Coulometric Karl Fischer Titrations

Coulometric Karl Fischer Titrations (C-KFT), a notable technique for moisture testing, provides accurate and reliable determination of water content in diverse substances.

Principle

C-KFT employs a coulometric cell where iodine is electrochemically generated within the analyte. This generated iodine reacts with water present to form hydrogen ions, regenerating the original reagents through a redox reaction.

Equipment

Essential equipment for C-KFT includes:

  • Coulometric cell
  • Electrodes (anode and cathode)
  • Titrant solution (methanol with iodine)
  • Sample vessel
  • Karl Fischer reagent

Procedure

A known mass of sample is added to the sample vessel. A Karl Fischer reagent, a strong drying agent, is added to remove water from the sample. The electrochemically generated iodine reacts with any remaining water, reducing the amount of water present.

Endpoint Detection

The endpoint is reached when the water content in the analyte has been depleted. This is detected by a voltage change in the coulometric cell. The amount of iodine generated is proportional to the water content in the sample.

Advantages

C-KFT offers several advantages, including:

  • Accurately determines water content in various substances
  • Highly sensitive, detecting low moisture levels
  • Rapid and efficient analysis time

Applications

C-KFT finds applications in moisture testing across industries, including:

  • Pharmaceutical
  • Food and beverage
  • Chemical and petrochemical