Source Characterization of Polycyclic Aromatic Hydrocarbons by Using Their Molecular Indices: An Overview of Possibilities - Reviews of Environmental Contamination and Toxicology - page 74

Spilled oil samples

Extraction

Extract

Clean up & fraction

Tier I

GC - FID

Compare with suspected sources

1. Chromalograms and n-alkane
distribution different?
2 . Diagnostic ratios match?

YES NO

Differences possibly
caused by weathering?

YES

NO

Tier II GC - MS

YES NO

PAH and biomarker patterns
different?

Difference possibly caused
by weathering?

YES

NO WEATHERING CHECK

Tier III

1. Isomar patterns match ?
2. Diagnostic ratios of
“source-specific markers” match ?

YES NO

Difference caused
by weathering?

YES

POSITIVE MATCH NO MATCH

Fig. 6 Oil spill identification protocol. If significant differences in hydrocarbon fingerprints and
diagnostic ratios are found at any stage during the identification process, the conclusion will be that
the samples are not from the suspected source. From Wang et al. ( 1999a ) (modified decision chart
of Nordtest Method 1991 ), with permission, © Elsevier Science BV