Product Recovery
Following the concentration/diafiltration process, the
product must be recovered from the system.
Product in Concentrate
After processing, a significant portion of the product is on
the membrane in the form of a “gel layer” and needs to be
recovered back into the solution before the system is drained.
Recirculating fresh buffer can recover most of this gel layer,
but may significantly dilute the product that you just
concentrated. The following procedure can improve recovery
without significant dilution. The actual procedure may have
to be varied depending on TFF system configuration.
STEP 1
Following concentration/diafiltration, open the retentate
valve and close off the filtrate line with a valve or screw
clamp. Adjust the pump to give a retentate flow rate of
40-50 mL/min. Circulate the product for 5-10 minutes.
STEP 2
Stop the pump. Put the retentate tubing into a collection
vessel. Start the pump and slowly pump out the product
into the collection vessel. Stop the pump just before the
volume in the reservoir reaches the bottom. Add to the
reservoir a volume of buffer equal to the system hold-up
volume. Pump out the product into the collection vessel
stopping just as the liquid level reaches the bottom of
reservoir. (This method displaces most remaining product
left in the cassettes and hardware.) Record the volume
collected.
STEP 3
Add just enough volume of buffer to the feed reservoir to
allow circulation without pulling in air. Circulate for 10
minutes to try and recover additional product. The
remaining liquid in the system can be pumped out into a
separate container by allowing air to be pumped through
capsule to displace it. A decision can then be made
whether to combine this volume with the main product.
Product in Filtrate
If the product is in the filtrate, raise the vent port so it is
higher than the collection vessel. Make sure the end of the
filtrate tubing is placed in the vessel. Open the vent port
and allow any remaining filtrate in the capsule and tubing
to be drained.
Cleaning
If the Minimate
™
TFF Capsule is to be reused, it must be
cleaned after use and properly stored. Recommended
cleaning solutions and protocols are given in Appendix A.
Storage of Minimate TFF Capsules
The objective for proper storage is to ensure the membranes
remain wet and to prevent microbial growth during the time
the membrane cassettes are not being used.
Recommended storage agents for Minimate TFF Capsules.
Storage Agents:
PERIOD SOLUTION
<3 days
Sterile water or saline solution
<6 months
0.05N - 0.1N NaOH
>6 months
15% gl 0.05% sodium azide
Recommended storage temperatures: 4°C - 15°C (optimal),
25°C (maximum). Do not freeze
Disposal of Minimate TFF Capsule
It is recommended that after use, and prior to disposal, the
Minimate TFF Capsule be flushed with clean water, sealed
into an autoclave bag, and autoclaved at either 121ºC for 30
minutes, or at 135ºC for 15 minutes to sterilize. Dispose of
the Minimate™ TFF Capsule in the bag, and do not open
after autoclaving.
DO NOT seal the inlet and outlet connectors of the
Minimate TFF Capsule prior to autoclaving as this
will cause a build up of pressure, which may rupture
the device.
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