BUCHI SpeedExtractor E-916 - Manual (Page 48)

6 Operation
48 SpeedExtractor E-916/E-914 Operation Manual, Version D
6.3.2 Extraction cell selection
NOTE
The process parameters are optimized to each type of extraction cell. Therefore, never mix
extraction cells of different sizes in the same run. Different cell sizes in the same run result in inho-
mogeneous heat transfer.
There are various extraction cell sizes available, depending on the
number of positions (see adjacent table). The size of the extraction
cell does not necessarily affect the extraction time during the HOLD
stage, but it does determine the time used to reach equilibrium
(HEAT-UP stage; see section 6.4.2), as well as the amount of solvent
used for the method. As the cell is filled with solvent during an extrac-
tion process, larger cells, or only partially filled cells require more
solvent. However, the same method might require slight modifications
if performed with different sizes of extraction cells. To optimize the
amount of solvent, follow these guidelines: Extraction cell sizes
SpeedExtractor E-916
• 10 mL
P/N 051237
• 20 mL P/N 051236
• 40 mL P/N 051235
SpeedExtractor E-914
• 40 mL
P/N 051234
• 80 mL P/N 051233
• 120 mL P/N 051232
• Select the smallest cell that holds enough sample to produce accurate results.
• Take into account the volume increase resulting from drying or dispersing agents.
• For very small samples an expansion element may be used to fill up the void volume of partially
filled extraction cells (P/N 053708).
NOTE
This expansion element fits only 10 mL extraction cells. The height of this cylindrical body is 2 cm.
Hence, one or two displacer can be used to fill up the remaining space, depending on the sample
volume.
6.3.3 Packing of the cells
A Insertion of the lower filter, metal frit and threaded plug screw
a
b
c
g
d
c
b
a
Put the extraction cell upside down (with the serial
number at the bottom) on a bench top and insert first
a filter a of disposable glass fiber (P/N 11055932) or
cellulose (P/N 049569) using tweezers. Place the filter
on the offset of the cell and make sure that it is in full
contact with the cell. The filter prevents blockage of the
metal frit and is therefore mandatory to use. The glass
fiber filters are suitable for all application. They are re-
quired for fatty, fine powdery samples, for aqueous ex-
tractions and samples with remaining moisture, in order
to ensure an adequate filtration. They are also recom-
mended for trace and ultra-trace analysis, as their use
results in lower blank values. For other samples and
solvents, the paper filter might be sufficient too.
Place the metal frit b (P/N 049568) onto the filter and
close the bottom of the cell with the plug screw c (P/N
053209) using the plug screw tool d (P/N 053607).
Make sure that the concave surface of the plug screw
points to the cell.