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A Pyrolysis – Gas Chromatography – Mass Spectrometry (Py-GC-MS) method was developed for the analysis and profiling of crude and heavy fuel oil asphaltenes, for application in oil fingerprinting. Asphaltenes were precipitated from ten geographically different oils usingn-pentane, and analysed by Py-GC-MS. Alkane profiles and sulphur/aromatic profiles were used to compare the oils, and to correctly differentiate oils from different geographical regions. Py-GC-MS could not differentiate a weathered oil sample and a fresh oil sample from the same source. The results of this study support the findings from a previously developed FTIR method for asphaltene profiling. [ABSTRACT FROM PUBLISHER]

Oil fingerprinting is concerned with determining the chemical profile of a spilled oil to determine its origin, whether that be a vessel, well or other source. Asphaltenes are typically discarded in this process even though they are considered refractory in comparison to the volatile fraction and have the ability to provide valuable information in oil fingerprinting. A heavy fuel oil was exposed to evaporative and photochemical conditions to determine if the asphaltene fraction and asphaltene profiling were influenced by weathering. It was found that although evaporative weathering had a strong effect on the volatile fraction of the oil, it had no influence on the asphaltene fraction, and profiling of the asphaltene fraction using previously published methods was still possible. When the oil was exposed to photo-oxidative conditions using natural sunlight, the mass of the asphaltene fraction increased significantly. Attenuated Total Reflectance - Fourier Transform Infrared (ATR-FTIR) analysis demonstrated that the oxygen level in the asphaltene fraction also increased with photochemical weathering compared to evaporative weathering alone. Even though the asphaltene fraction changed under photo-oxidative conditions, it could still be used for source determination using previously published ATR-FTIR and pyrolysis GC-MS methods for profiling of the asphaltene fraction. [ABSTRACT FROM AUTHOR]