How to choose a moisture analyzer

How to choose a moisture analyzer

At present, moisture analyzers are divided into chemical moisture analyzers (Karl Fischer moisture analyzers) and physical moisture analyzers (infrared moisture analyzers). Karl Fischer moisture analyzer is further divided into Karl Fischer volume method and Karl Fischer coulomb method; infrared moisture analyzer is further divided into infrared incandescent lamp moisture analyzer and halogen ring lamp moisture analyzer.

Chemical moisture analyzer:

Karl Fischer water measurement method is suitable for the determination of water content in many inorganic compounds and organic compounds. It can be divided into two methods: Karl Fischer volumetric method and Coulomb method; the biggest difference between the two methods is the source of I2. I2 in the volumetric method It comes from the titration reagent, and I2 in the coulometric method is produced by electrolysis of the electrolyte containing I- ions. The amount of electricity passing through the electrolytic cell has a strict quantitative relationship with the amount of I, so the coulometric method has higher measurement accuracy. The speed and analysis process are faster and more accurate than the volumetric method.

Karl Fischer volumetric method uses volumetric Karl Fischer reagent as the standard solution. When the Karl Fischer reagent comes into contact with the sample, it will react quantitatively with the water in the sample. Calculate the water content of the sample by consuming the volume of the standard solution.

Karl Fischer Coulomb method is the Karl Fischer reaction in which iodine is directly produced by the electrolytic electrode. The water content of the sample is calculated using the quantitative relationship between the amount of electricity required for electrolysis of iodine and iodine; the coulometric method is an absolute determination without measuring the titer.

Physical moisture analyzer:

Physical moisture analyzers include infrared moisture analyzers, microwave moisture analyzers, halogen moisture analyzers, etc. The main component is the load cell. The term of the load cell is the heart of the moisture analyzer. The accuracy of the load cell is directly related to the measurement of the moisture analyzer. stability and accuracy.

It is an infrared moisture meter that is very similar to the "drying loss method" of the recognized standard measurement method of the infrared moisture analyzer standard. It is also called the "drying loss method" of the recognized standard measurement method • 5 hours method), (135°C • 3 hours method), etc., by placing the sample in a dryer for a long time of heating and drying, to accurately measure the mass change before and after drying, and calculate the moisture content. .

The microwave moisture analyzer uses microwave field to dry samples, which accelerates the drying process. It has the characteristics of short measurement time, convenient operation, high accuracy and wide application range. It is suitable for granular, Moisture determination in powdery and viscous solid samples.