title: Photodegradation of crude oil: liquid injection and headspace solid-phase microextraction for crude oil analysis by gas chromatography with mass spectrometer detector.
abstract: The fate of crude oil under irradiation is studied. After UV irradiation, the fraction present in the highest percentage shifts from the C8-C9 fractions to C13, using gas chromatography-mass spectrometry (GC-MS) analysis in solution. An increase of the relative amount of the C13-C25 fraction is observed, while a decrease in the relative amount of the C7-C12 fractions is present. In headspace solid-phase microextraction (HS-SPME) analysis, the C8-C10 fractions represent 53% of all the compounds detected. A decrease in the relative amount of the C8-C10 fractions is observed, while C11-C15 fractions increase. The irradiation of crude oil with a solar simulator gives a mixture the analysis of which using GC-MS in solution furnishes the same type of results: the relative amounts of linear alkanes and aromatic compounds increase, while a sharp decrease in the relative amounts of branched and cyclic alkanes is observed. In the SPME analysis, a decreased relative amount of branched alkanes and alkenes, and an increase in the relative amounts of cyclic alkanes and aromatic compounds are observed. Analysis of the distribution of the compounds in all the types of compound shows that a dynamic equilibrium between different compounds and different types of compounds is present. To confirm the presence of a dynamic equilibrium, the irradiation of methylcyclohexane in the presence of 2-methylnaphthalene shows the presence in the reaction mixture of a small amount of tetradecane.
authors.affiliation: Dipartimento di Chimica, Università degli Studi della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy. maurizio.dauria@unibas.it
authors.forename: Maurizio
authors.initials: M
authors.lastname: D'Auria
authors.forename: Rocco
authors.initials: R
authors.lastname: Racioppi
authors.forename: Vincenzina
authors.initials: V
authors.lastname: Velluzzi
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D010578:Petroleum / Q000032:analysis* / Q000528:radiation effects*; D010777:Photochemistry; D052617:Solid Phase Microextraction / Q000379:methods*
chemical_list: D010578:Petroleum