Hello, I am currently working on a project related to study of the intact protein by Top Down Proteomics. Proteins are fractionated by Gelfree 8100 Fractionation Station and after fractional separation protein contain lots of SDS in solution. I have tried FASP to remove SDS but did not get much success. Acetone/Methanol ppt is also not a suitable proticol since protein quantity is very small (few ug). Is there any other way to remove SDS which can reduce the loss of protein?