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Analyzing the solid soot particulates formed in a fuel‐rich flame by solvent‐free matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
Author(s) -
Zhang Wen,
Shao Can,
Sarathy S. Mani
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.8596
Subject(s) - fourier transform ion cyclotron resonance , chemistry , mass spectrometry , ion cyclotron resonance , analytical chemistry (journal) , soft laser desorption , soot , combustion , matrix assisted laser desorption/ionization , desorption , ion , cyclotron , chromatography , organic chemistry , adsorption
Rationale The compositional and structural information of soot particles is essential for a better understanding of the chemistry and mechanism during the combustion. The aim of the present study was to develop a method to analyze such soot particulate samples with high complexity and poor solubility. Methods The solvent‐free sample preparation matrix‐assisted laser desorption/ionization (MALDI) technique was combined with the ultrahigh‐resolution Fourier transform ion cyclotron resonance (FTICR) mass spectrometry (MS) for the characterization of solid soot particulates. Moreover, a modified iso‐abundance plot (Carbon Number vs. Hydrogen Number vs. Abundance) was introduced to visualize the distributions of various chemical species, and to examine the agreement between the hydrogen‐abstraction‐carbon‐addition (HACA) mechanism and the polycyclic aromatic hydrocarbon growth in the investigated flame system. Results This solvent‐free MALDI method enabled the effective ionization of the solid soot particulates without any dissolving procedure. With the accurate m/z ratios from FTICR‐MS, a unique chemical formula was assigned to each of the recorded mass signals. The combustion products were proven to be mainly large polycyclic aromatic hydrocarbons (PAHs), together with a small amount (<5%) of oxidized hydrocarbons. Conclusions The developed method provides a new approach for the molecular characterization of soot particulates like carbonaceous materials. The investigated soot particulates are mainly PAHs with no or very short aliphatic chains. The growth mechanism of PAHs during combustion can be examined against the classic HACA mechanism.