User guide
6 Operation
19 B-411/E-416 Operation Manual, Version E
6.5 Choosing the heat output
When the preheating procedure is finished, the hydrolysis can be started. For this purpose we recom-
mend to switch the energy regulator to position 2 for four samples and to position 3 for six samples.
Depending on the boiling behavior, less heat can be provided when setting the regulator to position 1
or more heat can be provided by setting it to position 3.
6.6 Hydrolysis
To carry out a hydrolysis proceed as follows:
Reduce the heat output (position 2 - 3)•
Insert the vessels containing the samples into the instrument•
Put the prepared glass sample tubes into the rubber couplings•
Close unused positions with the supplied stoppers Ø 45 mm on the suction tube•
Put the caps onto the digestion vessels and install the sample aspiration tube•
As soon as the sample starts boiling switch on the waterjet pump.•
The hydrolysis time depends on the sample. From the start of the boiling on it takes a minimum of •
15 and a maximum of 60 minutes (usually 30 minutes is an appropriate time).
Foaming can be suppressed by the addition of small acid injections
(HCl 4 mol/l). It is recommended to switch on the external pump
only after the samples are boiling evenly and no further foam is to be
expected. Thus a premature sample extraction is avoided.
Fig. 6.7: Hydrolysis
6.7 Filtration
After expiration of the hydrolysis time, switch off the heating and
add hot distilled water (40 - 50 °C) to each digestion vessel to a
level of approx. 1 cm under the sample aspiration tube.
To filter the hydrolysate solution over the glass sample tubes, raise
the lift device to immerse the sample aspiration tubes into the solu-
tion. As soon as the contents of the individual digestion vessels are
completely transferred, rinse them with hot distilled water
(40 - 50 °C) portion by portion. The rinse volume until neutral
reaction is approx. 250 ml per sample.
Fig. 6.8: Filtration