The SDI RaPID Assays for petroleum hydrocarbon fuels (Total BTEX, PAHs) have been shown to provide excellent correlation with GC based (8015M) and IR based (418.1) methodologies for testing Total Petroleum Hydrocarbons (TPH). Linear relationships between immunoassay and TPH results with both gasoline and diesel fuels are demonstrated. Fuel reactivities with immunoassay are shown to vary significantly depending on type and source .
Petroleum derived fuels are complex mixtures of organic compounds, predominantly hydrocarbons, with varying compositions depending on source of the crude oil and its refining process. The chemical characteristics of the these fuels can vary between different brands and grades of fuels and depending on geographical region, commercial source, and season. The current analytical methods developed by the U.S. EPA for compliance monitoring of petroleum products include infrared spectroscopy (418.1), the series 600 methods and the SW-846 8000 series methods. Similar methods for volatile hydrocarbons (C6-C10) and diesel range hydrocarbons (C10-C28) have been developed through the American Petroleum Institute. These methods are commonly called GRO (gasoline range organics) and DRO (diesel range organics) respectively. Results from all these methods may be generically referred to as TPH or 'Total Petroleum Hydrocarbons.' GC/FID procedures like those cited above are popular with many state and local regulatory agencies responsible for administering remediation programs for fuels. Each state may define its own criteria and will often develop its own methodologies. No universally accepted chromatographic procedure for these measurements has been established.