6 |
Concentration
1. Fill the feed reservoir with sample solu-
tion. When initial volumes larger than
500 ml are required, place 500 ml in
the sample|diafiltration reservoir, the
remaining volume in another suit-
able container and connect the vessels
as detailed in the diafiltration section.
Alternatively, use a larger container for
the entire sample volume and immerse
the feed and return lines directly into
the liquid.
2. Pump liquid through the system. The
recirculation rate should be in the range
200–400 ml/min, and suitable flow
should exit the filtrate line. If used, the
pressure indicator, (prod. no. VFA020),
should read approximately 2.5 bar.
3. Concentrate the sample to the desired
volume.
!
Warning: Do not run the same section of
tubing through the pump head for longer
than six hours, over use of tubing will
result in significant pressure drop and
ultimately, failure.
4. When the desired volume has been
reached, reduce the recirculation rate
to 20–40 ml/min and recirculate the
concentrated sample for 1–2 minutes to
maximise recovery.
Recovery
1. Disconnect the feed line from the lid
of the 500 ml reservoir or when using
a different container, remove the feed
line from the sample.
2. Pump residual system volume back into
the reservoir|container. (When parallel
modules are used with viscous solutions,
ensure that all modules are empty by
pinching the tubing between each of
the stacks of modules in turn).
3. For a more complete sample recovery
rinse approximately 5–10 ml per module
of water or sample buffer through the
system, and recover as before.
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