Efficient Structural Characterization of Poly(Methacrylic Acid) by Activated-Electron Photodetachment Dissociation |
| |
Authors: | Marion Girod Claire Brunet Rodolphe Antoine Jérôme Lemoine Philippe Dugourd Laurence Charles |
| |
Institution: | 1.Université de Lyon,Villeurbanne cedex,France;2.CNRS and Université Lyon I,Laboratoire de Spectrométrie Ionique et Moléculaire, UMR 5579,Villeurbanne cedex,France;3.CNRS and Université Lyon I,Institut des Sciences Analytiques, UMR 5380,Villeurbanne cedex,France;4.Laboratoire Chimie Provence, Spectrométries Appliquées à la Chimie Structurale,Aix-Marseille University – CNRS, UMR 6264,Marseille Cedex 20,France |
| |
Abstract: | Characterization of end-groups in poly(methacrylic acid) (PMAA) was achieved using tandem mass spectrometry after activated-electron
photodetachment dissociation (activated-EPD). In this technique, multiply deprotonated PMAA oligomers produced in the negative-ion
mode of electrospray ionization were oxidized into radical anions upon electron photodetachment using a 220 nm laser wavelength,
and further activated by collision. In contrast to conventional collision induced dissociation of negatively charged PMAA,
which mainly consists of multiple dehydration steps, fragmentation of odd-electron species is shown to proceed via a radical-induced
decarboxylation, followed by reactions involving backbone bond cleavages, giving rise to product ions containing one or the
other oligomer termination. A single radical-induced mechanism accounts for the four main fragment series observed in MS/MS.
The relative position of the radical and of the anionic center in distonic precursor ions determines the nature of the reaction
products. Experiments performed using PMAA sodium salts allowed us to account for relative abundances of product ions in series
obtained from PMAA, revealing that ion stability is ensured by hydrogen bonds within pairs of MAA units. |
| |
Keywords: | |
本文献已被 PubMed SpringerLink 等数据库收录! |
|