Metrohm 900 - Page 506

31.9 Coulometric Karl Fischer titration
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490
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900 Touch Control
Problem Cause Remedy
The Control parameters
are set incorrectly.
￭ Reset the Control parameters to default
values.
The titration time is
too long.
The drift during condition-
ing is not stable.
￭ Wait before starting the titration until the
drift has become stable.
The parameter Start drift
is set too high.
￭ Set the Start drift lower.
￭ Adjust the Stop drift or use the Relative
stop drift.
The parameter Stop drift
is set too low.
￭ Set the Stop drift higher or use the Rela-
tive stop drift.
The water quantity is too
high.
￭ Observe the sample size and water con-
tents in accordance with .
The Control parameters
are set incorrectly.
￭ Set the parameter Dynamics lower and
the parameter Max. rate higher.
The result is too
high.
The titration cell is not yet
correctly conditioned.
￭ Shake the titration cell and wait until the
drift is stable.
The sample contains oxi-
dizable substances.
￭ Consider using a KF oven.
￭ See technical literature.
The parameter Stop drift
is set too low.
￭ Set the Stop drift higher or use the Rela-
tive stop drift.
The drift correction is too
small (e.g. for the use of a
KF oven or for manual drift
correction).
￭ Start the titration as long as the gas flow
still exists between the conditioning vial
and the titration cell.
￭ Set the parameter Drift correction to
auto (= automatic drift correction).
The result is too
low.
The sample releases iodine. ￭ Consider using a KF oven.
￭ See technical literature.
The parameter Stop drift
is set too high.
￭ Set the Stop drift lower.
The drift correction is too
large (e.g. with excessively
high start drift, with fluctu-
ating drift or with manual
drift correction).
￭ Ensure stable and lower drift.
￭ Set the parameter Drift correction to
auto (= automatic drift correction).