Is the pointer of the moisture analysis electrode moving to the right?
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The moisture content of a solution obtained from a process carried out recently was measured using a KF-1 moisture meter. Since the sample to be tested was black, it was possible to observe only the pointer of the electrode; after adding the sample, the pointer shifted to the right. Is such a result free of water, or are there factors affecting the measurement?
You should provide a brief description of your sample, that is, the components of the so-called solution sent along with the process details, so that other users can determine the issue. The more detailed the description of the problem, the easier it is to clarify it. If it’s confidential, it’s best not to post a question.
The components are roughly tetrachloroethane, pentachloroethane, hexachloroethane, and dichloroethylene. Does free chlorine affect the results?
These chlorinated hydrocarbons may produce free chlorine or phosgene through photolysis or pyrolysis, causing the iodide ions in the Carr’s reagent to be oxidized to iodine and resulting in a false endpoint. Add fine powder of anhydrous sodium sulfite to the sample and shake it for a while, or add a small amount of reduced iron powder and shake it for a while; then let it stand before measuring the water content.
We added 1,14-diene, but it had no effect
It can be determined through process analysis whether the sample is free of water. As for the indicator, it measures the weak polarization current of the I2/I- electrode pair in the solution; once the titration is complete, any slight excess of I2 will cause the polarization current to increase and remain at that level. Pointer deflection indicates the presence of moisture or gas interference; analyze it on your own.