Page 466 - Applied Pharmacognosy

oxidation of iodide from solution and the endpoint is
detected electrochemically. Coulometric determination is
best suited for samples with less than 1% of water.

• When used correctly, the test is capable of measuring water

levels as low as 1 ppm or 0.0001 percent.

• The amount of water in the sample is calculated by
measuring the current needed for the electrochemical
generation of iodine (I2) from iodide (I–) solution.

• Precautions:

• The reagent should be standardized before use.