I am trying to concentrate a protein using Amicon Ultra centrifugal device. I have done this several times before without any problems.
This time when I added 4ml distilled water to wet the filter before use then centrifuged the Amicon Ultra centrifugal device for 5 min at 200xg -4C , however nothing going through the filter!?
I used another Amicon Ultra centrifugal device from the same let number and I used Amicon Ultra centrifugal device from different lot number but still having the same problem!?
Does anyone have any suggestions to help my Amicon Ultra centrifugal device to work?