Detection of Environmental Contaminants Caused by the Oil Spill in the Gulf of Mexico by GC and HPLC
Poster May 25, 2011
Sky Countryman, Ngoc Nguyen, Jeff Layne, Kory Kelly and Zeshan Aqeel
The April 2010 oil spill in the Gulf of Mexico is undeniably the largest oil leak in U.S. history. The objective of this work was to provide analytical methods for analyzing the most common contaminants. Several rapid cleanup procedures utilizing SPE or GPC followed by analysis with GC-FID, GC/MS or HPLC were developed for detecting Polycyclic Aromatic Hydrocarbons (PAHs) and other Petroleum Hydrocarbons.
Total petroleum content in aqueous samples was determined by GC and classified by boiling point range: gasoline range (GRO), diesel range (DRO), or oil range organics (ORO).
The nature of some of the early samples collected suggested that it was composed of extremely high molecular weight materials with boiling ranges in the ORO. These samples require the use of specialized metal GC columns that are capable of withstanding temperatures above 430 °C. Methodologies are presented to characterize hydrocarbon samples that contain species higher than C120.
Traditional approaches to hydrocarbon testing provide a sum of the hydrocarbon material present in the sample but make no distinction between the types of hydrocarbons. While these methods give a general understanding of the sample, they do not accurately describe its toxic potential. To give a more accurate assessment of sample toxicity, samples are fractionated using a silica gel SPE cartridge into an aromatic and an aliphatic portion. The fractions are then run separately by GC-FID and the level of specific compounds that are known to be toxic can be measured. An alternative procedure of extracting PAH isomers from water using solid phase extraction (SPE) followed by analysis by GC/MS is also demonstrated.