Benzene |
NO.121S |
| C6H6 |  |
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Performance
| Measuring Range |
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| Number of Pump Strokes |
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| Correction Factor |
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| Sampling Time | 2 minutes per pump stroke | |||
| Detecting Limit | 0.5 ppm (n=4) | |||
| Colour Change | White → Dark green | |||
| Reaction Principle | C6H6 + I2O5 + H2S2O7 → I2 | |||
| Coefficient of Variation | 20% (for 5 to 40 ppm), 15% (for 40 to 120 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 |
| Hexane | 100 ppm | No | No |
| Toluene | 200 ppm | No | No |
| Xylene | 300 ppm | No | No |
Aromatic hydrocarbons other than benzene are trapped in the brown layer in the pretreatment tube. If the pretreatment reagent is entirely consumed (whole brown layer turns to dark brown), a higher reading will be given. |
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| Calibration gas generation | Diffusion tube method |
| TLV-TWA | TLV-STEL | Explosive range |
| 0.5 ppm | 2.5 ppm | 1.3 to 7.1% |
