Ionic liquids for Karl-Fischer titration

Karl Fischer titration is known for decades since original publication by K. Fischer in 1935.[i] By now, it has been adopted by industrial and research labs as quick and reliable method of water determination, and equipment and reagents for this titration are widely commercially available. Karl Fischer titration has a wide scope of possible analytes, is precise, quite selective and easily automated. The problems however appear when there is a need to reliably analyse samples that are not soluble in the standard solvent – methanol. These samples include some foods, pharma products, polymers. Often while titration attempt is undertakes, slow release of water over long periods of time occurs and no reliable result can be obtained.

Luckily, ionic liquids can help to solve this issue. ILs have excellent solubilizing power for variety of compounds, including some polymers, biomaterials and biomolecules. This allows for the analysis of ready pharmaceutical formulations, API-s, foods.

Ionic liquids offer:

  • High solubility of multitude of species, including compounds that are badly soluble in other solvents. That can also help with release of water that was trap deep in the structure of the analyte.
  • Tuneable properties, allowing finding the right solvent for analytes of different nature. The simplest example is the possibility to choose between hydrophilic or hydrophobic IL-
  • Ultralow vapour pressure that prevents pressure build-up and release of VOC-s.
  • Non-flammability, allowing safer work conditions.
  • Stability in the wide temperature window allowing to perform analysis at different temperatures

If you have problems with water determination of your sophisticated samples, contact our team, and we will eb happy to offer you ionic liquids that are best suitable for your system


Text: Dr. Svetlana Cadu, Iolitec 2019



[i] K. Fischer Angew. Chem., 48: 394-396. doi:10.1002/ange.19350482605