Karl Fischer Moisture Analyzer Solution to "Over-titration Endpoint"
When the Karl Fischer moisture analyzer (also known as: insulating oil micro-water measuring instrument, moisture analyzer) has a titration failure, in addition to being unable to reach an equilibrium state and perform normal analysis, the color of the Karl Fischer reagent in the titration tank will also change. Visible anomalies appear (balance points are darker).
Common causes of overtitration failures in Karl Fischer moisture analyzers
1. After the instrument is used, only the power of the stirrer is turned off, but the instrument switch is not turned off, so that the generating electrode is still in working condition, and excess iodine is electrolyzed from the reagent, which exceeds the equilibrium state of the instrument.
2. The stirring speed is too low, and the elemental iodine produced by electrolysis is not mixed in time. (Different manufacturers and models of reagent formulations, different reagent viscosity, density)
problem solving
After a problem is found, do not pour out the Karl Fischer reagent in the instrument and replace it immediately.
1. Turn on the power of the stirrer and let the excess iodine stir evenly in the titration pool. Increase the rotation speed (choose the appropriate stirring speed, the speed will affect the use of reagents)
2. Use a micro-syringe to extract ultrapure water, and then add an appropriate amount of ultrapure water to the instrument, the color of the reagent will gradually become lighter, until it passes the water state. Start electrolysis to rebalance and proceed with analysis as normal.
