The detection principle of a trace moisture analyzer
The micro moisture analyzer adopts computer automatic control technology, adopts a large screen LCD display screen, full Chinese menu prompt operation, rich calculation, and printing experimental results function. It is a weighing instrument for testing moisture content in the petroleum, chemical, power, pharmaceutical, pesticide industries, and scientific research institutions. The Karl Fischer method, also known as the Fischer method, is a capacity partitioning method for measuring moisture proposed by Karl Fischer in 1935. The Fischer method is the most specific and accurate method among various chemical methods for determining the moisture content of substances.
The classic method has been improved in recent years, improving accuracy and expanding the measurement range, and has been listed as a standard method for determining moisture in many substances. The Fischer method belongs to the iodometric method, and its basic principle is that when using iodine to oxidize sulfur dioxide, a certain amount of water is required to participate in the reaction: I2SO22H2O-2HIH2SO4 The above reaction is reversible. When the concentration reaches above 0.05%, a reverse reaction can occur. If we want the reaction to proceed in a positive direction, we need to add appropriate alkaline substances to neutralize the acid generated during the reaction process. It has been experimentally proven that adding pyridine to the system can cause the reaction to proceed to the right.
Especially suitable for samples that are easily damaged by heat, it can not only measure free water but also bound water, and is often used as a standard analysis method for moisture, especially trace moisture. But it is not suitable for samples containing strong reducing substances such as VC. Karl Fischer reagent is a reagent used to determine trace amounts of water in certain substances, consisting of methanol, pyridine, iodine, and sulfur dioxide. There are two methods for determining the endpoint: visual inspection and potential method.
Factors to consider when selecting a moisture analyzer
The minimum difference that can be read on the resolution or display screen. This is also known as readability or readability.
Repeatability - The ability of a moisture balance to display the same results when repeatedly testing the same sample. Represented as standard deviation.
An important function for conducting moisture analysis. These are based on the characteristics of the analyzed product, such as those that require special heating curves.
Special functions, such as testing products with extremely low moisture content, providing graphical display of moisture content changes, and establishing a frequently executed test library.
