Characterization Tool For Poly(2-Oxazoline)s, ESI-Q-TOF MS/MS (Electrospray Ionization Quadruple Time-Of-Flight Mass Spectrometry)

Electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) has been used for the detailed characterization of poly(2-oxazoline)s. The ESI-Q-TOF MS/MS studies were performed to evaluate this method as structural characterization tool for poly(2-oxazoline)s. Possible fragmentation mechanisms such as 1,4-hydrogen and ethene elimination, as well as McLafferty rearrangement, were proposed for the obtained fragmentation products. Side group elimination was observed depending on the chemical structure of the repeating units.

Electrospray ionization mass spectrometry (ESI-MS) [1] has become an important tool for the characterization of macromolecules in recent years. ESI-MS allows the ionization of various macromolecules with little or no fragmentation, enabling accurate molar mass determination by making the unfragmented structure amenable to mass separation. Combining ESI-MS to highresolution mass analyzers such as quadrupole-time-offlight (Q-TOF) instrument provides exact molar masses for the polymers analyzed with mass accuracies in the ppm region. Therefore, valuable information on the chemical constitution of the macromolecule can be derived. The interfacing of this soft ionization method with collisioninduced dissociation (CID) presents a powerful technique for the detailed structural characterization of polymers. In the presented study, the aim was to characterize different poly(2-oxazoline)s by using ESI-Q-TOF MS and MS/MS to obtain structural information about these polymers and investigate fragmentation pathways in detail.