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Mass spectrometry and ion mobility study of poly(ethylene glycol)‐based polyurethane oligomers
Author(s) -
Harris Rachel A.,
Picache Jaqueline A.,
Tomlinson Ian D.,
Zlibut Emanuel,
Ellis Berkley M.,
May Jody C.,
McLean John A.,
Hercules David M.
Publication year - 2020
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8662
Subject(s) - chemistry , oligomer , ethylene glycol , polymer , mass spectrometry , ion , polymerization , polyurethane , tandem mass spectrometry , polymer chemistry , fragmentation (computing) , analytical chemistry (journal) , chromatography , organic chemistry , computer science , operating system
Rationale Commercial‐grade polymer synthesis is performed via melt polymerization, which leads to polydispersion. The work reported herein provides a synthetic strategy to produce mono‐dispersive polyurethane oligomers and an analytical strategy to distinguish these oligomers, providing chemists with the tools necessary to synthesize and identify specific polymer structures that exhibit a desired property. Methods Three isomeric poly(ethylene glycol)–polyurethane (PEG‐PUR) oligomers were synthesized and analyzed via flow‐injection ion mobility mass spectrometry (IM‐MS). Each polymer oligomer was injected and run independently via flow injection at 100 μL•min −1 and analyzed in positive ion mode on a drift tube quadrupole time‐of‐flight (QTOF) instrument. Mobility measurements were determined using a single‐field approach. For tandem mass spectrometry (MS/MS) experiments, the sodium‐adducted singly charged precursor ion was isolated in the quadrupole and subjected to a range of collision energies. Results In MS experiments, both +1 and +2 sodium‐adducted species were observed for each oligomer at m/z 837.4 and 430.2, respectively. When isolated and fragmented via MS/MS, the +1 precursor yielded distinct product ions for each of the three isomeric oligomers. Fragmentation generally occurred at urethane linkages via 1,3‐ and 1,5‐H shift mechanisms. IM was also used to distinguish the three isomers, with greater IM separation observed for the +2 versus the +1 species. Conclusions Mono‐disperse PEG‐PUR oligomers were synthesized and analyzed. Although the polymeric oligomers analyzed in this study are quite small and structurally simple, this work serves as a model system for the synthesis and structural characterization of larger, more complex block copolymers.