Application Range
Standard Measuring Range: 15 to 420 ppm
Number of Strokes (n): 20 to 2
Time for Measurement: max. 4 min
Standard Deviation: ±30%
Color Change: white -› red brown
Ambient Operating Conditions
Temperature: 0 to 30 °C
Absolute Humidity: max. 30 mg H2O / L
Reaction Principle
a) 2 C6H6 + HCHO -> C6H5-CH2-C6H5 + H2O
b) C6H5-CH2-C6H5 + H2SO4 -> p-quinoid compound
Cross Sensitivity
Other aromatics (toluene, xylene) are retained in the pre-layer causing a reddish brown discoloration. If the toluene or xylene concentrations are too high the entire pre-layer up to the indicating layer is discolored making a benzene measurement impossible. Petroleum hydrocarbons, alcohols and esters do not affect the indication.