Validation shows that the procedure is precise and accurate. It was invented in 1935 by the german chemist karl fischer. In most cases, the buffering of the reaction medium by the karl fischer reagent used will be sufficient. Determination of water content according to karl fischer direct. Pdf karl fischer titration usage and uncertainty evaluation. The karl fischer reaction uses a coulometric titration to determine the amount of water in a sample. Titration excellence t9 konnen sie verschiedene analysen gleichzeitig an demselben instrument durchfuhren.
Karl fischer titration is a widely used analytical method for quantifying water content in a variety of products. Modern instruments, such as the aquamax kf, apply the coulometric principle, whereby the water present in the sample is coulometrically titrated to a predefined endpoint at which free iodine exceeds a minute. Karl fischer volumetric titration theory and practice igz instruments. Karl fischer titration of h 2o detecting trace amount of water in organic solution. Karl fischer titration, karl fischer method, coulometric. Redox titration redox titration is based on the redox reaction oxidationreduction between analyte and titrant. Pdf the volumetric karl fischer titration is concerned with the water determination from 15 % up to 100% content in the most different samples such. This catalogue features a wide choice of electrodes for every applica tion and budg et. The karl fischer titration is used in many different ways following its publication in 1935 and further applications are continually being explored.
In acidbase titration, the neutralization point occurs at a ph of 7. The principle of the test consists in reaction of any water present in a test. Liquid samples can be analyzed by direct injection of the. Today, the titration is done with an automated karl fischer titrator.
At the end of the titration, the display will show the result in % of water content. Mechanism and reaction rate of the karl fischer titration. Kf volumetric titrator for karl fischer titrations. Karl fisher titration is a technique for the determination of moisture content. Thanks to its design and its titration algorithm, the tim550 volumetric karl fischer titrator provides accurate results and clear sample information.
Titration excellence means a twoinone instrument and offers the utmost. Karlfischer titration the method for determining water quite some experienced analyst will be unpleasantly reminded by the pyridine smell, when hearing the name karl fischer. Pdf volumetric karl fischer titration researchgate. Published a method in 1935 to determine trace amounts of water in samples. Titration theory and practice choosing the right reagent and medium the choice is made on the basis of laboratory conventions and standard methods. Pdf in 1935, karl fischer kf proposed a titration method for water content determination. Kf the water determination test karl fischer method is designed to determine water content in substances, utilizing the quantitative reaction of water with iodine and. A practical alternative to karl fischer titration for. Volumetric karl fischer titration kft is a widely used measure of moisture content.
Karl fischer titration quantitative determination of water kf reagent reacts quantitatively and selectively with water reagent for kf titration needs. Laboratory solutions from mettler toledo 2,740 views. Kf or kft it remains the primary method of water content determination used worldwide by. Karl fischer volumetric titration theory and practice.
The fundamental principle behind it is based on the bunsen reaction between iodine and sulfur dioxide in an aqueous medium. The coulometric karl fischer titration is concerned with the determination of traces of water from e. Coulometric titration is mainly employed for low water content determination according to the karl fischer titration technique. Buffer solutions for volumetric karl fischer titration. When compared to a routine ftir method, the karl fischer.
Looking back on half a century of experience in karl fischer titration, metrohm has shaped what coulometric and volumetric water analysis are today. Litmus is a good indicator for an acidbase titration, because it changes color at a ph of around 6. It is based on a chemical reaction between 5 components. Analytica chimica acta, 94 1977 395 403 eisevier scientiric publishing company, amsterdam printed in the netherlands mechanism and reaction rate of the karl fischer titration reaction part v. Determination of water content according to karl fischer direct method. Karl fischer titration basics what is karl fischer titration. With some samples, however, such as strong bases or acids, the ph is shifted into the acid or alkaline. The karl fischer titration is a titration method for measuring water content in basically all types of substances. Karl fischer published a reagent for water determination consisting of iodine, so2, pyridine. It was invented by a german chemist by name karl fischer in the. Karl fischer titration, karl fischer aquametry, moisture content determination, water content determination. Karl fischer titration determination of water eugen. The bunsen reaction between iodine and sulfur dioxide in an aqueous system is the basis for the karl fischer reagents reactions. The fluidscan is a handheld device that offers a practical solution for maintaining the key parameters of a healthy lubrication system.
The titration is conducted coulometrically, where the reagent is generated in the reaction cell via electric current. Redox titration university of massachusetts boston. The karl fischer titration is merely a means of measuring sample water content. Repeat the same procedure by resetting the instrument to obtain 3 values of water content having not more. Bruce is the application scientist for karl fischer titration within the instrumental analytics team. Karl fischer reagents for volumetric water determination kf instrument should not be set up in areas that are subject to large temp fluctuations, high humidity. Karl fischer titrators for water moisture determination.
Karl fischer titration reagents and applications reagents for karl fischer titration are available in a broad range, depending on a purpose and ecological awareness of the user. History of karl fischer titration karl fischer march 24, 1901 april 16, 1958 was a german chemist published a method in 1935 to determine trace amounts of water in samples. Karl fischer titration,principle,apparatus, titration. An uncertainty calculation plugin allowing all the measurement parameters to be taken into account is also available. The method is used in many astm methods, 14 nist srms, and testing labs that run 24 hours a day, seven days a week. Basic theory of karl fischer titration laboratory talk. What is karl fischer titration and what are its applications. They must not be placed in the proximity of heating, cooling devices. Karl fischer titration is the method of choice for water content determination. Karl fischer titration is a classic titration method in chemical analysis that uses coulometric or volumetric titration to determine trace amounts of water in a sample. Water determination by karl fischer titration labicom. It can determine concentrations of water on the order of milligrams per liter. With more than 11 years experience in qc and product development business, he is very familiar with the. Fluidscan to provide a practical alternative to karl fischer titration.
Karl fischer titration,principle,apparatus, titration types,endpoint detection 1. Karl fischer titration is a titration method which uses volumetric or coulometric titration to determine the trace quantity of water in the sample. Jarubol chaichana bureau of drug and narcotic department. The amounts of water generally determined via coulometric karl fischer. In the volumetric titration method, iodine required for reaction with water is previously dissolved in water determination, and water content is. History of karl fischer titration the milestones 1980 changed the world of kf titration 8 1935 karl fischer published a reagent for water determination consisting of iodine, so2, pyridine and methanol. Karl fischer titration titration method in analytical chemistry that uses coulometric or volumetric titration to. The electrometric method, whether by direct titration or backtitration, is the more accurate one and for this reason recommended.
At the present time we are experiencing another phase of. With titration excellence t9 you are able to execute different analysis in parallel on the same instrument. Typical relative standard deviation of the procedure is 12%. Karl fischer moisture determination in difficult samples for water content determinations using the karl fischer method on solids that are either insoluble, react with the karl fischer reagent or. Fill and rinse the burette karl fischer volumetric titrator duration. The kf instrument was designed to be used with hach s karl fischer moisture content application pack hach pn ap0014. In contrast to gravimetry, no sparingly soluble compounds.
707 594 100 1491 838 699 66 266 436 456 453 728 911 1269 742 1531 319 407 862 1001 1329 1085 1106 267 493 1158 1519 311 1072 388 771 482 231 715 783 453 1413 1141 1220 1452