FT-ICR MS analysis of asphaltenes: Asphaltenes go in, fullerenes come out

• Published in: Fuel (Guildford) Vol. 131; pp. 49 - 58
• Main Authors: Pereira, Thieres M.C., Vanini, Gabriela, Tose, Lílian V., Cardoso, Felipe M.R., Fleming, Felipe P., Rosa, Paulo T.V., Thompson, Christopher J., Castro, Eustáquio V.R., Vaz, Boniek G., Romão, Wanderson
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2014; Elsevier
• Subjects: Applied sciences; Asphaltenes; Buckminsterfullerene; Clusters; Density; Dispersions; Energy; Energy. Thermal use of fuels; Exact sciences and technology; FT-ICR MS; Fuels; Fullerene clusters; Fullerenes; Ionization source; Lasers; Petroleomics; Plumes; Asphaltenes; Ionization source; Fullerene clusters; FT-ICR MS; Petroleomics; Asphaltene; Ionization; Fullerenes
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/j.fuel.2014.04.049

•We describe FT-ICR MS analysis of asphaltene using different ionization sources.•LDI/MALDI facilitated clustering reactions to form characteristic fullerene ions.•The clusterization of asphaltenes showed a dependency on the laser power density.•APCI/APPI should be more suitable to access the chemical composition of asphaltene.
Asphaltenes analysis still remains a challenge due to their unknown molecular structure and self-associative behavior. FT-ICR MS analyses using five different ionization methods, ESI, APCI, APPI, LDI and MALDI, in both positive and negative mode were performed. A characteristic and typical behavior was observed for the experiments using LDI(±) and MALDI(±)FT-ICR analyses: a broadband mass spectrum ranging from m/z 500 to 3000 was observed with a 24Da interval. This phenomenon was attributed to fullerene cluster formation. The most abundant allotropic form of fullerene, C60, was observed at m/z 719.99914. These species were not observed in APCI(+)/APPI(+) analyses. This last analysis of asphaltene samples doped with the C60 solution promptly reveals the typical fullerene ions. LDI(+) analyses of pure C60 showed condensation products. These results indicate a clusterization of asphaltenes in the LDI/MALDI plume, which showed a highly dependency on the laser power density. The dispersion of LDI results on carbonaceus samples in the literature is associated with the lack of control of these parameters. However, to access the sample composition, APPI and APCI should be more suitable.