Various Applications of Karl Fischer Moisture Meter
It operates on solids, liquids, fuels, biomass, food, plants, soil, or almost any substance you can think of, and the importance of knowing water content can range from useful information to important information. The two most widely used methods today are
The drying method for weighing samples is to weigh, heat for a specific time, and then reweigh to determine the loss.
Titration method, specifically for measuring water in samples.
1. The drying method is both simple and economical, as all that is required is a balance, calibrated oven, and timer. They may be suitable for solids with water as the only volatile component, or they can be easily released by heating. Unfortunately, these methods have several drawbacks:
The measured material is not only water, but also volatile enough to be expelled by time and temperature.
Heating the sample to dryness can cause the sample itself to decompose/oxidize, thereby altering the apparent moisture content.
The losses caused by drying may take several hours to complete, so the turnover time is quite slow.
Not suitable for most liquids.
2. The titration method (Karl Fischer moisture analyzer analysis) is very specific, in fact, it directly measures the moisture in the sample. There are many advantages:
The measured values are only water, both bound and free.
Concentration range (ppm to 100%).
The results are accurate and reproducible.
A typical titration only takes a few minutes, and if needed, the turnover can be completed very quickly.
Titration is the preferred method for most liquids (i.e. the only method).
Karl Fischer's simplified chemical reaction involves introducing free iodine into cells along with the sample. And stoichiometric binding with water to a certain endpoint.
The volumetric titration method uses an accurate titration method to titrate the dispensed iodine reagent.
Coulomb titration generates free iodine from the electrolyte of the battery itself.
Most matrix problems (i.e. side reactions, solubility) of solid or liquid samples can be solved through appropriate sample preparation and/or processing, and it is important to understand the sample matrix as much as possible to produce good results.
The correct sampling technique plays a crucial role in the correlation of results:
1. The sample container must be completely dry, as any moisture will contaminate the sample.
2. The material must be sufficiently uniform to obtain the sample.
3. The actual sample transfer to the container must be completed as soon as possible to maintain a pollution-free moisture content.
4. Moisture in the atmosphere can be a major source of pollution, especially for ppm level samples, after all, moisture is everywhere in the air!
