Systematic MALDI-TOF CID Investigation on Different Substituted mPEG 2000

Authors

  • Katrin Knop,

    1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany
    2. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands
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  • Burkhard O. Jahn,

    1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany
    2. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands
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  • Martin D. Hager,

    1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany
    2. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands
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  • Anna Crecelius,

    1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany
    2. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands
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  • Michael Gottschaldt,

    1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany
    2. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands
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  • Ulrich S. Schubert

    Corresponding author
    1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany
    2. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands
    3. Laboratory of Macromolecular Chemistry and Nanoscience, Eindhoven University of Technology, Den Dolech 2, 5600 MB Eindhoven, The Netherlands
    • Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, 07743 Jena, Germany. Fax. +49 3641 948 202
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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 McLafferty + 1 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.

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