| Close |
Message | User | Date(yyyy-mm-dd) |
|
|---|
 |
negative charge on CE membranes? | haitzer | 2001-04-27 | Click here to register. |
|---|
I found the diffusion of EDTA (at pH 7) through CE 1000 membranes to be very slow. As the MW of EDTA is 292, I did not expect this.
Then I ran experiments with small organic acids carrying different amounts of negativ charge. The results showed that the diffusion of acetic acid and glycolic acid (1 neg. charge) across CE 1000 membranes was fast, whereas oxalic acid (2-) diffused slower and citric acid (3-) diffusion was very slow.
Is this a phenomenon that is well known? Is there anything that could be done to effectively dialyse small molecules carrying 2 or more negative charges with CE membranes? | | |
| dave | 2001-05-01 | Click here to register. |
|---|
 | CE membranes are made of a mix of cellulose and cellulose acetates and generally have a slight negative charge.
To speed the dialysis of polyanions you could, use a larger MWCO membrane, lower the pH to the isoelectric point of the membrane (no, I don't know what that is), or us a membrane made from something other than cellulose. |
|
|
| Thanks for visiting.- To ask question or answer a question, you need to register here.
- You can browse by clicking on a message subject to see the complete message.
- If you have previously registered, you can log in below.
|
|
Back to Top
Newer