Development of Karl Fischer Reagents

I-1. Questions & Answers about Karl Fischer Reagents
(1) Anode chamber
(2) Cathode chamber
(3) Anode
(4) Cathode
(5) Diaphragm
(6) Rotor
(7) Drying tube for anode chamber
(8) Drying tube for cathode chamber
(9) Stopper
(10) Sample injection port
(11) Drain cock
(12) Detection electrode
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Helpful hint - 2
(7)
(2)
(4)
(3)
(5) (6)
Figure 3: Electrolysis Cell
(9)
(10)
(1)
(12)
Are there any criteria to guide the choice between volumetric and
coulometric titration?
The following factors should be taken into account when making this
decision.
(1) Using the characteristics of coulometric titration
The need to check titer is eliminated, since it is not necessary to
standardize the Karl Fischer reagent. This feature is very useful for
reducing the work involved in everyday analysis tasks.
(2) Moisture content as a criterion
Coulometric titration should be used if the moisture content is 1% or
lower. It is especially useful for measuring moisture content at the ppm
level within tolerances of a few ppm.
Coulometric titration can still be used if the moisture content is higher
than about 1%, but it is necessary to use small samples, and analysis
results will be influenced by weighing error. Normally volumetric titration
is used in such cases.
(3) Electrode reactions
Coulometric titration is not used for substances that react with
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(11)