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Tuning block copolymer structural information by adjusting salt concentration in liquid chromatography at critical conditions coupled with electrospray tandem mass spectrometry
Author(s) -
Girod Marion,
Phan Trang N. T.,
Charles Laurence
Publication year - 2009
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.4028
Subject(s) - chemistry , electrospray ionization , electrospray , mass spectrometry , tandem mass spectrometry , adduct , nitroxide mediated radical polymerization , moiety , cationic polymerization , polystyrene , copolymer , end group , polymer chemistry , chromatography , organic chemistry , polymer , radical polymerization
Different cationic adducts of poly(ethylene oxide)/polystyrene block co‐oligomers could be produced by adjusting the salt concentration in the mobile phase using a coupling between liquid chromatography at critical conditions and electrospray ionization mass spectrometry. Formation of doubly lithiated adducts was observed at high LiCl concentration (1 mM) while lowering the salt concentration down to 0.1 mM allowed co‐oligomers to be ionized with both a proton and a lithium. The fragmentation pathways observed to occur upon collision‐induced dissociation of ionized copolymers were shown to be highly dependent on the nature of the cationic adducts. As a result, complementary structural information could be reached by performing MS/MS experiments on different ionic forms of the same co‐oligomer molecule. On one hand, release of the nitroxide end‐group as a radical from [M+2Li] 2+ was followed by a complete depolymerization of the polystyrene block, allowing both this end‐group and the polystyrene segment size to be determined. On the other hand, [M+H+Li] 2+ precursor ions mainly dissociated via reactions involving bond cleavages within the nitroxide moiety, yielding useful structural information on this end‐group. Copyright © 2009 John Wiley & Sons, Ltd.