title: Structural determination by atmospheric pressure photoionization tandem mass spectrometry of some compounds isolated from the SARA fractions obtained from bitumen.
abstract: We have identified compounds obtained from the SARA fractions of bitumen by using atmospheric pressure photoionization mass spectrometry and low-energy collision tandem mass spectrometric analyses with a QqToF-MS/MS hybrid instrument. The identified compounds were isolated from the maltene saturated oil and the aromatic fractions of the SARA components of a bitumen. The QqToF instrument had sufficient mass resolution to provide accurate molecular weight information and to enhance the tandem mass spectrometry results. The APPI-QqToF-MS analysis of the separated compounds showed a series of protonated molecules [M + H](+) and molecular ions [M](+▪) of the same mass but having different chemical structures, in the maltene saturated oil and the aromatic SARA fractions. These isobaric ions were a molecular ion [M2 ](+▪) at m/z 418.2787 and a protonated molecule [M5 + H](+) at m/z 287.1625 in the saturated oil fraction, and molecular ions [M6 ](+▪) at m/z 418.1584 and [M7 ](+▪) at m/z 287.1285 in the aromatic fraction. The identification of this series of chemical compounds was achieved by performing CID-MS/MS analyses of the molecular ions [M](+▪) ([M1 ](+▪) at m/z 446. 2980, [M2 ](+▪) at m/z 418.2787, [M3 ](+▪) at m/z 360.3350 and [M4 ](+▪) at m/z 346.2095) in the saturated oil fraction and of the [M5 + H](+) ion at m/z 287.1625 also in the saturated oil fraction. The observed CID-MS/MS fragmentation differences were explained by proposed different breakdown processes of the precursor ions. The presented tandem mass spectrometric study shows the capability of MS/MS experiments to differentiate between different classes of chemical compounds of the SARA components of bitumen and to explain the reasons for the observed mass spectrometric differences. However, greater mass resolution than that provided by the QqToF-MS/MS instrument would be required for the analysis of the asphaltene fraction of bitumen.
authors: Compagnie Industrielle de la Matière Végétale (CIMV), 134 Rue Danton, 92300, Levallois-Perret, France.
authors: Nadine
authors: N
authors: Tachon
authors: Farid
authors: F
authors: Jahouh
authors: Michel
authors: M
authors: Delmas
authors: Joseph H
authors: JH
authors: Banoub
mesh_terms: D006838:Hydrocarbons / Q000737:chemistry*; D015394:Molecular Structure; D010578:Petroleum / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D006838:Hydrocarbons; D010578:Petroleum