Structural Characterization of Methylenedianiline Regioisomers by Ion Mobility-Mass Spectrometry, Tandem Mass Spectrometry, and Computational Strategies. 3. MALDI Spectra of 2-Ring Isomers
| Autor: | Tiffany M. Crescentini, John A. McLean, Jay G. Forsythe, Sarah M. Stow, David M. Hercules, Jody C. May |
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| Rok vydání: | 2017 |
| Předmět: |
Electrospray
Aniline Compounds Molecular Structure Methylene diphenyl diisocyanate 010401 analytical chemistry Stereoisomerism Molecular Dynamics Simulation 010402 general chemistry Tandem mass spectrometry Mass spectrometry 01 natural sciences Medicinal chemistry Mass Spectrometry Article 0104 chemical sciences Analytical Chemistry Ion Matrix (chemical analysis) chemistry.chemical_compound chemistry Desorption Ion Mobility Spectrometry Structural isomer Density Functional Theory |
| Zdroj: | Analytical Chemistry. 89:9900-9910 |
| ISSN: | 1520-6882 0003-2700 |
| DOI: | 10.1021/acs.analchem.7b02133 |
| Popis: | Characterization of methylenedianiline (MDA) 2-ring isomers (2,2′-, 2,4′- and 4,4′-MDA) is reported using matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS), a common technique used for characterizing synthetic polymers. MDA is a precursor to methylene diphenyl diisocyanate (MDI) a hard block component in polyurethane (PUR) synthesis. This manuscript focuses on comparing MALDI results to those of our previous electrospray ionization-mass spectrometry (ESI-MS) studies. In ESI, 2-ring MDA isomers formed single unique [M+H]+ (199 Da) parent ions, whereas in MALDI each isomer shows significant formation of three precursor ions: [M−H]+ = 197 Da, [M·]+ = 198 Da, and [M+H]+ = 199 Da. Structures and schemes are proposed for the MALDI fragment ions associated with each precursor ion. Ion mobility-mass spectrometry (IM-MS), tandem mass spectrometry (MS/MS), and computational methods were all critical in determining the structures for both precursor and fragment ions as well as the fragmentation mechanisms. The present study indicates that the [M−H]+ and [M·]+ ions are formed by the MALDI process, explaining why they were not observed with ESI. |
| Databáze: | OpenAIRE |
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