By variation of the composition of iso-propanol / water mixtures as eluent for liquid chromatography on a cyano column the retention behavior of a series of poly(2-ethyl-2-oxazoline) (PEtOx) standards with w-acetyl end groups could be shifted from the liquid adsorption (LAC) to the size exclusion (SEC) mode. The critical point of adsorption was reached at 91 vol% iso-propanol, where all standards eluted at the same retention time irrespective of their molar mass. Subsequently, these conditions were utilized for the investigation of the influence of the hydrophobicity of the PEtOx end group upon its retention behavior and for analysis of a PEtOx containing block copolymer by liquid chromatography under critical conditions coupled with SEC. Hyphenation with matrix assisted laser desorption ionization time of flight mass spectrometry and electro spray ionization mass spectrometry enabled the assignment of the detected peaks in the chromatograms.

Characterization of poly(2-oxazoline)s by liquid chromatography under critical conditions

243rd National Meeting (2012)

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