Manual

2.4 Practical tips
768 KF Oven
13
2.4 Practical tips
Sample introduction via top opening of the insert tube
This possibility can be used if several samples can be
heated in succession in the same sample boat.
Add samples to sample boat with a syringe or open screw
cover.
Selection of the carrier gas
N
2
should always be used as the carrier gas when the hot
sample is sensitive to air or oxygen and evolves substances
which interfere with the KF reaction.
Temperature setting
Select temperature as high as the sample allows (high tem-
perature = shorter analysis time): The sample must evolve no
oxidizable substances except water.
Extraction time
An extraction time of ca. 2 min should be set on the attached
titrator to prevent the titration being aborted before the sample
evolves water.
Conditioning system
To condition the entire system (without sample boat and without
sample) before the start, the valve can be set to "TRANSFER"
at the KF Oven.
References
- Hydranal ® Practical Course, Riedel-deHaën, 1987
- G. Wieland, Karl Fischer Titration, GIT Verlag, Darmstadt,
1985
- Following Metrohm Application Bulletins (available free of
charge):
No. 109 KF water determination with the KF Drying Oven
No. 145 Determination of low water contents in plastics
No. 217 KF water determinations in pharmaceutical prepara-
tions by the KF oven method.