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Such a strategy allows for the quantitative measurement of a large number of gasoline-range (volatile) and diesel range (semi-volatile) hydrocarbons and non-hydrocarbons.

In gasoline investigations this involves measurement of nearly one hundred of the so-called “PIANO” compounds (paraffins, iosparaffins, aromatics, naphthenes, olefins), oxygenates, alkyl lead additives, halogenated lead scavangers, and volatile sulfur compounds.

Definitive answers to these questions are not always achieved through forensic investigations, but combining chemical fingerprinting with other types of forensic data, including an understanding of the site-specific geologic and hydrogeologic conditions and operational and regulatory histories for the site, can produce highly effective and defensible arguments (Stout et al., 1998).

Both gasolines met the Federal RFG requirements, the American Society for Testing and Materials (“ASTM”) requirements, and the performance requirements, yet each exhibits distinct hydrocarbon distributions.The following case study illustrates the effectiveness of this method for fingerprinting gasoline: The objective of this investigation was to determine if a non-aqueous phase liquid (NAPL) encountered under a street separating two service stations was correlated to free-phase gasolines on either of the two adjacent service station properties.Detailed analysis was conducted on free-phase gasoline product samples from each property and on the NAPL from beneath the street (Figure 3).The relative absence of the Station B iso-paraffins in the ‘Street’ NAPL indicated it was not consistent with the gasoline from Station B; therefore, Station A is the likely source of the NAPL.Diesel fuel #2 used in on-road vehicles belong to the distillate family of fuels.For example, the polycyclic aromatic hydrocarbons (PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds measured using standard US EPA methods (i.e., methods 82) typically make up less than five to eight percent of the total PAHs and volatile chemicals in most petroleum products, and as such the data have, at best, limited diagnostic value (Douglas and Uhler, 1993).

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