This data set contains chemical analysis data of asphaltenes from a heavy fuel oil "The FTIR data was obtained using the methods described in Brenden J. Riley, Chris Lennard, Stephen Fuller & Val Spikmans (2016): An FTIR method for the analysis of crude and heavy fuel oil asphaltenes to assist in oil fingerprinting, Forensic Science International, 555-564, http://dx.doi.org/10.1016/j.forsciint.2016.07.018" "The pyrolysis GC-MS data was obtained using the methods described in Brenden J. Riley, Chris Lennard, Stephen Fuller & Val Spikmans (2017): Pyrolysis-GC-MS analysis of crude and heavy fuel oil asphaltenes for application in oil fingerprinting, Environmental Forensics, Vol. 19, No 1, 1 - 13,DOI: 10.1080/15275922.2017.1408163" "The GC-MS data was obtained using the methods described in European Committee for Standardization (CEN). 2012. Oil spill identification? waterborne petroleum and petroleum products?part 2: analytical methodology and interpretation of results based on GC-FID and GC-MS low resolution analyses. Brussels, Belgium, no. CEN/TR15522-2: 2012" Treatment samples were exposed to evaporation and photo-oxidation Control samples were exposed to evaporation only and not photo-oxidation Fresh samples were unweathered HFO