Dopant-assisted atmospheric pressure photoionization mass spectrometry of polyisobutylene derivatives initiated by mono- and bifunctional initiators |
| |
Authors: | Lajos Nagy Viktória Pálfi Mijid Narmandakh Ákos Kuki Andrea Nyíri Béla Iván Miklós Zsuga Sándor Kéki |
| |
Institution: | 1. Department of Applied Chemistry, University of Debrecen, H-4010 Debrecen, Egyetem ter 1, H-4010, Debrecen, Hungary 2. Institute of Materials and Environmental Chemistry, Chemical Research Center, Hungarian Academy of Sciences, Budapest, Hungary
|
| |
Abstract: | 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. |
| |
Keywords: | |
本文献已被 ScienceDirect SpringerLink 等数据库收录! |
|