Relationship between solvated polymer peak and solvent peak using mixed solvent as eluents in size-exclusion chromatography

In Size-exclusion Chromatography( SEC) two peaks are often observed for polymer samples when solvent mixtures are employed as eluents. These two peaks are solvated polymer peak and free solvent peak respectively. Theoretical analysis shows that the peak area of the solvated polymer A(3)(eff) is actually the sum of the "naked polymer" peak area A(3) and the bound solvent peak area A(1)*. A(1)(*) is equal to that of the free solvent peak A(2)* in magnitude but opposite in sign. In this study the data of A(3)(eff) A(3) and A(2)* were measured for the system of polystyrene (3)-chloroform (1)-methanol (2). The results support the analytical prediction and indicate that the preferential adsorption coefficient can be determined from either the polymer peak or the free solvent peak.