Application Notes: Reflectometry – Total Sugar (Glucose and Fructose) in Honey

Reflectometric determination after enzymatic conversion with glucose-6-phosphate dehydrogenase and diaphorase


Cat. No. 116136 Reflectoquant® Total Sugar Test
Cat. No. 117246 Reflectometer RQflex® 20

This application note pertains to RQflex® 20 and all discontinued instruments (RQflex® 10, RQflex® plus)

Sample preparation:

Homogenize the honey sample by stirring with a glass rod. Exactly weigh 1.0 g of honey into a 200-ml glass beaker and with stirring dissolve with 80 ml of distilled water. Quantitatively transfer to a 100-ml volumetric flask, make up to the mark with distilled water, and mix thoroughly. Subsequently draw off 1.0 ml, place this volume in a 25 ml volumetric flask, and make up to the mark with distilled water. Use this sample for the analysis.


To the test glass add 10 ml of distilled water, 5 drops of reagent TS-1, and 1 ml of the prepared sample and swirl.

Press the START button of the reflectometer and at the same time immerse both reaction zones of the test strip in the measurement sample (23 + 3 °C) for approx. 2 s. Allow excess liquid to run off via the long edge of the strip onto an absorbent paper towel. Immediately insert the test strip into the strip adapter.

After 600 s the strip is measured in the reflectometer. The result [mg/l] is automatically stored. (Please refer to the RQflex® operating instructions and the package insert of the Reflectoquant® Total SugarTest.)

Serial measurements:

After the first measurement, any number of further measurements can be made by pressing the START button. This, however, requires the use of a stopwatch, since the countdown function of the reflectometers is available only for the first measurement.

The detection zones of the test strip must be appropriately protected from light during the reaction time.


Total sugar content [mg/kg] = Result [mg/l] x 2500 [ml]
Sample weight [g]
Total sugar content [g/kg] = Result [mg/l] x 2500 [ml]
Sample weight [g] x 1000

Measurement results:

Sample Reflectoquant® [g/kg] Enzymatic [g/kg]
1 716 706
2 703 693
3 787 813


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