For samples with a water content greater than 0.1%. The amount of water is determined by volumetry, based on a redox reaction (Iodine/Iodide) sensitive to very low moisture levels.
Volumetric determination
The amount of iodine consumed in the titration is proportional to the water content of the sample. The end point is detected by a double platinum polarized electrode.
In presence of a base and a solvent (i.e. imidazole and methanol)
I2 + SO2 + 2H2O ➝ 2HI + H2SO4
The amount of iodine consumed in the titration is proportional to the water content of the sample. The end point is detected by a double platinum polarized electrode.
There are two ways to perform this reaction: with one component reagents or with two components.
One component reagents
All the necessary reagents to perform the reaction (iodine, sulphur dioxide and imidazole) are present in the titrant reagent: AQUAMETRIC® Composite.
The media generally used with these reagents is dry methanol.
Main advantages:
- Easy to use: All in one
- Flexibility to select the appropriate solvent (as media) to extract the water from the sample
Two component reagents
The reagents to perform the reaction are separate in two components:
- AQUAMETRIC® Titrant: Contains iodine dissolved in methanol
- AQUAMETRIC® Solvent: Media that contains the rest of necessary compounds (imidazole and sulphur dioxide in methanol)
Main advantages:
- High stability and shelf life
- Faster titration and high accuracy