Trace moisture analyzer detection principle

Trace moisture analyzer uses Karl-Fischer Coulomb titration detection principle, the application of microcomputer automatic control technology, the use of large-screen LCD display, full Chinese menu prompt operation, a wealth of calculations, print experimental results, is oil, chemical, power Ideal instrument for testing moisture content in medicine, pesticides, and research institutes.

Shanghai Yi Hong Electric Technology Co., Ltd. production of trace moisture analyzer LCD large-screen display, automatic control 0 ~ 400mA electrolytic current, measuring range between 5ug ~ 100mgH2O.

The Karl Fischer method, which is called the Fischer method, is the volumetric separation method for measuring moisture content proposed by Karl Fischer in 1935. The Fischer method is the most specific and accurate method for determining water in various types of chemical methods. Although it is a classical method, it has been improved in recent years, improving accuracy and expanding the measurement range. It has been listed as a standard method for determination of moisture in many substances.

The Fischer-Tropsch method is an iodometric method. The basic principle is the use of iodine to oxidize sulphur dioxide, requiring - quantitative water to participate in the reaction: I2SO2 2H2O-2HI H2SO4

The above reaction is reversible. When the concentration reaches more than 0.05%, the reverse reaction can occur. If we allow the reaction to proceed in a positive direction, it is necessary to add an appropriate alkaline substance to neutralize the acid generated during the reaction. Experiments have shown that pyridine is added to the system so that the reaction proceeds rightwards. Experiments have shown that pyridine is the most suitable reagent, while pyridine also has the ability to combine with iodine and sulfur dioxide to reduce the vapor pressure of both. Therefore, the reagent must be added to methanol or another solvent containing active OH groups to convert the anhydride pyridine to a stable methyl* hydropyridine.

The Karl Fischer moisture method is a method of measuring the moisture content of a sample using methanol as the titrant. This method is simple, high accuracy, widely used in medicine, petroleum, chemicals, pesticides, dyes, food and other fields. It is especially suitable for samples that are easily destroyed by heat, not only free water but also bound water can be measured, and is often used as a standard method for analysis of moisture, especially trace moisture. However, it is not suitable for samples containing strong reducing substances such as VC.

Karl Fischer reagent is a reagent for the determination of trace moisture in certain substances. Its components are: methanol, pyridine, iodine, and sulfur dioxide. There are two methods for determining the end point: visual and potentiometric methods.

The main components are I2, SO2, C5H5N. The basic principle of the CH3OH Karl Fischer method is that when I2 oxidizes SO2, quantitative H2O is required.

I2 SO2 2H2O=2HI H2SO4

This reaction is a reversible reaction. To carry out the reaction in a forward direction, it is necessary to add an appropriate basic substance to neutralize the acid produced by the reaction. Pyridinium (C5H5N) can meet this requirement, and adding methanol can avoid the occurrence of side reactions.

The Karl Fischer reagent is brown due to the presence of I2. When I2, SO2, and H2O react, I2 browns fade.

This method appears in brown as the endpoint of the titration.

The Karl Fischer method is a non-aqueous titration method. All containers need to be dry. If 1 g of Karl Fischer reagent is mixed with 6 g of water during the preparation and storage, the reagent will fail.

Karl Fischer reagent is a reagent for the determination of trace moisture in organic matter. It is also called water reagent, also known as Carrageen's reagent. The initial water reagent is mainly prepared from iodine, sulfur dioxide, methanol and pyridine in a certain proportion. This reagent has bad odor and great toxicity, poor stability, shelf life within three months, and does not apply to the determination of aldehydes, ketones, organic substances, the user brings the storage, the use of inconvenience. With the advent of the Automated Carrie Analyzer, the requirements for the Carter's reagent have also been increased. Therefore, people have developed various types of water reagents. Because of the type of water reagents, the methods are different. When using them, it is necessary to look at the detailed descriptions of the manufacturers.