LimsPulse
Titration & electrochemistry

Karl Fischer Titrator (Volumetric)

Measures the water content of a sample by titrating it with an iodine-containing Karl Fischer reagent from a motorised burette. The standard method for water in APIs, excipients and many finished products.

  • Pharmaceutical
  • Chemicals
  • Food & beverage
  • Petrochemicals
  • Cosmetics
Photo of a Karl Fischer Titrator (Volumetric)
Photo: Datamax, Public domain (cropped), via Wikimedia Commons
Follow your site SOP
This is a typical operating sequence for learning. Your instrument model and approved SOP take precedence.
STAGE 1

Before you start

  1. 1Check the titrator is within its calibration due date and the titre of the reagent is current.
  2. 2Check the molecular sieve in the drying tubes is active (replace or regenerate it as per SOP).
  3. 3Fill the cell with fresh solvent to cover the electrode pins.
  4. 4Make sure all joints and the septum are tight.
  • KF reagents contain methanol and imidazole or pyridine-type bases: handle them in a fume hood with gloves and eye protection.
STAGE 2

Conditioning and drift

  1. 1Start conditioning. The titrator adds reagent until the cell solvent is dry.
  2. 2Wait until the drift is low and stable (commonly below 20 µg/min, or the limit in your SOP).
  3. 3Record the drift before the first determination.
  • A high or unstable drift means moisture is entering the cell. Fix the leak before running samples.
STAGE 3

Titre determination

  1. 1Determine the titre with a water standard (for example sodium tartrate dihydrate) at the frequency in your SOP, usually daily or before each series.
  2. 2Use the mean of at least three determinations that meet the precision limit.
STAGE 4

Sample analysis

  1. 1Weigh the sample by difference, choosing a mass that uses a reasonable part of the burette volume (often aimed at about 10–90% of the burette).
  2. 2Add the sample quickly through the port to limit exposure to air, and enter the exact mass into the software.
  3. 3Start the titration and let it run to the endpoint.
  4. 4Run duplicate determinations and check they agree as required by the method.
  • Do not leave the cell open longer than needed.
  • Replace the solvent when the cell is about two-thirds full or when titrations slow down, as the solvent capacity is exhausted.
STAGE 5

Shutdown

  1. 1Drain or exchange the spent solvent into the labelled KF waste container.
  2. 2Leave the cell closed and conditioned (standby) or clean it as per SOP if it will not be used for a long time.
  3. 3Complete the instrument usage log.
In LimsPulse · Calibration Management

Keep every KF titrator (volumetric) in control: usage logs, calibration and maintenance schedules, and automatic blocking of overdue instruments.

See how