Regio- and Stereo-Specific Chemical Depolymerization of High Molecular Weight Polybutadiene and Polyisoprene for Their Analysis by High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Comparison with Pyrolysis-Comprehensive Two-Dimensional Gas Chromatography/Mass Spectrometry, Atmospheric Solid Analysis Probe, Direct Inlet Probe-Atmospheric Pressure Chemical Ionization Mass Spectrometry, and Ion Mobility Spectrometry-Mass Spectrometry

Abstract

Polybutadiene (PB) and Polyisoprene (PI) the two most common polydienes (PD), are involved in a large number of materials and used in a wide variety of applications. The characterization of these polymers by mass spectrometry (MS) continues to be very challenging due to their high insolubility and the difficulty to ionize them. In this work, cross-metathesis reaction was used to generate end-functionalized acetoxy ionizable oligomers for the structural deciphering of different commercial PB and PI samples. A cross-metathesis reaction was carried out between polymers and the Z-1,4-diacetoxy-2-butene as chain transfer agent in dichloromethane using Hoveyda-Grubbs second-generation catalyst. Well-defined acetoxy telechelic structures were obtained and analysed by Fourier-Transform ion cyclotron resonance (FTICR) high resolution MS. However, after depolymerization, low molar mass polyolefins contained some units with different configurations, suggesting an olefin isomerization reaction due to the decomposition of the catalyst. The addition of an electron-deficient reagent such as 2,6-dichloro-1,4-benzoquinone suppressed this isomerization in the case of both Z-and E-PB and PI. Ion-mobility spectrometry-mass spectrometry (IMS-MS) and energy resolved tandem mass spectrometry (ERMS) analyses confirmed a successful isomerization suppression. For comparing the results obtained by depolymerisation with classical methods for polymer analysis, pyrolysis-comprehensive two-dimensional gas chromatography/mass spectrometry (Py-GC×GC-MS), atmospheric solid analysis probe (ASAP) and DIP-APCI analyses were performed on the same polymers. This strategy can be applied on a variety of synthetic and natural not yet characterized polymers. File list (2) download file view on ChemRxiv Ziad Mahmoud.pdf (883.65 KiB) download file view on ChemRxiv Ziad_Mahmoud_SI.pdf (1.04 MiB)

Rapid Single Particle Atmospheric Solids Analysis Probe-Mass Spectrometry for Multimodal Analysis of Microplastics

“…Previously, ASAP-MS was shown to be able to ionize both polymers having a low proton affinity, such as PE 27 and PP, 25 , 32 and other nonpolar polymers, 26 e.g., PS. 28 The same was applied to single particle MP analyses of PE, PP, and PS in this study, without the addition of any salt to promote ionization ( Figures S1–S3 ).…”

“…Atmospheric solids analysis probe (ASAP) MS showed promising results in the past for the analysis of synthetic polymers − but, to our knowledge, has never been evaluated for the analysis of MPs. ASAP-MS enables the analysis of solid and liquid samples that are deposited on a probe and inserted directly into the ionization chamber.…”

Direct Mass Spectrometric Analysis of Brominated Flame Retardants in Synthetic Polymers

“…Common analysis techniques for polymers and plastics include thermal analysis (e.g., thermogravimetric analysis and differential scanning calorimetry), spectroscopic techniques (nuclear magnetic resonance, infrared, and Raman spectroscopy), and chromatography (e.g., gel permeation chromatography). − Mass spectrometry (MS) is often utilized in determining polymer molecular weight, polydispersity, heterogeneity, and the presence of additives or degradation products. The most common ionization techniques used in polymer analysis are matrix-assisted laser desorption/ionization (MALDI), atmospheric pressure chemical ionization (APCI), and electrospray ionization (ESI), all of which have their own advantages and limitations. ,− …”

“…The most common ionization techniques used in polymer analysis are matrix-assisted laser desorption/ionization (MALDI), atmospheric pressure chemical ionization (APCI), and electrospray ionization (ESI), all of which have their own advantages and limitations. 6 , 10 − 12 …”

Analysis of Thermoplastic Copolymers by Mild Thermal Degradation Coupled to Ion Mobility Mass Spectrometry

“…[28] The analytical information gained by ASAP-MS is substantially enhanced if MS is coupled with ion mobility (IM) spectrometry, to separate the ions formed not only by the mass-to-charge ratio (m/z) but also by size and shape, and with MS/MS, to confirm or elucidate the primary structures of specific ions based on their fragmentation products. [30] The ASAP-MS and ASAP-IM-MS strategies have been applied to analyze low-polarity and/or high molecular weight polymers, polymer blends, and copolymers; [31][32][33][34][35][36] heavy petroleum fractions; [37] additives; [38,39] particulate matter; [40,41] and crosslinked hydrogels. [42] In this work, we present the first application of ASAP-IM-MS (MS/MS) to multicomponent industrial elastomers, focusing on polyurethane and styrenic copolymers, [43] and document the ability of this methodology to provide fast and sensitive characterization via interfaced desorption/degradationseparation-fragmentation-mass analysis, all performed in the mass spectrometer with no sample preparation ("top-down" strategy).…”