WKT-A2 "Starter" automatic Karl Fischer micro moisture analyzer uses the principle of Karl Fischer Coulometric method (electricity method) to quickly determine the trace amount of water in the sample, determine the water as low as 1ppm, can be measured in 1 minute A trace amount of moisture in solids, liquids, and powders. Friendly man-machine interface, 240*64 blue screen LCD display, full Chinese menu, detection circuit adopts digital processing technology, which overcomes the interference of temperature drift and power supply voltage fluctuation of traditional instruments on the test process, and improves the accuracy and sensitivity of the test. The whole machine adopts the relayless process design, which eliminates the hidden danger caused by the oxidation of the contact of the memory relay and prolongs the service life of the instrument. The instrument has built-in various calculation formulas, which can directly display the % and ppm moisture of the sample, and has a printing interface. It can be equipped with a micro printer, which is widely used in the chemical, petroleum, pharmaceutical, electric power, food, scientific research, testing and other industries.

WKT-A2"Economic" Automatic Karl Fischer Trace Moisture Analyzer principle:

1, Moisture reaction

Karl Fischer's moisture measurement works by using iodine to oxidize sulphur dioxide, which requires a certain amount of water to participate in the reaction: I2+S02+2H2Ｏ=2HI+H2SO4, this reaction is reversible. In order to move the reaction in the positive direction and to quantify it, an alkaline substance must be added. Therefore, the reagent must be added with methanol or another solvent containing an active OH group to convert the thioacetate pyridine into a stable pyridine bisulfate. The total reaction formula is:

In the 'KF' coulometric titration method, electrolysis electrochemical electrolysis directly produces the desired iodine. Using a strict quantitative relationship between charge and iodine, the calculated water content is measured. When there is a small amount of free iodine, 'Pt' indicates that the voltage difference across the electrode drops sharply, and the change is used to determine the end point of the titration.

2, Electrolysis reaction (Faraday's law of electrolysis)

During the electrolysis process, the electrode reaction is as follows:

Anode: 2I--2e→I2

Cathode: I2+2e→2I-, 2H++2e→H2↑

It can be seen from the above reaction that 1mol of water is required to oxidize 1mol of sulfur dioxide by 1mol of iodine. Therefore, the equivalent reaction of 1mol of iodine with 1mol of water requires 2 x 96493C of electricity (Faraday constant 9.6493 x 10000 C/mol) for electrolysis of 1mol of iodine, and the mass of 1mol of iodine-depletable water is 18g.

Available from Faraday's law of electrolysis, in the formula: W - the moisture content in the sample (μg); Q - the amount of electricity (mC); 18 - the molecular weight of water.