Measuring Range 10 to 20 ppm 20 to 500 ppm 500 to 1000 ppm Number of Pump Strokes 2 1 1/2 Correction Factor 1/2 1 2 Sampling Time 1 minute per pump stroke Detecting Limit 2.5 ppm (n=2) Color Change Yellow → Red Reaction Principle Hydrogen chloride reacts with indicator to produce red stain. HCl + Indicator → Chemical reaction compound Coefficient of Variation 10% (for 20 to 100 ppm), 5% (for 100 to 500 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 Hydrogen fluoride 600 ppm Plus error Produces red stain Nitric Acid 1/10 time Plus error Produces red stain Nitrogen dioxide 1/2 time Plus error. Produces red stain (500 ppm)