Karl Fischer titration apparatusIt is an instrument used by our pharmaceutical company to control moisture. The instrument requires professional maintenance, and now we will share with you the daily maintenance of our company.

1. Environmental temperature and humidity

The manual states that the temperature should be between 5-40 ℃ and the humidity should be less than 80%. Have you achieved this? When you fail to achieve it, the equilibrium time is prolonged, and the drift value will constantly change during equilibrium. After repeated titration, the temperature can generally be reached in a laboratory. At this time, you need to dehumidify the air.

The Karl Fischer titration instrument has three solvent bottles, each containing titration solution, solvent, and waste liquid. Each of the three solvent bottles has a dryer, and there is also a dryer on the instrument. Molecular sieves are placed in all four dryers (in order to observe the degree of water absorption, some color changing silica gel can be placed in the middle, and a new molecular sieve can be replaced through the indication of the color changing silica gel). The dryer on the instrument has the greatest impact on the stability of the instrument. If not replaced in time, the instrument balance may be prolonged or even unable to balance. In addition, the sealing of the instrument should also be maintained well to reduce the impact on the environment.

2. Selection of reagents

The selection of reagents is very important, and the quality directly affects the accuracy of detection and the stability of the instrument. We choose pyridine free Karl Fischer titration solution as the titrant. However, Karl Fischer titration solution has a disadvantage, that is, if the moisture meter is not used for a few days, the titrant in the burette and pipette inside the instrument will stratify. Before use, all the stratified liquid must be discharged, otherwise it will affect the accuracy of the measurement.

3. Use of instruments

Before using the instrument every day, shake the bottle containing the titrant a few times to make it uniform, and then check whether there are bubbles or layers in the pipeline through which the titrant flows. If there are, remove them by draining. Perform pre titration and calibrate the titrant (as the titrant will evaporate and the concentration may change, the specific calibration time should be determined based on the humidity of the environment to ensure the accuracy of the measured data).

4. Daily meticulous maintenance, careful upkeep, and careful operation are necessary to ensure the accuracy of the Karl Fischer titration results.