Problems with the use of water analyzers

Attention to the use of water quality analyzer 1, the system is fully sealed. The connection of the Karl Fischer reagent fluid circuit must be fastened, from the reagent bottle to the metering pump to the reaction cell, otherwise reagent leakage will directly affect the test results. Another problem with its lack of containment is that the Karl Fischer reagent absorbs moisture from the test during the test, which can delay the titration endpoint.

2, the exact sampling problem. When the Karl Fischer reagent is calibrated, 10 mg of water must be used, and a 10-ul sampler should be used as much as possible. This will not only be accurate and fast, but also prevent the adhesion of water droplets. Similarly, the use of methanol reagents and ethyl esters have similar problems, and attention should be paid to shortening the opening time of the reaction chamber as much as possible after handling.

3, magnetic stirring speed adjustment. In the reaction tank, because the titration reagent is added locally, it is not in the same place as the electrode. Therefore, the stirring speed should be as fast as possible without forming turbulent flow. This can reach the end point as quickly as possible.

4. The titration speed should be set quickly and slowly. When titrating, try to shorten the test time as fast as possible, and strain slowly when approaching the end point, which can improve the measurement accuracy.

5. After the test is completed on the day, be sure to empty the Karl Fischer reagent in the system and clean it with methanol. Do not wash the system with water because it will not be easily volatilized. This will cause the Karl Fischer reagent to be used in the next test. Calibration is not true.

6, moisture analyzer should be away from strong magnetic fields, to avoid electronic display jitter during work, there is an abnormal phenomenon. Manual moisture analyzers, because the Karl Fischer reagent and the methanol solvent must be metered with a glass burette, and the glass burette itself must be connected to the outside world because of the equilibrium pressure.

7, the system is as close as possible. The manual moisture analyzer needs to add a U-shaped tube filled with desiccant to the suction tube and the glass burette to reduce the interference of air moisture on the test results. In the environment where the relative humidity is greater than 70%, moisture testing should not be arranged as much as possible.

8. When adjusting the titration speed of the buret, it is best to adjust to 1 drop/sec. Too fast a titration will result in a large delay error at the end of the titration, while a too slow titration will prolong the testing process. The above interference will easily lead to delay in reaching the end.