Measuring Range 2 to 20ppm 20 to 50ppm 50 to 100ppm Number of Pump Strokes 2 1 1/2 Correction Factor 1 2.5 5 Sampling Time 1 minute per pump stroke Detecting Limit 0.5 ppm (n=2) Color Change White → Brown Reaction Principle HCHO + C6H4(CH3)2 + H2S2O7 → Condensation Polymer Coefficient of Variation 15% (for 2 to 6 ppm), 10% (for 6 to 20 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 color by itself Aldehydes 1/2 time Plus error Produce brown stain Esters, Ethers 1000 ppm Plus error No discoloration Ketones 1000 ppm Plus error No discoloration Styrene 500 ppm Plus error Yellow at 500 ppm