Sulphur dioxide

Measuring Range
0.1 to 0.25 ppm (0.25) to 10 ppm 10 to 25 ppm
Number of Pump Strokes
4 2 1
Correction Factor
0.4 1 2.5
Sampling Time 2 minutes per pump stroke
Detecting Limit 0.02 ppm (n=4)
Colour Change Bluish purple → White
Reaction Principle SO2 +I2 +2H2O H2SO4 + 2HCl
Coefficient of Variation 10% (for 0.25 to 2 ppm), 5% (for 2 to 10 ppm)
Shelf Life 3 Years
Corrections for temperature & humidity Temperature correction is necessary
Store the tubes at cool and dark place.
Possible coexisting substances and their interferences (NOTE)
Substance Concentration Interference Change colour by itself to
Nitrogen dioxide  
(Unclear demarcation)
Brown (approx.1mm long from the inlet)
Hydrogen sulphide 1/10 + White
Calibration gas generation Permeation tube method
TLV-TWA TLV-STEL Explosive range
2 ppm 5 ppm -

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