Measuring moisture with a Karl Fischer titrator
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Dear experts, I would like to ask whether the titration cell should be kept yellow when using the Mettler Toledo 916T~touch moisture meter to measure moisture content Today, while testing the moisture content of methanol, the solution in the titration cell was brown at first, and the moisture content of methanol was found to be 1300 ppm. Later, the solution in the titration cell was drained to allow it to reach equilibrium again. Testing the moisture level at this point yielded a result of 900 ppm. I want to ask why there is such a big difference?
The reagents and the low moisture content have not reached complete equilibrium
The balance has been achieved; the instrument indicates a balanced state
Hehe, then have fun!~~~~
That’s because a titration phenomenon occurred
Just drain the solution from the titration cell, or add some pure water to it.
It’s just that there’s too much titrant; when there’s an excess, it turns brown. In my opinion, it still requires the expertise of an expert
If the Coulomb method or Karl Fischer reagent is used, when the solution is brown, it indicates that the solution has not reached the equilibrium point; in such a case, sampling is carried out directly, and the resulting measurement values will naturally be inaccurate.