The electrode is the key component of the trace moisture analyzer. The contamination of the electrode surface can directly lead to the decrease of sensitivity. Some electrodes have been used for the analysis of oil samples for a long time. After the electrode surface is contaminated by oil, the sensitivity decreases, which makes the judgment of the end point of the electrode slow. Causes the Karl Fischer reagent to be excessive, and the color of the solution is darker at the end point reaction. At this time, the electrode must be cleaned. In addition to this method, some measures can be taken.
Although contamination on the electrodes is not visible to the naked eye, a slow response can be observed that directly affects measurement accuracy. Therefore, the electrode must be cleaned after a period of use, but a considerable number of operators have not considered this problem. When the sensitivity is reduced and the electrode is seriously contaminated. You can wipe the electrode with a little acetone on paper, wait for the acetone to evaporate completely before use, or immerse the electrode in dilute nitric acid solution for 24 hours, then take it out, rinse it with water, wipe the filter paper, or wash it with potassium dichromate solution for 1 minute to activate the electrodes.
In special cases, such as the sample is waiting to be analyzed, the cleaning time of the electrode is not allowed. At this time, an emergency solution can be used to solve the event of electrode contamination. Gently rub both ends of the electrode with very fine sandpaper, after the filter paper is wiped clean, it will be effective. If the instrument is not used for a period of time, all Karl-Fischer reagents in the pump tube and the liquid circuit should be drained to avoid clogging the pipeline due to crystallization caused by the volatilization of the reagent.
Similarly, the Karl-Fischer reagent in the reaction bottle should also be drained, and the electrode should be wiped clean. In the testing of the instrument, it can often be found that the operator's sample measurement is over, and the power supply has been shut down. The maintenance of the instrument and the accuracy of the measurement should be closely related to the lack of awareness.