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Methylation of acidic moieties in poly(methyl methacrylate‐co‐methacrylic acid) copolymers for end‐group characterization by tandem mass spectrometry
Author(s) -
Giordanengo Rémi,
Viel Stéphane,
Hidalgo Manuel,
AllardBreton Béatrice,
Thévand André,
Charles Laurence
Publication year - 2010
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.4591
Subject(s) - chemistry , copolymer , methacrylic acid , methyl methacrylate , polymer chemistry , monomer , tandem mass spectrometry , methacrylate , mass spectrometry , dissociation (chemistry) , glycidyl methacrylate , polymer , acrylic acid , end group , derivatization , collision induced dissociation , organic chemistry , chromatography
Abstract The complete structural characterization of a copolymer composed of methacrylic acid (MAA) and methyl methacrylate (MMA) units was achieved using tandem mass spectrometry. In a first step, collision‐induced dissociation (CID) of sodiated MAA‐MMA co‐oligomers allowed us to determine the co‐monomeric composition, the random nature of the copolymer and the sum of the end‐group masses. However, dissociation reactions of MAA‐based molecules mainly involve the acidic pendant groups, precluding individual characterization of the end groups. Therefore, methylation of all the acrylic acid moieties was performed to transform the MAA‐MMA copolymer into a PMMA homopolymer, for which CID mainly proceeds via backbone cleavages. Using trimethylsilyldiazomethane as a derivatization agent, this methylation reaction was shown to be complete without affecting the end groups. Using fragmentation rules established for PMMA polymers together with accurate mass measurements of the product ions and knowledge of reagents used for the studied copolymer synthesis, a structure could be proposed for both end groups and it was found to be consistent with signals obtained in nuclear magnetic resonance spectra. Copyright © 2010 John Wiley & Sons, Ltd.