Application Range
Standard Measuring Range: 0.05 ppm Dichlorvos
Number of Strokes n: 10
Time for Measurement: approx. 5 min
Standard Deviation: ± 30 %
Color Change: yellow -> red
Ambient Operating Conditions
Temperature: 10 to 40 °C
Absolute Humidity: 3 to 18 mg H2O / L
Reaction Principle
a) (CH3O)2PO2-CH=CCI2 + Cholinesterase ¨ inactive enzyme
b) Butyrylcholine iodide + H2O -> Butyric acid
c) Butyric acid + Phenol red -> yellow reaction product If phosphoric acid esters are present the enzyme is inactivated and butyric acid will not form, thus the weak alkali solution colors the indicating layer red and must be stable for 1min. If the enzyme remains active, phosphoric acid esters are not present, and the indicating layer remains yellow because of butyric acid formation.
Cross Sensitivity
Other phosphoric acid esters than dichlorvos are also indicated, but with different sensitivities.
Additional Information
After performing the required 10 pump strokes the reagent ampoule must be broken and the liquid transferred to the enzyme layer by gently tapping
the side of the tube. The substrate layer must not become wet After waiting one (1) minute the liquid must be carefully drawn up to the marking line
using the pump. Wait another minute before drawing the liquid onto the indication layer using the pump.