Titration assembly, coulometric

A number of coulometric titrators are available commercially and are simple to operate. Suitable apparatus can also be assembled from readily available equipment. The essential requirements are ... 

The critical datum is not a buret reading, as it was in the case of the volumetric method. Rather, the amount of iodine used is determined coulometrically by computing the coulombs (total current over time) needed to reach the end point. The coulombs are calculated by multiplying the current applied to the anode-cathode assembly (a constant value) by the total time (seconds) required to reach the end point. The modern coulometric titrator automatically computes the amount of moisture from these data and displays it. 

Coulometric titrators are available from several manufacturers. In addition, they can be assembled easily from components available in most analytical laboratories. Figure 24-7 is a conceptual diagram of a coulometric titration apparatus showing its main com-... 

Presently there is available on the market commercial Karl Fischer titration assemblies, some of which automatically stop the titration at the end point Instructions for operation of these devices are provided by the manufacturer and not described herein. This test method is not intended for use with coulometric Karl Fischer titrators. 

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