8 replies to this topic

[xxcici]

Hi, I am trying to use dialysis tube to concentrate my virus. Then today, I used buffer without virus inside the dialysis tube  and 10% polyethylene glycol (MW is 35000) solution outside the dialysis tube for the experiment.  The cutoff molecular weight of the dialysis tube is 3500. After two hours, I did not notice the decrease of buffer inside the tube. I searched the poster in this website and find one posted in 2006 saying by someone that this method is very fast which may take less than 1 hour. So, I want to ask if somebody know what happened to my experiment. Thank a lot!

[bob1]

What concentration buffer did you use inside and outside?

[xxcici]

glycine buffer with pH of 9.5 and 0.3 M NaCl.

[bob1]

Would you notice an less than 10% change in volume?

[xxcici]

Yes, it needs time to make the volume reduced. But why somebody ever said that the volume could be reduced super fast. Here is the link: http://www.protocol-...sts/20733.html.

[phage434]

Was it a typo that your MW of PEG was 35,000?  I have 3500 and 8000 on my shelf, but not 35,000.  If it was really 3500, then your dialysis membrane will be letting it through.

[xxcici]

Yes, I am using PEG with MW of 35 000, not 3500 and 8000.

[jakester]

Why not try spin ultrafiltration, i.e. with an Amicon or Spin-X 100KD MWCO filter?  Bam, you're done.

[xxcici]

Hi Jakester, thank you very much for your suggestions. Could you provide me with more information about the spin ultrafiltration? I do not know where I can get that stuff and how it looks like, as well as how to use it. Thanks again.