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Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators.
MedLine Citation:
PMID:  19819723     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
Nine polyisobutylene (PIB) derivatives with different end groups (chlorine, vinyl, isobutenyl, 2,2-diphenylvinyl, and carboxyl) and molecular weights (1000 to 4500 g/mol), initiated by monofunctional and aromatic bifunctional initiators were studied by atmospheric pressure photoionization mass spectrometry (APPI-MS) in both negative and positive ion modes. Consistent with previous findings, negative ion APPI-MS revealed end-group identities through the formation of PIB adducts with chloride ions formed in situ from a chlorinated solvent (e.g., CCl4) in the presence of a dopant (toluene). In positive ion mode, considerable fragmentation of these PIB derivatives was observed, rendering end-group determinations very difficult. The M(n) values obtained by APPI(-)-MS were considerably lower than those determined by SEC for PIB derivatives with M(n) higher than 2000 g/mol. PIBs containing carboxyl termini can undergo collision-induced dissociation, yielding structurally important product ions. The resulting APPI-MS/MS intensities were found to reflect the "arm-length" distribution for PIBs with bifunctional aromatic moieties. In positive ion mode, [M + COCl]+ adducts were observed for PIBs with an aromatic initiator moiety. The origin of the COCl+ species is also discussed.
Authors:
Lajos Nagy; Vikt??ria P??lfi; Mijid Narmandakh; Akos Kuki; Andrea Ny??ri; B??la Iv??n; Mikl??s Zsuga; S??ndor K??ki
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Publication Detail:
Type:  Journal Article     Date:  2009-09-12
Journal Detail:
Title:  Journal of the American Society for Mass Spectrometry     Volume:  20     ISSN:  1879-1123     ISO Abbreviation:  J. Am. Soc. Mass Spectrom.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-11-25     Completed Date:  2010-02-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9010412     Medline TA:  J Am Soc Mass Spectrom     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2342-51     Citation Subset:  -    
Affiliation:
Department of Applied Chemistry, University of Debrecen, Debrecen, Hungary.
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