Application Range: Standard Measuring Range: 10 to 200 / 1 to 20 ppm Number of Strokes n: 1 / 10 Time for Measurement: Approx. 1 min / 10 min Standard Deviation: ± 15 % Color Change: White → Brown Ambient Operating Conditions: Temperature: 2 to 40 °C Absolute Humidity: max. 40 mg H2O / LL Reaction Principle: H2S + Cu2 → CuS + 2H+ Cross Sensitivity: 500 ppm hydrochloric acid, 500 ppm sulfur dioxide, 500 ppm ammonia or 100 ppm arsine do not interfere with the reading. Methyl mercaptan and ethyl mercaptan change the entire indicating layer to a pale yellow. When mixed with hydrogen sulfide, the reading is extended by approx. 30%.