How do I ensure my Karl Fischer cell is dry?
One of the top contributors to wet titration cells is old silica beads and o-rings.
When using a volumetric Karl Fischer Titrator (such as the HI933), it is paramount that you start and end your titration with a dry titration cell. Fresh solvent, new o-rings, new or regenerated silica beads, and Karl Fischer grade solvents are all ways to keep the cell dry (you are creating a closed system). To help dry out the cell:
- Use a vacuum pump to empty the titration cell.
- Refill the titration cell with fresh Karl Fischer grade solvent to the minimum fill line.
- Carefully, without jostling the connections, lift the titration cell and give it a gentle swirl.
- This gentle swirling will catch extraneous moisture from the sides of the titration cell.
- Place the cell back on the titrator.
- If the solvent in the titration cell isn't yellow, manually add around 1 mL of fresh titrant into the titration cell (use the burette menu to do this).
- Start pre-titration - the cell should take less than 30 minutes to come to complete dryness.