Method: Reflectometric determination after reaction with
4-amino-3-hydrazino-5-mercapto-1,2,4-triazole

Reagents:
Reflectoquant^® Formaldehyde Test, Cat.No. 1.16989.0001
Reflectometer RQflex, Cat.No. 1.16970.0001 or RQflex plus cat. no. 1.16955.0001

Sample preparation:
Weigh about 10 g sample exactly into a beaker and add at least 50 ml of destilled water. Stir thoroughly.

Analysis:
Rinse the test vessel with the pretreated sample solution and fill to the 5-ml mark. Add 10 drops of reagent Fo-1 and swirl. Press START button and simultaneously immerse both reaction zones of the test strip in the sample solution (15 - 30°C) for approx. 2 seconds. Shake off excess liquid from the strip.

Wait 120 seconds and then measure the strip in the reflectometer. The value [mg/l] will be stored automatically. (Please refer to the RQflex operating instructions and the package insert of the Reflectoquant^® Formaldehyde Test).

Calculation:
Formaldehyde content [mg/kg] = Measured value [mg/l] x Vol. of water [ml]
Weight of sample [g]