Metrohm 870 KF Titrino plus Manual - Manual (Page 18)

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870 KF Titrino plus
3 Water determination according to Karl Fischer
(KFT)
Karl Fischer Titration is a method for volumetric water determination. Con-
ditioning is carried out automatically both before and after the actual titra-
tion. The reagent dosing is controlled in such a way that a predefined
endpoint is reached as quickly and as accurately as possible. The volume
steps and the rate of reagent dosing are regulated by the difference
between the current measured value and the predefined endpoint. This
means that titration is performed more slowly in the control range and
that smaller volumes are added. The titration is stopped at the endpoint
either drift-controlled or after a waiting time. The volume dosed until the
endpoint is used to calculate the water content of the sample.
EP
KFT Ipol
KFT Upol
EP
V/mL
Continuous
dosing
Initial
dosing
V/mL
V/mL
U/mV
t/s
I/µA
Control range
Control range
Figure 3 Reagent dosing for KFT