Petroleum biomarkers in oiled samples collected in the Gulf of Mexico 2010 - 2012

Analysis of petroleum biomarker was used to identify Macondo Well (MW) oil in samples collected in the Gulf of Mexico. To this end, oiled samples were collected in the Gulf of Mexico during April 2010 through August 2012. This sample set comprises MW oil collected from the well on June 21, 2010, surface slicks and oiled floating Deepwater Horizon debris samples collected on the sea surface during the spill, and samples washed on beaches (oil-soaked sand samples or “sand patties”, oil samples scraped off rocks or “rock scrapings”, and sand-free asphalt pieces “tar balls”). Sand patties, rock scrapings, and asphalt pieces were extracted in dichloromethane (DCM) and methanol (90/10 v/v). All samples were dissolved in DCM or DCM/methanol at concentrations of 10−50 mg mL−1 for analysis on GCxGC-FID (two-dimensional comprehensive gas chromatography with flame ionization detector).