Diafiltration|Desalting
1. Set up the system as illustrated in
Diagram 8.
2. Rinse the system as detailed previously.
3. Place the solution to be purified in a
suitable diafiltration reservoir. For vol-
umes up to 500 ml the Vivaflow 500 ml
sample|diafiltration reservoir (VFA006),
is recommended. Ensure the lid is firmly
closed.
4. Fill the large feed reservoir with exchange
solvent and pump sample through the
system as for concentration.
5. As liquid passes through the membrane,
the vacuum created in the diafiltra-
tion reservoir draws in exchange solvent
through the feed line from the large res-
ervoir. Over 99% solvent exchange
can be accomplished with an exchange
volume of approximately 5 times the
sample volume.
Concentration
1. Fill the feed reservoir with sample
solution.
2. Pump liquid through the system.
The recircu lation rate should be 200–
400 ml/min, (500–900 ml/min for two
modules), and suitable flow should exit
the filtrate line. If used, the pressure indi-
cator should read approximately
2.5 bar.
!
Warning: Do not run the same section
of tubing through the pump-head for
longer than 6 hours, overuse of tubing
will result in significant pressure drop and
ultimately, failure.
3. Concentrate the sample.
4. When nearing the desired volume, reduce
the recirculation rate to 20–40 ml/min
and recirculate the concentrated sam-
ple for 1–2 minutes to increase sample
recovery.
Recovery
1. Remove the feed line from the sample.
2. Pump residual system volume back into
the reservoir|container.
3. For a more complete recovery, rinse
25–50 ml of water or sample buffer
through the system, and recover as
before.
14 |
Diagramm 8: Buffer exchange | Desalting with
Vivaflow 50R and Vivafow 200
To Next Page
Loading...
