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

Getting Started Model 9110EH Instruction Manual
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 9110EH 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 9110EH 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.
30 M9110EH Rev 0