Topological separation of linear and star-shaped polystyrenes by off-line 2D chromatography. Stars having high molar mass arms and quantification of the star fraction

Off-line 2D separations on mixtures of linear and star-shaped polymers were performed using temperature gradient interaction chromatography (TGIC) as a first and SEC as a second dimension. The experiments resulted in clear separations of the linear and star shaped-structures for arm molar masses up to 42,000 g/mol. The resolution is nearly independent of the molar masses of the arms and depends only on the number of star arms. From the 2D chromatograms it is possible to determine the molar mass of the first branched structure, i.e. the three arm star. The evaluation of the relative peak volume allows a reliable estimation of the amount of branched structures in the complex mixture.