SOURCE IDENTIFICATION OF SPILLED DIESEL USING DIAGNOSTIC SESQUITERPANES AND DIAMONDOIDS

Abstract

ABSTRACT Examination of GC-MS chromatograms of bicyclic biomarker sesquiterpanes and diamondoids using their characteristic fragment ions provides another highly diagnostic means for correlation and differentiation of unknown spilled oil samples that are difficult to identify by current fingerprinting techniques. In this work, GC-FID and GC-MS fingerprinting analysis in conjunction with statistical data analysis of target oil hydrocarbons including sesquiterpanes and diamondoids was performed for identification of an unknown oil spill incident occurred in a harbor of the Netherlands in 2004. Forensic investigation included the: (1) identification and characterization of numerous sesquiterpanes and diamondoids; (2) comparison of the distribution of sesquiterpanes and diamondoids; (3) development of a series of diagnostic indices for correlation and differentiation of spilled fuel samples; and (4) use of “Two-tailed” unpaired Student'S t-test to statistically evaluate the imperceptible differences between the selected diagnostic ratios of target compounds in the spill fuel and the suspected source fuel samples. At a 95% confidence interval, 33 of all 38 diagnostic indices (among them, 20 are diagnostic indices of sesquiterpanes and diamondoids) show positive matches between spill sample and suspected source fuel sample 1. In comparison, only 5 of 38 diagnostic indices indicate positive matches between spill sample and suspected source sample 3. These evidences demonstrate that the bunker ship has the responsibility for this oil spill incident.