Hydrogen sulphide |
NO.4H |
| H2S |  |
 |
Performance
| Measuring Range |
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| Number of Pump Strokes |
|
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| Correction Factor |
|
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| Sampling Time | 30 seconds per pump stroke | |||
| Detecting Limit | 2 ppm (n=10) | |||
| Colour Change | White → Brown | |||
| Reaction Principle | H2S + Pb(CH3COO)2 → PbS + 2CH3COOH | |||
| Coefficient of Variation | 5% (for 100 to 2000 ppm) | |||
| Shelf Life | 3 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 |
| Ammonia | No | No | |
| Carbon monoxide, Carbon dioxide |
No | No | |
| sulphur dioxide | 1/1 | + | No |
| Mercaptans | No | No | |
| Organic substance | No | No | |
| Nitrogen dioxide | 1/4 |  |
No |
| Calibration gas generation | Permeation tube method |
| TLV-TWA | TLV-STEL | Explosive range |
| 1 ppm | 5 ppm | 4.0 to 44% |
