FAQ about Karl Fischer

Karl Fischer titration is a widely used analytical method for the determination of water content in a variety of products. We have prepared some of the most frequently asked questions and their answers to help you understand this test method better.

What is the principle of Karl Fischer?

Karl Fischer based his principle on the Bunsen reaction between iodine and sulphur dioxide in an aqueous medium. He discovered that this reaction could be modified to determine water content in a non-aqueous system containing excess of sulphur dioxide.

What is the difference between coulometric and volumetric titration?

Coulometric titration is when the titrant is generated electrochemically in the titration cell and is mainly used for water determination when the content is very low (less than 50-100 ppm) whereas in volumetric titration the titrant is added directly to the sample by a burette.

What is the Karl Fischer reagent?

The Karl Fischer reagent reacts quantitatively and selectively with water to measure water content. Here at a1 Envirosciences we offer high quality reagents for both coulometric and volumetric Karl Fischer titrations.

Coulometric Karl Fischer Reagents: For moisture analysis in organic solvents, inorganic chemicals, oil products, gases, ketones, silicone oils, lower carboxylic acids, aldehydes, aromatics, alcohols, esters, ethers, benzene, toluene, etc.

Volumetric Karl Fischer Reagents: For moisture determination in alcohols, amines, edible oils, sugar, ketones, toluene, xylene, chloroform, generator oils, insulating oils, etc.

What is important when validating a new method on my titrator?

The most important aspects to check when validating a method on your titrator are accuracy, precision, reproducibility, linearity, limits of determination, systematic errors, robustness, and ruggedness.

What is drift in Karl Fischer?

Drift is the background moisture that the Karl Fischer equipment is detecting that is not coming from your sample.

How do I know when to replace the molecular sieve in the drying tubes of my Karl Fischer titrator?

An increase in background drift can indicate that it is time to replace the molecular sieve, but you can add some blue silica gel to the top of the drying tube to serve as an indicator. When it starts showing traces of pink that also indicates it may be time to replace the molecular sieve.

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