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Thermal desorption and pyrolysis direct analysis in real time mass spectrometry for qualitative characterization of polymers and polymer additives
Author(s) -
Cody Robert B.,
Fouquet Thierry N.J.,
Takei Chikako
Publication year - 2020
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.8687
Subject(s) - dart ion source , chemistry , mass spectrum , thermal desorption , mass spectrometry , polymer , analytical chemistry (journal) , dart , time of flight mass spectrometry , desorption , pyrolysis , secondary ion mass spectrometry , ion , chromatography , organic chemistry , ionization , electron ionization , programming language , adsorption , computer science
Rationale Direct analysis in real time mass spectrometry (DART‐MS) provides qualitative information about additives and polymer composition. However, the observed mass spectra are dependent on sampling conditions, in particular the DART gas temperature. This report describes the combination of a heated sample stage with DART‐MS for polymer characterization. Methods Industrial polymers with different compositions were examined by thermal desorption and pyrolysis (TDPy) DART. Samples were heated on disposable copper stages from ambient temperature to 600°C, and the evolved gases were introduced directly into a DART ion source through a glass tee. Time‐ and temperature‐dependent mass spectra were acquired using a high‐resolution time‐of‐flight mass spectrometer. Kendrick mass analysis was applied to the interpretation of complex mass spectra observed for fluorinated polymers. Results Positive‐ion DART mass spectra of common polymers exhibited peak series differing by monomer masses, often accompanied by a peak corresponding to the protonated monomer. Even polymers that did not exhibit a clear series of peaks produced characteristic mass spectra. Positive‐ion and negative‐ion mass spectra were recorded for fluorinated polymers, with polytetrafluoroethylene (PTFE) producing only negative ions. Thermal desorption provided characteristic temperature profiles for volatile species such as polymer additives and polymer pyrolysis products. Conclusions In comparison with direct analysis by positioning sample directly in the heated DART gas stream, TDPy DART provides a more versatile sampling method and provides thermal separation and profiling of polymer additives, intact short polymer chains, and pyrolysis fragments.