title: Fullerenes in asphaltenes and other carbonaceous materials: natural constituents or laser artifacts.
abstract: The presence of fullerenes as natural constituents of carbonaceous materials or their formation as laser artifacts during laser desorption ionization (LDI) mass spectrometry (MS) analysis is reinvestigated and reviewed. The results using asphaltene samples with varying composition as well as standard polycyclic aromatic hydrocarbons (PAH) and fullerene samples as models have demonstrated that indeed Cn ring fullerenes are not natural constituents but they are formed as common and often as predominant artifacts upon laser radiation, and a series of incorrect assignments based on LDI-MS data of several carbonaceous materials seems unfortunately to have been made. When the present results are evaluated also in the light of the vast literature on LDI-MS of carbonaceous materials, the formation of fullerene artifacts seems particularly common for LDI-MS analysis of asphaltenes and other carbonaceous samples with considerably high levels of PAH and varies according to the type of laser used, and the intensity of the laser beam.
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, 13083-970, Campinas, SP, Brazil. eberlin@iqm.unicamp.br gsantos.vanessa@gmail.com.
authors.forename: Vanessa G
authors.initials: VG
authors.lastname: Santos
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, 13083-970, Campinas, SP, Brazil. eberlin@iqm.unicamp.br gsantos.vanessa@gmail.com and Division of Chemical Metrology, National Institute of Metrology, Quality and Technology - INMETRO, 25250-020, Duque de Caxias, RJ, Brazil.
authors.forename: Maíra
authors.initials: M
authors.lastname: Fasciotti
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, 13083-970, Campinas, SP, Brazil. eberlin@iqm.unicamp.br gsantos.vanessa@gmail.com.
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Pudenzi
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, 13083-970, Campinas, SP, Brazil. eberlin@iqm.unicamp.br gsantos.vanessa@gmail.com.
authors.forename: Clécio F
authors.initials: CF
authors.lastname: Klitzke
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, 13083-970, Campinas, SP, Brazil. eberlin@iqm.unicamp.br gsantos.vanessa@gmail.com.
authors.forename: Heliara L
authors.initials: HL
authors.lastname: Nascimento
authors.affiliation: CENPES-PETROBRAS, 21941-915, Rio de Janeiro RJ, Brazil.
authors.forename: Rosana C L
authors.initials: RC
authors.lastname: Pereira
authors.affiliation: CENPES-PETROBRAS, 21941-915, Rio de Janeiro RJ, Brazil.
authors.forename: Wagner L
authors.initials: WL
authors.lastname: Bastos
authors.affiliation: ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas, UNICAMP, 13083-970, Campinas, SP, Brazil. eberlin@iqm.unicamp.br gsantos.vanessa@gmail.com.
authors.forename: Marcos N
authors.initials: MN
authors.lastname: Eberlin