Laboratory Analysis for Petroleum Hydrocarbons

EPA method 8015 is one of the most commonly used analytical methods in determining the extent of total petroleum hydrocarbons (TPH) impacts on soil and groundwater, specifically diesel range organics (DROs) and gasoline range organics (GROs). This method is often employed for leaking underground storage tank (LUST) sites or other characterization sites and is used to determine the concentration of semi volatile organic compounds and various non halogenated volatile organic compounds by gas chromatography using flame ionization detection. Diesel range organics correspond to the range of alkanes with carbon chains from C10-C28 and cover a boiling point range of approximately 170 degrees C to 430 degrees C. Gasoline range organics correspond to the lighter alkanes with carbon chains from C6- C10 with a boiling point range of approximately 60 degrees C to 170 degrees C.

tph
Graphic from Brewer et al. (Risk-Based Evaluation of Total Petroleum Hydrocarbons in Vapor Intrusion Studies. International Journal of Environmental Research and Public Health. June 13, 2013.

EPA method 8015M is a known modification of Method 8015B which provides an analysis of motor oil range organics.  Motor oil range organics correspond to the range of alkanes with carbon chains from C28-C35.  Silica gel cleanup is sometimes included in Method 8015. Scientific investigation has shown that the analytical signature of water-soluble petroleum hydrocarbons should be composed of discrete peaks and should not have an unresolved complex mixture or “hump” in the chromatogram. These humps can be resolved by doing a silica gel filtration of the sample. Our testing is done reliably and expeditiously at Performance Analytical Laboratories Inc. located in Signal Hill (pali-labs.com). For more information on this procedure, please see the EPA science inventory webpage on TPH.

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