Karl Fischer Titration (KFT)
Definition
Coulometric or volumetric titration using Karl Fischer reagent (iodine / sulphur dioxide / base / methanol) that reacts stoichiometrically with water. Used to measure trace water content in transformer oil (typically below 30 ppm); also used to measure moisture in pharmaceutical solids and food products.
- Reagent components
- Iodine, sulphur dioxide, base, methanol
- Titration types
- Coulometric and volumetric
- Typical target
- Transformer oil moisture, below about 30 ppm
- Also used for
- Pharmaceutical and food moisture testing
Common questions
What is the difference between coulometric and volumetric Karl Fischer titration?+
Coulometric titration generates the titrant electrochemically in situ and suits very low water content, while volumetric titration delivers a standardised titrant from a burette and suits samples with higher water content.
Why does water content matter specifically in transformer oil?+
Dissolved water accelerates breakdown of the oil's insulating properties and can point to a fault or contamination, which is relevant when investigating failures in electrical equipment.
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