So I have been asked to separate a polymer (polyurethane) into high molecular weight and low molecular weight components. I have access to Sephadex LH-20, a simple glass column, acetone (a List II chemical), ethyl acetate, and hexane. I may be able to get access to other solvents, as long as it is not anything exotic. I also have a couple TLC plates. I have experience with simple column chromatography (with silica gel) and GC-MS, although the labs I'm curerntly using are probably at high-school to simple undergraduate level with no fancy equipment or anything. In theory all I need to do is to pack the column with sephadex, run the appropriate solvent through it and add my polymer sample (dissolved in the same solvent) on top. Simple enough, except for two problems: One, I cannot find any appropriate protocols for what I am supposed to be doing. Most of the protocols I found are for separating proteins, and they all require a buffer of some sort. Do I need a buffer, even though I'm separating polyurethane? Or do I just soak the sephadex in my solvent until it swells, pack the slurry in the column to make a gel bed and just run my sample through the whole thing (while adding solvent continually until my arm cramps)? Two, as sephadex is expensive, I need help in determining an appropriate solvent to use. TLC doesn't seem to help much here as it uses a different stationary phase (silica). Anyone have any ideas on what solvent or mixture of solvents I should use as the mobile phase? Thanks in advance.