Gas chromatography-isotope ratio mass spectrometry-A novel approach for monitoring the origin and fate of hydrocarbon contaminants in the environment

EPA Grant Number: R826178
Title: Gas chromatography-isotope ratio mass spectrometry-A novel approach for monitoring the origin and fate of hydrocarbon contaminants in the environment
Investigators: Philp, R. Paul
Current Investigators: Philp, R. Paul , Kuder, T. , Smallwood, B.
Institution: University of Oklahoma
EPA Project Officer: Lasat, Mitch
Project Period: October 1, 1997 through September 30, 2000
Project Amount: $313,743
RFA: Exploratory Research - Environmental Chemistry (1997) RFA Text |  Recipients Lists
Research Category: Water , Land and Waste Management , Air , Engineering and Environmental Chemistry


Correlation of hydrocarbon contaminants with suspected sources is a formidable task, particularly for weathered samples. GC and GCMS can produce ambiguous results when correlating weathered and unweathered samples. This project will investigate using gas chromatography-isotope ratio mass spectrometry(GCIRMS) to determine the isotopic composition of individual compounds for correlation purposes. Preliminary results have shown the isotopic composition of resolvable individual compounds remain virtually unaffected by weathering. Isotopic values are additive-thus if two gasoline samples commingle, a mixing model can be developed to determine the relative proportions of the two gasolines in the mixture. GCIRMS will also be investigated to monitor hydrocarbons in wildlife, and correlating them with a specific spill.


Crude oils and hydrocarbon products will be weathered and analyzed by GC, GCMS, and GCIRMS before and after weathering, to determine changes resulting from weathering. Asphaltenes will be isolated from severely biodegraded samples, pyrolysed and isotopic compositions of the individual compounds determined as an alternative method for correlating purposes. Laboratory studies will be undertaken with individual gasolines, and mixtures of gasolines in varying proportions, to illustrate that isotopic values for the individual compounds are additive. Investigation of oxygenated additives will increase the specificity since different suppliers may use a common gasoline source but the additives may be company specific. Wildlife samples affected by oil spills will be analysed to determine if any recovered hydrocarbons can be linked to a specific spill on the basis of the GCIRMS data.

Expected Results:

Preliminary data have indicated that GCIRMS has potential for monitoring the origin and fate of hydrocarbons in the environment. Examination of more extensively degraded samples will support this conclusion and permit development of a routine GCIRMS procedure, in conjunction with GC and GCMS. Development of mixing models based on isotopic compositions of individual compounds in gasoline samples will provide a useful tool for determining the composition of mixtures resulting from leaking storage tanks. The key to all of these experiments is based on the fact that preliminary results have shown that isotopic compositions of individual compounds do not change significantly with weathering and secondly contaminants such as gasoline that may have virtually identical GC and GCMS fingerprints can be discriminated on the basis of their isotopic compositions.

Publications and Presentations:

Publications have been submitted on this project: View all 13 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

analytical, environmental chemistry, hydrocarbons, carbon isotopes, MTBE, oil spills, correlation, weathering., Scientific Discipline, Air, Waste, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Environmental Chemistry, Chemistry, Fate & Transport, Ecological Risk Assessment, Engineering, Chemistry, & Physics, Biology, fate and transport, gasoline, hydrocarbon, mass spectrometry, MTBE, isotope ratio, gas chromatography, chemical kinetics, isotope ratio mass spectrometry, oil spills, weathering, analytical models

Progress and Final Reports:

  • 1998
  • 1999 Progress Report
  • Final Report