Separation and measurement of flame‐formed high molecular weight polycyclic aromatic hydrocarbons by size‐exclusion chromatography and laser desorption/ionization time‐of‐flight mass spectrometry
- 7 March 2006
- journal article
- research article
- Published by Wiley in Rapid Communications in Mass Spectrometry
- Vol. 20 (7) , 1104-1108
- https://doi.org/10.1002/rcm.2419
Abstract
The partial contribution of polycyclic aromatic hydrocarbons (PAH), capable of being detected by gas chromatography (GC‐PAH), both to the total mass of the extractable organic fraction of flame‐formed carbon particulates and to its UV‐visible absorption and fluorescence spectra, has been determined by previous work. This contribution indicates the presence of PAH of molecular weight (MW) greater than 400 Da not accessible to conventional analysis. The detection of species in this higher MW range is important for both their potential toxicology and their possible role in soot formation. In the present work extracts of soots have been analyzed by linear mode laser desorption/ionization time‐of‐flight mass spectrometry (LDI‐TOF‐MS) to extend the MW range that can be analyzed beyond the GC‐PAH. The results have been compared with both analysis by reflector mode LDI‐TOF‐MS and the MW evaluation obtained by SEC analysis, as the shortcomings and advantages of both techniques appear to be complementary. Matching the results from the two techniques could give interesting insights in the molecular mass range between GC‐PAH and the first soot particles (of mass > 2000 Da). Mass spectra in this molecular mass range have been obtained with a main ion sequence spacing of 24 Th and a minor ion sequence also with a spacing of 24 Th but off‐set by 12 Th with respect to the main sequence. The two ion progressions have been interpreted by attributing the predominant peaks mainly to PAH with even‐carbon numbers and the smaller ones to cyclopenta‐fused ring PAH. These distributions indicate the occurrence of two competitive mechanisms in the growth of PAH and soot nucleation, i.e. the addition of acetylene (HACA mechanism) and the incorporation of pentagons by large polycyclic aromatic molecules into their aromatic bonding network. Copyright © 2006 John Wiley & Sons, Ltd.Keywords
This publication has 36 references indexed in Scilit:
- Oligomeric carbon and siloxane series observed by matrix‐assisted laser desorption/ionisation and laser desorption/ionisation mass spectrometry during the analysis of soot formed in fuel‐rich flamesRapid Communications in Mass Spectrometry, 2004
- Matching average masses of pitch fractions of narrow polydispersity, derived from matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry, with the polystyrene calibration of SECJournal of Separation Science, 2003
- Effect of LiBr Addition to 1-Methyl-2-pyrrolidinone in the Size-Exclusion Chromatography of Coal-Derived MaterialsEnergy & Fuels, 1998
- Spectroscopic and compositional signatures of pah-loaded mixtures in the soot inception region of a premixed ethylene flameSymposium (International) on Combustion, 1998
- Effect of polydispersity on the characterization of coal-derived liquids by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: inferences from results for mixtures of polystyrene molecular mass standardsRapid Communications in Mass Spectrometry, 1997
- The effect of temperature on soot inception in premixed ethylene flamesSymposium (International) on Combustion, 1996
- The formation of aromatic carbon in sooting ethylene flamesSymposium (International) on Combustion, 1994
- High mass carbon clusters from aromatic hydrocarbons observed by laser mass spectrometryThe Journal of Physical Chemistry, 1989
- First observation of carbon aggregate ions >C600+ by laser desorption Fourier transform mass spectrometryThe Journal of Physical Chemistry, 1989
- Axial and radial measurements of soot and pah in a light oil flameSymposium (International) on Combustion, 1982