Measuring Range 0.015 to 0.03% 0.03 to 0.6% 0.6 to 1.2% Number of Pump Strokes 2 1 1/2 Correction Factor 1/2 1 2 Sampling Time 1 minute per pump stroke Detecting Limit 0.003% (n = 2) Color Change Orange → Dark green Reaction Principle CnHm + Cr6++ H2SO4 → Cr3+ Coefficient of Variation 10% (for 0.03 to 0.1 %), 5% (for 0.1 to 0.6 %) 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 color by itself Acetylene 3% Yes Produce dark brown to whole layer Propane 0.2% Yes Produce dark brown to whole layer (2%) Aromatic HCs 500 ppm Plus error Produce dark green (5000ppm) Alcohols, Esters, Ethers - Plus error Produce dark green Halogenated HCs. 5000 ppm Plus error Produce dark green (5000ppm) Hydrogen sulfide 500 ppm Plus error Produce dark green (5000ppm) Sulfur dioxide 500 ppm Plus error Produce green (5000ppm)