Determination of Water Content in Mashed potatoes Using Karl Fischer Titration

Product Group


General Information concerning the product group


Foodstuffs encompass the most diverse products. Depending on whether carbohydrate-rich, fatty or proteinrich substances are under investigation, different working techniques are favourable. Complex matrices that dissolve slowly, or where the water can only be slowly extracted, necessitate the use of solubilisers. In addition, titration under heating and the application of a homogeniser to accelerate water release are expedient.

Special Information concerning the sample and the methods

The extraction of water in mashed potatoes is sluggish. The presence of formamide during the direct volumetric determination increases the extraction of water. Alternatively, titration may be carried out under warm conditions (50 °C). The use of a homogeniser is also favourable. The coulometric method can only be applied in combination with KF oven technology. For the release of water temperature of between 160 °C is recommended.

Titration one component system


188005 Aquastar™ - CombiTitrant 5 - One component reagent for volumetric Karl Fischer titration, 1 mL = approx. 5 mg water
188002 Aquastar™ - CombiTitrant 2 - One component reagent for volumetric Karl Fischer titration, 1 mL = approx. 2 mg water

30 mL 188009 Aquastar™ - CombiMethanol - Solvent for volumetric Karl Fischer titration with one component reagents, max. 0.01 % water
30 mL 109684 Formamide - null

Titration Parameters:
Extraktiontime: 180 sec
Temperatur: 50°C
Default titration settings, e.g.:
I(pol) = 20 - 50 µA, U(EP) = 100 - 250 mV
Stop criterion: drift < 20 µL/min

Sample size:
0,15 - 0,25 g

The titration medium is first placed into the cell and titrated dry by means of the titrant. Then the sample is added from a weighing boat (exact sample weight determination by weighing of weighing boat before and after addition) and the titration is started.


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