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Direct analysis in real time mass spectrometry (DART‐MS) of highly non‐polar low molecular weight polyisobutylenes
Author(s) -
Nagy Lajos,
Nagy Tibor,
Deák György,
Kuki Ákos,
Antal Borbála,
Zsuga Miklós,
Kéki Sándor
Publication year - 2015
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.3621
Subject(s) - chemistry , adduct , mass spectrometry , tandem mass spectrometry , ion , dart ion source , fragmentation (computing) , mass spectrum , deprotonation , polyatomic ion , analytical chemistry (journal) , chlorine , dissociation (chemistry) , polymer chemistry , organic chemistry , electron ionization , chromatography , computer science , ionization , operating system
Low molecular weight polyisobutylenes (PIB) with chlorine, olefin and succinic acid end‐groups were studied using direct analysis in real time mass spectrometry (DART‐MS). To facilitate the adduct ion formation under DART conditions, NH 4 Cl as an auxiliary reagent was deposited onto the PIB surface. It was found that chlorinated adduct ions of olefin and chlorine telechelic PIBs, i.e. [M + Cl] − up to m/z 1100, and the deprotonated polyisobutylene succinic acid [MH] − were formed as observed in the negative ion mode. In the positive ion mode formation of [M + NH 4 ] + , adduct ions were detected. In the tandem mass (MS/MS) spectra of [M + Cl] − , product ions were absent, suggesting a simple dissociation of the precursor [M + Cl] − into a Cl − ion and a neutral M without fragmentation of the PIB backbones. However, structurally important product ions were produced from the corresponding [M + NH 4 ] + ions, allowing us to obtain valuable information on the arm‐length distributions of the PIBs containing aromatic initiator moiety. In addition, a model was developed to interpret the oligomer distributions and the number average molecular weights observed in DART‐MS for PIBs and other polymers of low molecular weight. Copyright © 2015 John Wiley & Sons, Ltd.