PD10 columns work reasonably well, but sometimes tend to bind some proteins nonspecifically. In that case, try Pierce Zeba Desalting columns, which perform significantly better in our hands and are available for a large range of volumes (http://www.piercenet.com/objects/view.cfm?type=productfamily&id=c6b5ebdf-7e66-4279-bb9e-2140ec349b3e).

Alternatively, if you observe sample loss in spin columns, Slide-A-Lyzer cassettes work very well, too, they are basically preformed dialysis chambers, that provide high surface-area to volume ratio that maximizes diffusion rate compared to cylindrical dialysis tubing into which you load/recover your sample using a hypodermic needle (http://www.piercenet.com/browse.cfm?fldID=04010130).

Depends on your application if imidazol needs to be removed or not.

Pre-treating Sephadex resin with eg BSA can improve yields in the first run, but with the "short" columns, complete removal (>95%) of the contaminating salt may be difficult, due to overlapping peaks (salt vs protein).

Having that said, another option are centrifugal concentrators like ...spin or ...con etc. Concentrate, dilute, concentrate, dilute. The small molecules run through and your protein of interest is retained. The nice thing is that you may process as many samples as your centrifuge can hold and you'll achieve a salt removal of at least 95% per run (so, just multiply). A potential drawback is the possibility of partial protein adsorption to the membrane, so you'll have to block with BSA or similar again and/or test different membranes if this should be the case and a problem.

Thanks a lot guys - What do you think about this? also an option -

http://www.piercenet.com/browse.cfm?fldID=0ED30A38-6E1B-4E79-A664-F83B7FF6631C

Hi Arik,

those from Pierce did well in my hands with antibodies. They may be easily re-used after flushing for the same samples (or when the risk of some low cross-contamination is not a problem)

Wo