OPTIMIZING DETECTION LIMITS FOR THE ANALYSIS OF PETROLEUM HYDROCARBONS IN COMPLEX ENVIRONMENTAL SAMPLES

To evaluate the sources, transport, bioremediation, fate, and effects of spilled petroleum and petroleum products, environmental studies often measure parent and alkylated polycyclic aromatic hydrocarbons (PAH), alkanes, and chemical biomarkers (e.g., triterpanes). Accurate data for low analyte concentrations are required when environmental samples contain hydrocarbons from multiple sources that need to be resolved and quantified. The accuracy and usefulness of the analyses can be improved by lowering the method detection limits (MDLs) for these compounds. Misidentification of hydrocarbon source can result when the MDLs are too high. Modifications to standard analytical methods (i.e., U.S. Environmental Protection Agency Method 8270) can lower MDLs by factors ranging from 10 to 1000. This reduction has important implications for ecological-risk assessments. Modifications having the greatest impact on the MDL include GCMS analysis in the selected-ion-monitoring mode (SIM), increased sample size, column cleanup of the extract, and decreased preinjection volume (volume of final extract prior to injection into instrument). In one study in which a benthic sediment sample was spiked with low levels of topped (heated to remove more volatile PAH that are naturally enriched in crude oil) Alaska North Slope crude, MDLs for individual PAH analytes and biomarkers were determined to be less than 0.5 ng/g (ppb) dry weight and less than 5 ppb dry weight for individual alkanes. Similar results were obtained when the sediment was spiked with the 16 EPA priority pollutants. In addition, a method has been developed to estimate MDLs for source-specific alkylated PAH analytes and chemical biomarker compounds for which standards are not commercially available or are prohibitively expensive. These improved analytical techniques have been used to identity and quantity low levels of hydrocarbons, derived from both natural and anthropogenic sources, found in the benthic sediments of Prince William Sound, AK. (A)

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• Corporate Authors:

  American Chemical Society

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  Washington, DC  United States  20036
• Authors:
  • DOUGLAS, G S
  • BURNS, W A
  • BENCE, A E
  • PAGE, D S
  • BOEHM, P
• Publication Date: 2004-7-1

Language

• English

Media Info

• Features: References;
• Pagination: p. 3958-64
• Serial:
  • Environmental Science & Technology
  • Volume: 38
  • Issue Number: 14
  • Publisher: American Chemical Society
  • ISSN: 0013-936X
  • EISSN: 1520-5851
  • Serial URL: http://pubs.acs.org/journal/esthag

Subject/Index Terms

• TRT Terms: Chemical analysis; Detection and identification; Detectors; Fuels; Hydrocarbons; Pollution; Risk assessment
• Geographic Terms: United States
• ITRD Terms: 7163: Chemical analysis; 9115: Detection; 3850: Fuel; 7367: Hydrocarbon; 2453: Pollution; 9129: Risk assessment; 8122: USA
• Subject Areas: Energy; Environment; Safety and Human Factors;

Filing Info

• Accession Number: 00978184
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Sep 3 2004 12:00AM