简单介绍： 甲醛检测管91m hcho formaldehyde，measuring range 8 to 20ppm 20 to 2000ppm 2000 to 6400ppm number of pump strokes 2 1 1/2 correction factor 0.4 1 3.2 sampling，甲醛检测管价格
甲醛检测管91m hcho formaldehyde 产品详情
详情介绍：
甲醛检测管91m hcho formaldehyde
formaldehyde no.91mhchoperformance
measuring range
8 to 20ppm
20 to 2000ppm
2000 to 6400ppm
number of pump strokes
2
1
1/2
correction factor
0.4
1
3.2
sampling time
1.5 minutes per pump stroke
detecting limit
4 ppm (n=2)
color change
yellow → red
reaction principle
3hcho + (nh2oh)3h3po4 → h3po4
h3po4 + base → phosphate
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)
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
other substance measurable with this detector tube
calibration gas generation diffusion tube method
tlv-twa tlv-stel explosive range
- c 0.3ppm 7.0 to 73%