HYDRANAL Coulomat AF 7 for coulometer AF7, Glass Bottle, 1 L

Coulometric Karl Fischer titrations traditionally require two reagent solutions: an anolyte (solution in the anode compartment) and a catholyte (solution in the cathode compartment). Hydranal-Coulomat A-type or E-type reagents are used as anolytes. The anolytes contain iodide and a sulphur dioxide/imidazole buffer in suitable solvent systems. Hydranal-Coulomat CG reagents are used as catholytes. Coulometric reagents based on different solvent compositions serve the diverse requirements of samples to be analyzed. Hydranal-Coulomat Oil contains methanol, xylene and chloroform and thus supports titration in oils and non-polar samples. The methanol-free Hydranal-Coulomat AK is suitable for suppressing side reactions during the titration of ketones. Special working techniques are also supported by special reagents, e.g. the use of the Karl Fischer oven with Hydranal-Coulomat AG-Oven or the use of a cell without a diaphragm with Hydranal-Coulomat AD.
Coulometric cells
There are two different types of coulometric cells, with and without a diaphragm. The diaphragm separates the anode compartment from the cathode compartment. The oxidation of I to I² takes place at the anode, while the reduction of protons to H² takes place at the cathode. In cells without a diaphragm, the anode and cathode compartments are not separated and only one reagent, the anolyte, is required. Although the use of such a cell seems simpler, the cell with a diaphragm achieves the highest accuracy, especially in the absolute trace range or when using special reagents.
Advantages of HYDRANAL coulometric reagents:

• Easy to use
• High accuracy for water in the trace range
• Stable conditions in the titration cell
• Many special reagents
• Long shelf life (up to five years)