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Updated: Jul 13, 2026
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Chemical Analysis of Water-accommodated Fractions of Crude Oil Spills Using TIMS-FT-ICR MS
Published on: March 3, 2017
Numerical methods for comparing fresh and weathered oils by their FTIR spectra
Jianfeng Li1, D Brynn Hibbert, Stephen Fuller
1School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia. jianfeng.li@unsw.edu.au
The Analyst
|July 25, 2007
Summary
Four similarity indices were evaluated for petroleum oil spill source identification using FTIR spectra. First difference-based indices generally performed better, especially for weathered samples, aiding accurate oil spill forensics.
Area of Science:
- Forensic Science
- Analytical Chemistry
- Spectroscopy
Background:
- Petroleum oil spill source identification is crucial for environmental protection and legal accountability.
- Standard test method D3414 provides a framework for oil spill analysis.
- Fourier-transform infrared (FTIR) spectroscopy is a key technique for oil analysis.
Purpose of the Study:
- To investigate and compare the effectiveness of four similarity indices for identifying the source of petroleum oil spills.
- To evaluate the performance of these indices on both fresh and artificially weathered oil samples.
- To determine the reliability of FTIR spectral matching for oil spill forensics under varying weathering conditions.
Main Methods:
- Four similarity indices were tested: first difference correlation coefficient squared, correlation coefficient squared, first difference Euclidean cosine squared, and Euclidean cosine squared.
- FTIR spectra were divided into three regions: fingerprint (900-700 cm(-1)), generic (1350-900 cm(-1)), and supplementary (1770-1685 cm(-1)).
- An artificial weathering procedure was employed to simulate the effects of environmental exposure on oil samples.
Main Results:
- All tested similarity indices could distinguish between replicate and different fresh oil samples.
- First difference-based indices generally outperformed their parent indices for fresh oil samples.
- For weathered oils, Euclidean cosine and correlation coefficients were effective in the fingerprint region, while first difference indices excelled in the generic region.
- Receiver operating characteristic (ROC) curves indicated reliable matching up to 7 days of weathering difference in the fingerprint region.
Conclusions:
- First difference-based similarity indices show improved performance for petroleum oil spill source identification compared to standard indices.
- FTIR spectral analysis, particularly using first difference methods, is a valuable tool for oil spill forensics, even with weathered samples.
- Artificial weathering can enhance the matching of weathered oil samples to their original source, improving forensic accuracy.
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