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Dialysis
is an efficient technic for desalting a sample or exchanging buffer of
samples. Goals are :
-
Removing
reaction by-products
-
Removing
small reagents excess
-
Changing
a buffering agent for a more suitable one
-
Removing,
or adding, conservative agents
|
Designation |
Features
/ Applications |
|
FastDialyser |
Small
volume samples (20 µl - 1 ml) reusable device |
|
CelluSep |
1
ml to 1 L samples dialysis |
|
T1.T2.T3 |
Classic
choice for protein applications |
|
T4 |
Very
economic |
|
H1 |
Precise
MWCO and smallest contaminent content for protein, and especially
DNA/RNA application |
|
Desalting
columns |
Quick
desalting of 100 µl - 2.5 ml |
|
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Dialysis
Principle
Small
undesired molecules pass through an hemi-permeable membrane,
whilst biomolecule of interest remains inside the dialysis cell or
tube.
The
membrane should be choosen considering :
-
Molecular
Weight Cut Off (MWCO) (related mainly to pore size)
-
Compatibility
/ low adsorbtion of biomolecules
-
Resistance
to eventual solvents, agents, temperature, sterilization...
A
MWCO just below to the Molecular Weight of the protein of interest
usually allows >90-95% recovery.
Lower
MWCO, provided it remains above the MW of undesired molecules,
increases slightly the yield, but lowers also slightly the
dialysis rate. |
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