Nitrogen oxides |
NO.11HA |
| NO+NO2 |  |
 |
Performance
| Measuring Range | 50 to 2500 ppm |
| Number of Pump Strokes | 1 |
| Correction Factor | 1 |
| Sampling Time | 1 minute per pump stroke |
| Detecting Limit | 10 ppm (n=1) |
| Colour Change | White → Green |
| Reaction Principle | NO + Cr6+ + H2SO4 →NO2 NO2 + (C6H5)2NH Green product |
| Coefficient of Variation | 10% (for 50 to 400 ppm), 5% (for 400 to 2500 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 | 500 ppm | Unclear demarcation | Bluish purple ( 100 ppm) |
| Ozone | 200 ppm | Unclear demarcation two layers | Brown |
| sulphur dioxide, Hydrogen sulphide | No | 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 | - |
