Systematic MALDI-TOF CID Investigation on Different Substituted mPEG 2000
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Knop, Katrin; Jahn, Burkhard O.; Hager, Martin D.; Crecelius, Anna; Gottschaldt, Michael; Schubert, Ulrich S.
- Abstract:
- Methoxy poly(ethylene glycol) 2000 (mPEG 2000) samples were substituted via esterification
reactions to convert the hydroxyl end group of the mPEG into potential initiators for the
cationic ring opening polymerization of 2-oxazolines. These substitution products were
investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
(MALDI-TOF MS); in addition, detailed MALDI-TOF/TOF-collision induced dissociation (CID) MS
studies were performed to introduce this method as complementary structural characterization
tool allowing the detailed analysis of the prepared macromolecules. The CID of the
macroinitiators revealed 1,4-hydrogen and 1,4-ethylene eliminations forming very regular
fragmentation patterns which showed, depending
on the end groups, different fragmentation series.
Furthermore, very pronounced McLaffertyĆ¾1
rearrangements (1,5 hydrogen-transfer) of the
introduced ester end groups were observed
leaving the mPEG molecule as neutral acid. This
incisive loss revealed the exact molar mass for
each end group and, therefore, represents an
important tool for end group determination of
functionalized polymers.
- Year:
- 2010
- Type of Publication:
- Article
- Journal:
- Macromolecular Chemistry and Physics
- Volume:
- 211
- Pages:
- 677 - 684