title: Detailed characterization of poly(2-ethyl-2oxazoline)s by energy variable collision-induced dissociation study.
abstract: BACKGROUND
  Poly(2-oxazoline)s are important polymers and can be considered as pseudo-peptides which makes them important for biomedical and life science applications. This prompts the need for a detailed characterization of these polymers via different analytical tools such as mass spectrometry. Here, the energy-variable collision-induced dissociation (CID) of poly(2-ethyl-2-oxazoline)s was studied by electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-QTOFMS/MS) to gain further structural information about this polymer type.
  
  
  METHODS
  All polymers were analyzed using manual flow injection of samples into an ESI-QTOF mass spectrometer. Mass spectra (MS and MS/MS) were obtained in the positive ion mode over a mass-to-charge (m/z) range from 50 to 3000.
  
  
  RESULTS
  The dependency of the fragmentation patterns as a function of collision energy was examined and the characteristic collision energy (CCE or CE50 ) values for various poly(2-ethyl-2-oxazoline)s with different end-groups were calculated. The effect of molar masses on the CCE values was investigated via the survival yield (SY) method and a linear relationship between CCE values and the degree of polymerization for the PEtOx polymers was observed.
  
  
  CONCLUSIONS
  This study showed that ESI-MS/MS is very useful for differentiating poly(2-ethyl-2-oxazoline)s with different end-groups by varying the collision energy. The SY method has the potential to determine the importance of the end-groups on the fragmentation behavior of this polymer type.
authors.affiliation: Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Jena, Germany.
authors.forename: Esra
authors.initials: E
authors.lastname: Altuntas
authors.forename: Christine
authors.initials: C
authors.lastname: Weber
authors.forename: Ulrich S
authors.initials: US
authors.lastname: Schubert