| Formaldehyde | HCHO | NO.91 | |
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| Performance |
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Measuring Range |
2 to 20ppm |
20 to 50ppm |
50 to 100ppm |
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Number of Pump Strokes |
2 |
1 |
1/2 |
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Correction Factor |
1 |
2.5 |
5 |
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Sampling Time |
1 minute per pump stroke |
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Detecting Limit |
0.5 ppm (n=2) |
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Color Change |
White |
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Reaction Principle |
Formaldehyde react with reaction agent to form a condensation |
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| Coefficient of Variation | 15% (for 2 to 6 ppm), 10% (for 6 to 20 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) |
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Substance |
Concentration |
Interference |
Change color by itself |
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Aldehydes |
1/2 time |
Plus error |
Produce brown stain |
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Esters, Ethers |
1000 ppm |
Plus error |
No discoloration |
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Ketones |
1000 ppm |
Plus error |
No discoloration |
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Styrene |
500 ppm | Plus error |
Yellow at 500 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. |
Brown