Metrohm 754 Dialysis Unit - Manual (Page 35)

4 Malfunctions – Maintenance
754 Dialysis Unit
32
4.2.6 Replacing the dialysis membrane
The dialysis membrane may have to be replaced in the following cases
(see section 4.1 as well):
• Reduced yield from dialysis
• Membrane has dried out, or is damaged by depos-
its or bacterial growth
• Irremediable blockage of the sample channel (sample
can no longer be conveyed through the dialysis cell)
To replace the membrane, proceed as follows (see Fig. 7):
1 Dismantle the dialysis cell
• Unscrew the four inlet/outlet leads from the dialysis cell 34 34
and remove cell from cell holder 66.
• Loosen the 5 screws 39 39 completely using the 6.2621.070
Allen key and separate the top part 38 38 from the bottom part
35 35.
• Remove old dialysis membrane 37 37.
Use only ultrapure water or ethanol to clean the dialysis cell;
organic solvents (e.g. acetone) will cause damage to the plexiglas
cell !
2 Clean dialysis cell
• Rinse the sealing ring 36 36, the bottom part 35 35 and the top part
38 38 of the dialysis cell thoroughly with ultrapure water and dry
with N
2
or a lint-free cloth.
3 Prepare dialysis membrane
• Take a new dialysis membrane 38 38 (e.g. 6.2714.010) out of its
packaging using the 6.2831.010 pincette and immerse in a
Petri dish containing ultrapure water for approx. 2 min until
the membrane is completely saturated with water.
4 Insert dialysis membrane
• Place bottom part 35 35 on a paper wipe with the inside facing
upwards.
• Insert sealing ring 36 36 in the appropriate recess in the bottom
part 35 35.
• Using the 6.2831.010 pincette, insert the wet dialysis mem-
brane 38 38 (e.g. 6.2714.010) inside the sealing ring 36 36 on the
bottom part 35 35.