Precautions for trace moisture analyzer
The trace moisture analyzer is a device that uses Karl Fischer reagent as the titration solution to determine the moisture in the sample by the coulometric method. Now it is using its advantages of convenient, fast and high precision. Auxiliary agents, fine chemicals, power oil in the power industry, medicine, pesticides, agricultural products, scientific research, colleges and universities, etc. have been widely used. The samples to be analyzed are also various, including liquid and paste (such as ethanol, methanol, transformer oil, steam turbine oil, resin, emerging industries such as electrolytes in lithium batteries, etc.), and powder. , Granular (such as raw material plastic particles of PVC pipes, etc.), gas, etc. It can be said that as long as it requires moisture content, it needs to be measured. In the actual use process, what should we pay attention to to improve the stability of the trace moisture analyzer and the accuracy and reproducibility of the results?
(1). Precautions for use environment
1. The humidity of the use environment should be kept within a reasonable range, and the electrolyte should be avoided as much as possible. After the electrolyte gets wet, the blank current will increase and it will not be easy to reach the equilibrium point. The test results are unstable and the data will fluctuate.
2. The temperature of the working environment should be within a reasonable range. Avoid low or high temperature. Excessive temperature (above 35 degrees) will increase the conductivity of the electrolyte and cause high test data. If the temperature is too low (below 0 degrees), the conductivity of the electrolyte will decrease, and the test data will be low.
3. Avoid direct sunlight, direct sunlight will cause photosynthetic reaction of the reagent, the reagent will automatically pass iodine. Trace amounts of iodine will cause low data.
(2). Precautions for sampling operation
1. The typical measurement range of the card coulometric method (electricity method) is 10μg ~ 10mg. In order to obtain accurate measurement results, the sample injection volume should be appropriately controlled according to the water content of the sample.
2. Make sure that the injector used is dry before injecting a sample. Each sample has a dedicated injector. If multiple samples share one injector,
3. Before injecting the sample, be sure to wipe the needle part of the sample gas from the end to the front with filter paper to prevent the water attached to the needle from being brought into the reagent or adhering to the sample pad. Inaccurate test results.
4. When injecting the sample, press the start button to inject the sample into the reagent as quickly as possible.
5. When injecting the sample into the electrolytic cell, the needle of the liquid sampler should be inserted into the electrolyte, and the liquid, solid, gas sampler and sample should not contact the inner wall of the titration cell and the electrode.
6. To ensure the consistency of each injection volume. The better the consistency, the better the data repeatability.
(3) Precautions when the reagent is unstable
1. The reagent is not easy to reach the end point during use due to high air humidity, frequent sample preparation or solid sample, which is the most common problem in the experiment. If the reagent is not easy to reach the end point when making solid samples due to high air humidity, shaking the electrolytic cell can be adopted to absorb the moisture in the internal space of the electrolytic cell, so that it can reach the end point faster.
2. Reagents are not easy to reach the end point when the sample is frequent or the reagent is close to failure. You can adjust the sensitivity of the reagent by injecting appropriate amount of pure water to make it reach the end point faster.
3. After the reagent is used for a long time, the iodine consumption in the reagent is too much and the reagent is not easy to reach the end point when it fails. At this time, the new reagent should be replaced as soon as possible. If there is no new reagent and the test sample is urgently needed, you can temporarily inject appropriate amount of pure water to adjust the sensitivity of the reagent and make it reach the end point. The measured result at this time can only be used as a reference.
From: http: //
Valve Bag,Outer Valve Bag,Bulk Bag Valve,Block Bottom Outer Valve Bag
ZHEJIANG IMERIC ENVIRONMENTAL PROTECTION SCIENCE & TECHNOLOGY CO., LTD. , https://www.imeric-valvebags.com