Analytical and Bioanalytical Chemistry

, Volume 411, Issue 20, pp 5063–5078 | Cite as

Comprehensive branching analysis of star-shaped polystyrenes using a liquid chromatography–based approach

  • Douglas Murima
  • Harald PaschEmail author
Research Paper


The comprehensive branching analysis of complex polymers is still a challenge in advanced polymer analysis. Average branching information (average number and length of branches) can be obtained by spectroscopic methods, mainly NMR spectroscopy. The determination of the branching distribution, i.e., the concentration of macromolecules with a given number of branches, however, requires fractionation. Typically, size exclusion chromatography is used that separates the complex mixture with regard to molecular size in solution and not strictly with regard to the number of branches. In the present approach, model star-shaped polystyrenes were synthesized with a pre-determined architecture to give theoretical three-arm, four-arm, and six-arm structures. The branched samples were compared with a linear analogue of comparable molar mass known not to contain branching. Triple detector size exclusion chromatography with refractive index, multiangle light scattering, and online viscometer detection was used to determine absolute molar masses, radii of gyration, and branching distributions of the star-shaped polymers. 1H-NMR was used to calculate the average functionality and a reasonable agreement between the results of the two methods was obtained. Thermal gradient interaction chromatography and solvent gradient interaction chromatography were employed to separate the complex reaction products according to chemical composition (number of branches) and to resolve by-products. The separation capabilities of the two chromatographic techniques were compared and evaluated. Comprehensive two-dimensional liquid chromatography was used to separate the polydisperse star-shaped polystyrenes with regard to both branching and molar mass.

Graphical abstract


Star-shaped polymers Polystyrene Size exclusion chromatography Multiple detectors Solvent gradient interaction chromatography Thermal gradient interaction chromatography 


Compliance with ethical standards

There was no research involving human participants and/or animals. The work has been submitted with the consent of all authors.

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

216_2019_1846_MOESM1_ESM.pdf (310 kb)
ESM 1 (PDF 309 kb)


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Chemistry and Polymer ScienceUniversity of StellenboschMatielandSouth Africa

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