| Formaldehyde | HCHO | NO.91M | |
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| Performance |
|
Measuring Range |
8 to 20ppm |
20 to 2000ppm |
2000 to 6400ppm |
|
Number of Pump Strokes |
2 |
1 |
1/2 |
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Correction Factor |
0.4 |
1 |
3.2 |
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Sampling Time |
1.5 minutes per pump stroke |
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|
Detecting Limit |
4 ppm (n=2) |
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Color Change |
Yellow |
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Reaction Principle |
3HCHO + (NH2OH)3H3PO4 |
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| Coefficient of Variation | 10% (for 8 to 200 ppm), 5% (for 500 to 2000 ppm) | ||
| Shelf Life | 2 Years | ||
| Corrections for temperature & humidity |
Temperature correction is necessary | ||
| Store the tubes in the refrigerator to keep at 10oC (50oF) or below. | |||
| Possible coexisting substances and their interferences | (NOTE) |
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Substance |
Concentration |
Interference |
Change color by itself |
|
Acrolein |
5 times |
Plus error |
Produces red stain at 20 ppm |
|
Acetaldehyde |
1/6 time |
Plus error |
Produces red stain at 3 ppm |
| Calibration gas generation | Diffusion tube method | |
| TLV-TWA | TLV-STEL | Explosive range |
| - | C 0.3ppm | 7.0 to 73% |
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| Copyright(c) 2001 GASTEC CORPORATION. All rights reserved. |
Red
H3PO4
Phosphate