Measuring Range 0.05 to 1.0 ppm Number of Pump Strokes 5 Correction Factor 1 Sampling Time 1.5 minutes per pump stroke Detecting Limit 0.03 ppm (n=5) Color Change Yellowish Brown → Reddish Brown Reaction Principle 3HCHO + (NH2OH)3H3PO4 → H3PO4 H3PO4 + Base → Phosphate Coefficient of Variation 10% (for 0.05 to 0.3 ppm), 5% (for 0.5 to 1.0 ppm) Shelf Life 1 Year Corrections for temperature & humidity Temperature correction is necessary Store the tubes in the refrigerator to keep at 10oC (50oF) or below.
Possible coexisting substances and their interferences (NOTE)
Substance Concentration Interference Change color by itself Ammonia - Minus error Faint dull yellow color to whole layer Nitrogen dioxide - No effect Pale pink discoloration around zero Aldehydes 1/3 time Plus error (Unclear demarcation) Faint reddish brown to whole layer Ketones 1:1 Plus error (Unclear demarcation) Faint reddish brown to whole layer Toluene 10ppm No effect No discoloration