Determination of Water Content in 1,2-Cyclohexanedione Using Karl Fischer Titration

Product Group


General Information concerning the product group


During water determination after Karl Fischer (KF) aldehydes and ketones cause side reactions with the normally utilised methanol. Both side reactions, i.e. the formation of acetals and ketals, as well as bisulphite addition, can often be recognised by dragging end points and lead to wrong results. During acetal or ketal formation water is released which simulates water contents that are too high. Bisulphite addition, however, consumes water, leading to results that are too low. The extent of the interferences depends on the reactivity of the substances as well as the reactivity of the utilised KF solutions. Through utilisation of specific KF reagents for aldehydes and ketones it is possible to largely suppress the side reactions. The coulometric method is not recommended.

Special Information concerning the sample and the methods

Diketones are only slightly more reactive than normal ketones. For neighbouring keto groups the influence of disturbing side reactions, however, increases erratically. 1,2-Cyclohexanedione is one of the most reactive ketones. The formation of ketals with methanol and especially bisulphite addition are characteristic and require KF titration with specific reagents for aldehydes and ketones. Only small samples may be analysed.

Titration one component system


188006 Aquastar® - CombiTitrant 5 Keto - One component reagent for volumetric Karl Fischer titration of aldehydes & ketones, 1 mL = approx. 5 mg water

30 mL 188007 Aquastar® - CombiSolvent Keto - Solvent for volumetric Karl Fischer titration with one component reagents for aldehydes & ketones

Titration Parameters:
Titration settings for methanol-free solvents:
I(pol) = 20 µA, U(EP) = 100 - 250 mV
Stop criterion for fast end point: drift < 30 µL/min

Sample size:
0.5 - 1 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. Titration is carried out to fast end point.


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