Tuesday, July 04, 2006

Low cost moisture content determinations

An elegant solution for moisture content determination is achieved by using a Karl Fischer oven, as with this technique only the water content of the sample is transferred to the titration cell
The water content of many samples is difficult to determine because they are only slightly soluble in alcohols, contaminate the titration cell, or have side reactions with Karl Fischer reagents. Traditional methods recommend the use of toxic solvents to promote dissolution of the sample or alternatively the samples require extensive preparation procedures. A more elegant solution is achieved by using a Karl Fischer oven, as with this technique only the water content of the sample is transferred to the titration cell.

However, instead of introducing the sample into the oven by means of a sample boat, the vial technique is used, ie the sample is weighed directly into the sample vial, sealed and transferred to the oven.

Combined with the sophisticated methodology of the 832 KF Thermoprep, this results in the following improvements in analysis: Strictly reproducible analysis conditions yield results with markedly improved precision: Manual sample preparation is reduced to a minimum; Considerable time saving are made; There is no contamination of the oven or the titration cell; No carry over or memory effects; Reagent consumption is greatly reduced; Water released in the carrier gas is improved as the sample actually passes through the sample directly; Low levels of moisture are determined in the trace regions coulometrically, or in the % levels volumetrically.