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Keywords:

  • FT-IR;
  • graft copolymers;
  • high performance liquid chromatography (HPLC);
  • MALDI-TOF mass spectrometry;
  • microstructure;
  • separation techniques

Abstract

Thumbnail image of graphical abstract

2D separation of poly(MPEG-MM 2), 1st dimension: LC-CC, 2nd dimension: SEC.

Summary: The chromatographic analysis of hydrophilic copolymers is complicated due to the fact that in most cases aqueous eluents must be used. In aqueous eluents different polar and ionic effects may disturb the selective interactions between the macromolecules and the stationary phase making it impossible to separate such copolymers with regard to chemical composition. Therefore, 2D chromatography combining a separation according to composition with a separation according to molar mass has been applied mostly to polymers that are soluble in organic solvents. The present contribution describes experimental approaches to analyze such hydrophilic copolymers by 2D-chromatography. For a model polymer system resulting from the copolymerization of methacrylic acid and a poly(ethylene glycol) macromonomer, it is shown that different analytical techniques including SEC, LC-CC, MALDI-TOF MS and 2D chromatography can be used to analyze the different parameters of molecular heterogeneity of such copolymers.