Abstract:

We explore the analytical capabilities of ramped pyrolysis – gas chromatography – mass spectrometry (Py-GC-MS) to evaluate environmental samples of petroleum hydrocarbons from the Deepwater Horizon oil spill. Specifically, we use a data set of oil sheen, tars and oiled sediments collected on Grand Isle and within Barataria Bay, LA between 2010-2012. We show that bulk flow Py-GC-MS can quantify overall weathering degree, and that thermal slicing Py-GC-MS can quantify specific petroleum hydrocarbons in the “quantification zone”, as well as qualify changes in non-GC amenable petroleum hydrocarbons in the “cracking zone”. Our data also suggests an increase in thermochemical stability, oxygenated products and complexity of resin and asphaltene components with advanced weathering, particularly in oil sheen. This analysis not only elucidates weathering trends with current samples, but also illustrates the analytical capacity of this method for future petroleum hydrocarbon investigations.

Suggested Citation:

Meredith Evans, Zhanfei Liu. 2017. Ramped Pyrolysis - Gas Chromatography - Mass Spectrometry of weathered Deepwater Horizon oil, Grand Isle and Barataria Bay, Louisiana, 2010-2012. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7C82798

Publications:

Seeley, M. E., Wang, Q., Bacosa, H., Rosenheim, B. E., & Liu, Z. (2018). Environmental petroleum pollution analysis using ramped pyrolysis-gas chromatography–mass spectrometry. Organic Geochemistry, 124, 180–189. doi:10.1016/j.orggeochem.2018.07.012

Purpose:

To evaluate the capability of ramped pyrolysis-GC/MS in the analysis of oiled samples.

Data Parameters and Units:

All values in the worksheet represent the area under the chromatogram. Rep: replicate. A, B, C, D, E, F: pyrolysis temperature zones (A=50-90°C; B=90-170°C; C=170-290°C; D=290-370°C; E=370-530°C; F=530-650°C). Each sheet represents a sample (oil sheen, sediment, or tar). The numbers on the name of the sheet indicate the number of days from the spill. Samples were collected on Grand Isle (29.258°N 89.958°W) or Bay Jimmy (29.477°N 89.894°W), Louisiana. Samples collected from Grand Isle include 46 d oil sheen, 88 d sediment, 337 d sediment, and 881 d sediment. Samples collected from Bay Jimmy include 337 d tar, 694 d sediment, and 881 d tar. Sample weight (mg).

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