Instrument - Thermo Fisher Model 42i Chemiluminescence NO-NO2-NOx Analyzer

Short name:
NOx box

Full name:
Thermo Fisher Model 42i Chemiluminescence NO-NO2-NOx Analyzer

What is being measured:
Nitrogen oxides

Sampling Protocol:

Thermo Fisher

Model 42i

Instrument year :
None specified

Data recording software:

Data analysis software:

Raw data time resolution:
10 seconds

Analysis data averaging:

Detection limit:
0.4 ppb

Sensitivity to temperature (and correction method, if applicable): :

Sensitivity to relative humidity (and correction method, if applicable): :

Sampling method:

Sample preparation method:

Sample residence time (chamber to instrument) (seconds):

Length of tubing (cm):

Instrument flow rate:

Tubing inner diameter:

Tubing material:
PFA Teflon

Chemical identification method:
This instrument measures NO using its chemiluminescent reaction with ozone. It also measures total NOx by passing the sample flow through a molybdenum catalyst to convert it to NO, before measuring this in the same manner. NO2 concentration is calculated by subtracting the NO measurement from the total NOx measurement. The catalyst also converts some NOy species including HONO to NO and as such these are detected as "NO2."

Data analysis method:

Quantification method:

Calibration method:
Calibration is performed using standard tanks of NO and NO2.

Calibration drift estimate:

Calibration schedule:

Uncertainty estimation method:
Uncertainty from factory specifications is +- ~1%. Uncertainty arising from error in dilution of calibration gases is likely closer to +- 10%.

Known interferences:
NOy species, most notably HONO in our reaction systems, are detected as "NO2"

Link to supplemental information:

Additional notes:

Measurement uncertainty:

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