water withdrawal with PEG20.000 - Does it drag glycerol along too?-PLEASE HELP! (Nov/13/2009 )

Hi all

I used PEG20.000 to reduce my protein sample volume from 100μl to 50μl. I put flakes of PEG20.000 on a microdialysis tube. Before the water withdrawal my protein sample contained 20% glycerol. So my question is: did PEG20.000 drag glycerol along with the water?. Does my 50μl protein sample contain 20% or 40% glycerol??.

Please help a biologist who does not know much about chemistry. I would be very gratefull for an answer!

anything that can pass through the pores of the dialysis membrane will. the concentrations your buffer components should remain constant. you will find that some peg also passes through the membrane, in the other direction.