Volumetric KF Analysis : 15.66%Oven Water Standard

The application (download below) describes the automated volumetric Karl Fischer titration of 15.66% oven water standard for checking the system suitability of the coupled analystical system consisting of titrator and oven.

Background:

Sodium tartrate di-hydrate is the volumetric standard for Karl Fischer titration. It has stoichiometric water content of 15.66%. To achieve a gas phase extraction of the water molecules present in the di-sodium tartrate di-hydrate crystal lattice, he recommended heating temperature of the KF oven is 180°C.

For Gas phase extraction , the air flow is used as carrier gas to transfer evaporated moisture in the titration cell. Air is aspirated by a pump and first passed through a drying unit filled with silica gel to absorb large amount of air moisture. Subsequently, this flow is passed through a second drying unit filled with molecular sieve to adsorb traces of water.A digital gas flow control regulates the flow rate defined in the titration method. The dry air flow is passed through the KF oven and then in the titration cell. In this way, evaporated water from the sample is transferred in the titration cell and absorbed by the KF solvent solution for subsequent titration.

The water standard  can be used to verify the performance of the coupled analytical system consisting of a Karl Fischer volumetric titrator with a KF oven.The acceptance criteria for the system has been defined in terms of recovery rate and repeatability.

[For Coulometric analysis download application 'Automated Coulometric KF analysis of 15.66% oven water standard' ]