24
Start up of cassettes
5.9 Cassette Storage
Sartorius Stedim Biotech filter cassettes can be stored after use. To avoid micro-
bial contamination preservatives have to be used.
All membranes will lose their filtration performance if allowed to dry out or
freeze. Always store filter cassettes in moist condition.
5.9.1 Short Term Storage
We recommend the following preservatives for cassettes assembled in a holder short
term storage (up to 8 weeks):
Preservative
Concentration
Formaldehyde
2–3% by weight
Ethanol
Do not use denatured alcohol
20% by weight*
NaOH
0.1 N
* Hydrosart
®
can be stored in Etanol 20–40% by weight
For short term storage proceed as follows:
t
Clean the filter cassettes [
Æ
Chapter “Cassette Disinfection”, page 23].
t
Recirculate the preservative for 5 minutes through the system at the same flow
rate used to flush the filter cassettes. The preservative must flow through both
permeate outlets.
t
Close feed inlet, retentate outlet and both permeate outlets.
t
Do not allow the cassettes to dry out or freeze.
5.9.2 Long Term Storage
We recommend the following preservatives for cassette storage outside of the holder:
Preservative
Concentration
Formaldehyde
2–3% by weight
Ethanol
Do not use denatured alcohol
20% by weight*
NaOH
0.1 N PESU and Hydrosart
®
up to 12 months
* Hydrosart
®
can be stored in 20–40% by weight Ethanol
For long term storage proceed as follows:
t
Clean the filter cassettes [
Æ
Chapter “Cassette Disinfection”, page 23].
t
Recirculate the preservative for 5 minutes through the system at the same flow
rate used to flush the filter cassettes. The preservative must flow through both
permeate outlets.
t
Remove the filter cassette from the holding device.