Which KF method is right for low-volume samples?

There is no general answer to this question. The optimal KF method depends on the water content of the sample and not on the sample size. Read our blog article to learn more about this topic: Blog: Karl Fischer titration – When to use volumetry or coulometry

Can I analyze the coulometric bromine index according to ASTM D1492-08?

Yes, the OMNIS Coulometer allows coulometric bromine index determinations according to ASTM D1492-08. See OMNIS Coulometer

What is a Karl Fischer titrator?

Karl Fischer (KF) titrators are used for measuring both free and bound water content. With the KF method, you can, for instance, determine the surface water on crystals as well as the water contained within the crystals. KF titrators can be used for moisture determination (i.e., water content determination) in all sample types: liquids, solids, slurries, and gases KF titrators are applied over a wide concentration range from ppm up to 100% KF titrators are fast and highly selective KF titrators supply reproducible and correct results

What is the difference between volumetric and coulometric Karl Fischer titration?

The table below compares volumetric KF titration (volumetry) to coulometric KF titration (coulometry). Volumetric KF titration Coulometric KF titration Moisture 0.1% to 100% 0.001% to 1% Sample addition solid or pasty samples can be added directly into the titration vessel (opening a volumetric titration cell for a short period of time does not falsify the results) liquid samples are added with syringe through a septum liquids or gases are added with syringe through a septum: to avoid ambient humidity to enter the titration cell, never open a coulometric cell Titer determination regularly not necessary lodine addition/generation iodine-containing titrant is added via buret produced by a generator electrode by anodic oxidation Learn more in our blog article: Blog: Karl Fischer titration – When to use volumetry or coulometry

What kind of support and training does Metrohm offer after purchase?

Metrohm is present in over 80 countries to ensure local training and support. Metrohm offers: On-site installation and training Application support from our global network of experts Webinars, tutorials, and documentation Service contracts for preventive maintenance and calibration

What should I consider when choosing a Karl Fischer titrator?

When selecting a KF titrator, consider: Water content range: Use coulometry for trace levels (ppm) and volumetry for higher concentrations. Sample type: Liquids, solids, or gases may require different accessories (e.g., oven method for solids). Throughput: For high sample volumes, automation (e.g., OMNIS Sample Robot) boosts efficiency. Compliance needs: Ensure the system supports GMP/GLP, 21 CFR Part 11, and pharmacopeia standards. Modularity: Metrohm’s OMNIS platform grows with your lab – start small and expand as needed. Our Karl Fischer experts are happy to assist you with your questions: Contact us

Karl Fischer titration

Q: How can I measure solids with low water content with Karl Fischer titration?

Low levels of water are analyzed best with a Coulometer . The coulometric method is very sensitive. Therefore, we do not recommend opening the titration cell to add a solid sample. Atmospheric moisture would falsify the results. The oven method is the optimal solution for solids with low water content. Learn more about the oven method in our blog and application bulletin: Blog: Oven method for sample preparation in Karl Fischer titration Application Bulletin: Automatic Karl Fischer water content determination with the 874 Oven Sample Processor Watch the following video to see the OMNIS Coulometer and OMNIS Sample Robot Oven in action.

Q: What equipment is needed to perform Karl Fischer titrations?

To carry out volumetric titrations , you need a KF titrator with a completely equipped titration vessel, indicator electrode, dosing unit, and suitable reagents for volumetric KF titration. For coulometric titrations , you need a coulometer, with a completely equipped titration cell, indicator electrode, a generator electrode with or without diaphragm, and a reagent suitable for coulometric KF titrations.

KF titrators and accessories for volumetric and coulometric water content determination in liquid, solid, or gaseous samples.

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Whatever your requirements – we have the right Karl Fischer titrator for you

Our portfolio of Karl Fischer titrators includes compact all-in-one options for routine moisture determination as well as fully automated Karl Fischer systems for volumetric and coulometric Karl Fischer titration of water contents from 0.001 to 100%. Use the filters to refine your search and find the perfect Karl Fischer titrator for you. Are you looking for potentiometric titrators? Go to our potentiometric titrators

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OMNIS Titrator for Karl Fischer titrations, close-up of titration cell

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Karl Fischer titration – Online courses

Learn Karl Fischer at your own pace, on your schedule. Our online courses are designed to help both new and experienced Metrohm users get comfortable with their instruments and start generating reliable results quickly.

Designed for a watch-and-try approach, our courses are most effective when viewed alongside your instrument, allowing you to immediately apply the techniques demonstrated and reinforce your understanding.

Start learning today

Reliable and accurate measurements – Components for your KF titrator

Electrodes

Use the Electrode Finder to search for the electrode you need: double Pt indicator electrode for volumetry or coulometry or generator electrode with or without diaphragm.

Accessories

Use the Accessory Finder to search for individual titration vessel lids, stoppers, seals, and more or pre-configured accessory sets containing all accessories you need in one package.

Software

Increase the efficiency and productivity of your lab with OMNIS Software. This modern lab data management software complies with 21 CFR Part 11 and EudraLex, Volume 4, Annex 11, ensures secure data exchange, is available as Client/Server version, and much more.

Why Metrohm Karl Fischer titrators? – A long history of success

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Karl Fischer titration is the preferred method for water content determination in pharmacopeias and countless norms, e.g. ASTM or DIN. Metrohm has been offering reliable solutions for Karl Fischer titration for more than 70 years. Ever since, the instruments have been continuously improved to meet the needs of the users.

Get the complete range from compact benchtop solutions to modular automated systems including accessories and software for volumetric and coulometric Karl Fischer titration from one supplier.
Rely on Swiss-made quality.
Benefit from our global presence in over 80 countries for local support by our service and application experts.

Learn more about KF titration in more than 100 application notes written by our application specialists:

Go to Application Finder

In addition to Karl Fischer titrators, Metrohm also offers a wide range of potentiometric titrators and a robust solution for process analysis.

Potentiometric titrators from Metrohm

Titration process analyzer from Metrohm

Karl Fischer titrator – FAQs

Karl Fischer (KF) titrators are used for measuring both free and bound water content. With the KF method, you can, for instance, determine the surface water on crystals as well as the water contained within the crystals.

KF titrators can be used for moisture determination (i.e., water content determination) in all sample types: liquids, solids, slurries, and gases
KF titrators are applied over a wide concentration range from ppm up to 100%
KF titrators are fast and highly selective
KF titrators supply reproducible and correct results

A Karl Fischer (KF) titrator determines water content in samples using a specific chemical reaction. The process is based on two redox reactions involving classical alcohol-based Karl Fischer reagents. Methanol and sulfur dioxide form an alkyl sulfurous acid, which, in the presence of water and iodine, is oxidized in a water-consuming reaction. The reaction stops when all the water is consumed, and a small excess of iodine signals the endpoint of the titration.

Manual or fully automated Karl Fischer instruments are available. Metrohm offers various solutions:

The OMNIS KF titrator can be extended by an OMNIS Sample Robot to perform up to four fully automated titrations at the same time with automated sample changing for non-stop titration: Go to automation options for OMNIS KF titrators 
The KF Titrando and the KF Ti-Touch offer the option to add automated thermal sample preparation for samples that cannot be titrated directly: Go to automation options for KF Titrando or KF Ti-Touch

When selecting a KF titrator, consider:

Water content range: Use coulometry for trace levels (ppm) and volumetry for higher concentrations.

Sample type: Liquids, solids, or gases may require different accessories (e.g., oven method for solids).

Throughput: For high sample volumes, automation (e.g., OMNIS Sample Robot) boosts efficiency.

Compliance needs: Ensure the system supports GMP/GLP, 21 CFR Part 11, and pharmacopeia standards.

Modularity: Metrohm’s OMNIS platform grows with your lab – start small and expand as needed.

Our Karl Fischer experts are happy to assist you with your questions:

Contact us

The table below compares volumetric KF titration (volumetry) to coulometric KF titration (coulometry).

	Volumetric KF titration	Coulometric KF titration
Moisture	0.1% to 100%	0.001% to 1%
Sample addition	solid or pasty samples can be added directly into the titration vessel (opening a volumetric titration cell for a short period of time does not falsify the results) liquid samples are added with syringe through a septum	liquids or gases are added with syringe through a septum: to avoid ambient humidity to enter the titration cell, never open a coulometric cell
Titer determination	regularly	not necessary
lodine addition/generation	iodine-containing titrant is added via buret	produced by a generator electrode by anodic oxidation

Learn more in our blog article:

Blog: Karl Fischer titration – When to use volumetry or coulometry

OMNIS Solvent Module, Karl Fischer Titration

To carry out volumetric titrations, you need a KF titrator with a completely equipped titration vessel, indicator electrode, dosing unit, and suitable reagents for volumetric KF titration.

OMNIS, OMNIS KF, OMNIS Sample Robot Oven, OMNIS Oven Module, Oven method, OSRO, 1030, coulometric titration cell on Oven Module, coulometry, coulometric titration, 60341100, 600349100, vial in vial holder

For coulometric titrations, you need a coulometer, with a completely equipped titration cell, indicator electrode, a generator electrode with or without diaphragm, and a reagent suitable for coulometric KF titrations.

Low levels of water in the range of 0.001% up to 1% are analyzed best with a Coulometer.

Depending on the water content, you need to select the appropriate generator electrode. The generator electrode without diaphragm combines easy handling with reliable results. For the determination of trace level water contents, we recommend using the generator electrode with diaphragm.

Metrohm offers various Coulometers, from basic stand-alone versions to high-end computer-controlled coulometric systems with automation and sample preparation options:

Go to coulometric Karl Fischer titrators

Trace levels of water in solvents and oils are analyzed best with a Coulometer.

Depending on the water content and which KF reagent you use, you have to select the appropriate generator electrode. With the generator electrode without diaphragm, only one reagent is required. The generator electrode with diaphragm is recommended for the determination of very low water contents and when using KF reagents containing solubilizers (e.g., chloroform).

Metrohm offers various Coulometers:

Go to coulometric Karl Fischer titrators

Low levels of water are analyzed best with a Coulometer. The coulometric method is very sensitive. Therefore, we do not recommend opening the titration cell to add a solid sample. Atmospheric moisture would falsify the results.

The oven method is the optimal solution for solids with low water content. Learn more about the oven method in our blog and application bulletin:

Blog: Oven method for sample preparation in Karl Fischer titration

Application Bulletin: Automatic Karl Fischer water content determination with the 874 Oven Sample Processor

Watch the following video to see the OMNIS Coulometer and OMNIS Sample Robot Oven in action.

OMNIS, OMNIS KF, OMNIS Coulometer, OMNIS Titration Module, OMNIS Solvent Module, OMNIS Dosing Module, coulometry, volumetry, coulometric titration, volumetric titration, 60338100, 60341100, 600349100, 600201300, 61115000

Yes, it is possible to perform volumetric and coulometric Karl Fischer Titration with one instrument.

The 852 Titrando offers the option to perform volumetric and coulometric KF titrations.

Explore the additional benefits of the KF Titrando product family:

See KF Titrando

The OMNIS Titrator or the OMNIS Coulometer can be upgraded with an OMNIS Coulometer Module or an OMNIS Dosing Module to allow volumetric and coulometric titrations with the same titration system.

Learn more about the modularity of the OMNIS platform:

See OMNIS platform

Yes, potentiometric and Karl Fischer (volumetric and coulometric) titrations can both be run on an OMNIS titrator. OMNIS titrators offer unparalleled modularity and allow adding functionality at any time. Additional titration modes can be combined and added whenever needed.

This modularity is unique to Metrohm's OMNIS platform, allowing laboratories to adjust quickly. Learn more about the modularity of OMNIS:

See OMNIS titrators

Do you want to learn more about KF titration?

The free monograph "Water determination by Karl Fischer titration" covers the theoretical aspects such as, reagents, chemical reactions, volumetry and coulometry, detection methods, and side reactions. It then presents water determination in different matrices, such as cosmetics, petrochemical products, plastics, and more.