Indicator: 0.2 to 20 ppm
Measuring Range:
+ 0.2 to 20 ppm, Number of Pump Strokes 3
+ 20 to 66 ppm, Number of Pump Strokes 1
Sampling Time: 2 minute per pump stroke
Colour Change: White → Brown
Reaction Principle: 2C6H6+ HCHO → C6H5CH2C6H5 + H2O, C6H5CH2C6H5 + H2S2O7 → Condensation polymer
Coefficient of Variation: 10% (for 0.2 to 5ppm) , 5% (for 5 to 20 ppm)
Nr. of tests: 5
Pump: GV-100S/110S
Details
Catalog
Manual
Performance
Measuring Range |
0.2 to 20 ppm |
20 to 66 ppm |
Number of Pump Strokes |
3 |
1 |
Correction Factor |
1 |
3.3 |
Sampling Time |
2 minutes per pump stroke |
Detecting Limit |
0.1 ppm (n=3) |
Colour Change |
White → Brown |
Reaction Principle |
2C6H6+ HCHO → C6H5CH2C6H5 + H2O C6H5CH2C6H5 + H2S2O7 → Condensation polymer |
Coefficient of Variation |
10% (for 0.2 to 5ppm) , 5% (for 5 to 20 ppm) |
Shelf Life |
2 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 |
≦ 500 ppm |
No |
No |
Toluene |
≦ 300 ppm |
No |
No |
Xylene |
≦ 350 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. |
Calibration gas generation |
Diffusion tube method |
TLV-TWA |
TLV-STEL |
Explosive range |
0.5 ppm |
2.5 ppm |
1.3 to 7.1% |