire that was shipped with your unit and return it to TAI.
This information is vital to our efforts in continuously improving our service
and our products. Thank you.