Probably use a flame ionization detector. The key here is to figure out the volume per unit length of the mobile phase and the stationary phase. The separation method of choice for biological macromolecules is electrophoresis. One can get higher resolution with electrophoresis, which is necessary with proteins since a 1 amino acid change may be enough to so change the functioning of the molecule that it's essential to know every little detail. With structural polymers, one always has a molecular weight distribution, so one really has no need for counting exactly the contribution of individual numbers of monomers.
Sample size can be much larger as well.
If you elute a carboxylic acid through a reverse-phase LC column at pH 2, you get a sharp peak. If you elute it through the same column at pH 9, you get a sharp peak with a longer retention time. If eluted at pH 6, a broad band results. Thus, one is eluting a pure species. But at pH 6, one has a mixture of the acid and its conjugate base, and the two forms rapidly interconvert.