protein concentration

[lesley brown]

Can anyone recommend a good way to concentrate protein solutions?

I have been using Centricon concentrators, but the losses even after using
a "passivation" procedure provided by the manufacturer are unacceptable.  I
think that the main losses are due to protein sticking to the plastic
rather than the membrane.

Improvements/suggestion of new methodology are welcome.

Respond to my email address and I'll post a summary.

Thanks.