BUCHI Extraction Unit E-816 HE - Manual (Page 42)

6 Operation
42 E-812/816 Hot Extraction Operation Manual, Version B
6 .4 .3 After the extraction process
The end of an extraction process is indicated on the display and audible by a beep sound (if selected
in the instrument settings).
After an extraction process is finished, proceed as follows:
• Confirm the message on the screen by pressing the backward button.
• Empty the solvent tank.
• Move up the rack.
• Carefully remove the glass tubes or thimbles from the beakers by means of the pliers.
• Place the glass sample tubes or thimbles on a tissue and let them dry under the fume hood.
• Dry the beakers in a drying oven at 100 °C or in a vacuum oven at 200 mbar and 70 °C until they
have a constant weight.
• Let the beakers cool down to ambient temperature in a desiccator.
• Weigh the beakers and calculate the resulting fat content.
6 .4 .4 Emptying the solvent tank
• To empty the solvent tank put the solvent outlet hose into the waste container.
• Press Solv. and confirm the appearing message by pressing Yes.
NOTE
Make sure to empty the solvent tank after each extraction.
6 .4 .5 Reusing the solvent
• The solvent can be reused directly or after being distilled in a rotary evaporator.
When the instrument was used for the first time:
• Waste the solvent
When a different solvent was used before
• Waste the solvent
After incorrect procedure:
• Clean the glass assembly
• Clean the solvent tank
• Waste the solvent
NOTE
When working with petroleum ether from 40 - 60 °C: Renew the whole solvent after 10 extractions
to achieve a reproducible extraction behaviour. The mixture changes within time because the light
fraction evaporates and the heavy fraction accumulates.