WKT-A3 "Prospect" 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, measuring the water as low as 0.001ppm, it can measure the trace moisture of solid, liquid and powder in 1 minute. The instrument comes with printing function, can store 200 sets of data, can be inquired and printed in real time, the print data meets all the operations, formulas, calculations, reports and other contents in many national standards! 5.7-inch (320*240mm) LCD large screen, friendly man-machine interface, button-type design, fault self-test, automatic interference deduction, reagent life reminder and other functions are designed to be classic, convenient and simple. WKT-A3 meets a number of national and international moisture measurement standards, and has eight water calculation formulas. The six measurement methods can be used in various industries for moisture measurement. They are widely used in chemical, petroleum, pharmaceutical, electric power, food, scientific research, testing and other industries.

WKT-A3 Karl Fischer micro 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 1 mol of water is required to oxidize 1 mol of sulfur dioxide by 1 mol of iodine. Therefore, the equivalent reaction of 1 mol of iodine with 1 mol of water requires 2 x 96493C of electricity (Faraday constant 9.6493 x 10000 C/mol) for electrolysis of 1 mol of iodine, and the mass of 1 mol 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.