BUCHI KjelSampler K-377 - Manual (Page 99)

6 Operation
99 K-375/376/377 Operation Manual, Version B
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 alka-
lization)
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: The countdown of the specified distil-
lation 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 reliable 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: The countdown of the specified distil-
lation 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.