Hydrogen sulphide, sulphur Dioxide

NO.45S
H2S+SO2 (Separete quantification)
Performance
Name of Gas
SO2
tube
H2S
tube
SO2
tube
H2S
tube
SO2
tube
H2S
tube
Measuring Range
0.25 to
0.5
1.25 to
2.5
0.5 to
10
2.5 to
60
10 to
20
60 to
120
Number of Pump Strokes
2 2 1 1 1/2 1/2
Correction Factor
1/2 1/2 1 1 2 2
Sampling Time 1.5 minute per pump stroke
Detecting Limit 0.05 ppm (n=2)
Colour Change SO2tube : Yellowish green → Yellow
H2S tube : White → Brown
Reaction Principle SO2tube:
SO2 + BaCl2+ H2O → BaSO3 + 2HCl
HCl + Base → Chloride

H2S tube:
H2S + Pb(CH3COO)2 → PbS + 2CH3COOH
Coefficient of Variation SO2 tube: 10% (for 0.5 to 2 ppm), 5% (for 2 to 10 ppm)
H2S tube:10% (for 2.5 to 10 ppm), 5% (for 10 to 60 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
SO2 tube H2S tube SO2 tube H2S tube
Nitrogen dioxide 5 ppm + No Pale purple No
Nitrogen monoxide
Mercaptans
Carabon monoxide
  No No No
Calibration gas generation Permeation tube method
TLV-TWA TLV-STEL Explosive range
SO2 : 2 ppm
H2S : 10 ppm
SO2 : 5 ppm
H2S : 15 ppm
H2S : 4.0 to 44%


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