6 Operation
K-375 / K-376 / K-377
Operation Manual, Version E
101
Distillation Parameters
With the distillation parameters all necessary steps for the distillation can be adapted:
Step 1:
Dilution with H
2
O
Step 2:
Alkalization with NaOH solution
Step 3:
Steam distillation
Parameters for Step 1 and 2
(dilution and alkalization)
Click on “H
2
O volume“ to specify the volume of
water that shall be used for the dilution of the
sample.
Click on “NaOH volume“ to specify the volume of
the sodium hydroxide solution that shall be used for
the alkalization of the sample. (The concentration of
the sodium hydroxide solution doesn‘t need to be
specified within the instrument. For BUCHI applica-
tions a solution of 32 % NaOH is recommended.)
A reaction time for the alkalization can be specified
via the “Reaction time“ button. (Also to allow the
solution to cool down again after the exothermic
neutralization.)
Parameters for Step 3 (Steam distillation)
For the mode of the steam distillation either
Auto-
matic (IntelliDist)
or
Fixed time
can be selected.
Automatic (potentiometry only):
The countdown
of the specified distillation time is not started until
the first amount of nitrogen reaches the receiver
vessel (indicated by an increase of the pH value).
The variable heat-up time is excluded from the
distillation time. Each measurement leads to a reli-
able result – regardless if performed with a cooled
down or a preheated instrument.
This mode is recommended for all samples
containing more than 1 mg of nitrogen.
The automatic mode cannot be used with colori-
metric titrations.
Fixed time (potentiometry and colorimetry):
The countdown of the specified distillation time
starts at the same time the distillation is started.
Measurements with a cooled down device will need
a longer heat-up time, which will be part of the
specified distillation time.
This mode (together with previous preheating and
priming steps) is recommended for all samples
containing less than 1 mg of nitrogen.
