| Carbonyl sulfide | COS | NO.21 |
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| Performance |
|
Measuring Range |
5 to 10 ppm |
10 to 100 ppm |
100 to 200 ppm |
|
Number of Pump Strokes |
2 |
1 |
1/2 |
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Correction Factor |
1/2 |
1 |
2 |
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Sampling Time |
3 minutes per pump stroke |
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|
Detecting Limit |
1 ppm (n=2) |
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|
Color Change |
Blue |
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Reaction Formula |
COS is oxidezed by iodine pentoxide and sulfuric acid to generate SO2 in primary tube. The SO2 reacts with barium chloride to libraate hydrogen chloride which discolors pH indicator (BCG) to yellow. |
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| Coefficient of Variation | 10% (for 10 to 30 ppm), 5% (for 30 to 100 ppm) | ||
| Shelf Life | 2 Years | ||
| Corrections for temperature & humidity |
Unnecessary | ||
| Store the tubes in the refrigerator to keep at 10oC (50oF) or below. | |||
| Possible coexisting substances and their interferences | (NOTE) |
|
Substance |
Concentration |
Interference |
Change color by itself |
|
Carbon disulfide |
- |
Plus error |
Produce yellow stain |
|
Sulfur dioxide |
- |
Plus error |
Produce yellow stain |
|
Butane |
5000 ppm |
Minus error |
No discoloration |
|
Propane |
5000 ppm |
Minus error |
No discoloration |
| Calibration gas generation | High pressure gas cylinder method | |
| TLV-TWA | TLV-STEL | Explosive range |
| - | - | 12 to 19% |
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| Copyright(c) 2001 GASTEC CORPORATION. All rights reserved. |
Yellow
SO2 + CO2 SO2 + BaCl2 + H2O
BaSO3+ HCl