Recovery of diesel fuel from soil by supercritical fluid extraction–gas chromatography

An analytical method based on CO₂ supercritical fluid extraction (SFE) followed by gas chromatography (GC) was evaluated, compared to Soxhlet extraction, and found to determine accurately and precisely diesel fuel contamination of standard soil samples at a total petroleum hydrocarbon level of 100 μg/g in soil. While both extraction methods have the same 3% relative repeatability standard deviation for determination of total hydrocarbon contamination at this level, SFE requires much less time, uses less organic solvent and provides better recovery of the more volatile n-C₁₀ to n-C₁₂ hydrocarbons.