Nitrogen oxides |
NO.11S |
| NO+NO2 |  |
 |
Performance
| Measuring Range |
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| Number of Pump Strokes |
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| Correction Factor |
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| Sampling Time | 1 minute per pump stroke | |||
| Detecting Limit | 2 ppm (n=2) | |||
| Colour Change | White → Pale green | |||
| Reaction Principle | NO + Cr6+ + H2SO4 →NO2 NO2 + (C6H5)2NH Pale green product |
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| Coefficient of Variation | 10% (for 10 to 40 ppm), 5% (for 40 to 250 ppm) | |||
| Shelf Life | 2 Years | |||
| Corrections for temperature & humidity | Unnecessary | |||
| Store the tubes at cool and dark place. | ||||
Possible coexisting substances and their interferences (NOTE)
| Substance | Concentration | Interference | Change colour by itself to |
| Hydrogen chloride | 50 ppm | + | Bluish purple (10 ppm) |
| Ozone | 80 ppm | two layers | Pale brown |
| sulphur dioxide, Hydrogen sulphide |
1/1 | + | No |
| Methanol | 400 ppm |  |
No |
| Calibration gas generation | NO2:Permeation tube method NO:High pressure gas cylinder method |
| TLV-TWA | TLV-STEL | Explosive range |
| NO2: 3 ppm NO: 25 ppm |
NO2: 5 ppm | - |
