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Matters needing attention in the use of water quality analyzer

by:BOQU     2021-05-21


The following issues should be paid attention to during the use of the water quality analyzer:

1. The system is fully enclosed. The connection of the Karl Fischer reagent liquid path must be tight, from the reagent bottle to the metering pump and then to the reaction cell, otherwise the reagent leakage will directly affect the test result. Another problem of its unsealing is that the Karl Fischer reagent absorbs air moisture during the test, which will cause the titration endpoint to be delayed.

2. The accuracy of sampling. When calibrating the Karl Fischer reagent, you need to take 10mg of water, and try to use a 10ul sampler, which is not only accurate and fast but also can prevent the adhesion of water droplets. Similarly, the use of methanol reagents and ethyl esters has similar problems. After taking and placing them, care should be taken to shorten the time for opening the reaction tank as much as possible.

3. Magnetic stirring speed adjustment. In the reaction tank, because the titration reagent is added locally and not at the same place as the electrode, the stirring speed is so fast that no turbulence is formed so that the endpoint can be reached quickly.

4. The titration speed setting should be fast and then slow. The titration should be fast at first to shorten the test time as much as possible, and the strain will be slow when approaching the endpoint, which can improve the measurement accuracy.

5. After the test on the same day, the Karl Fischer reagent in the system must be drained, and then cleaned with methanol. Never use water to clean the system, because it is not easy to volatilize, which will cause the Karl-Fischer reagent in the next test. The Fischer reagent is not calibrated correctly.

6. The moisture analyzer should be far away from the strong magnetic field to avoid the electronic display beating and abnormal phenomenon when working. The manual moisture analyzer must use a glass automatic burette to measure Karl Fischer reagent and methanol solvent, and the glass burette itself must be connected to the outside because of the equilibrium pressure.

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

8. When adjusting the titration speed of the burette, adjust it to 1 drop/sec. Too fast titration speed will result in a larger delay error when reaching the endpoint; while titration speed too slow will prolong the test process, and the above-mentioned interference will easily lead to delays in reaching the endpoint.

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