Extraction of Petroleum Hydrocarbons from Soil Using Supercritical Argon

• Published in: Analytical chemistry (Washington) Vol. 70; no. 3; pp. 616 - 622
• Main Authors: Liang, Shijiang, Tilotta, David C
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.02.1998
• Subjects: Analytical chemistry; Applied sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Decontamination. Miscellaneous; Exact sciences and technology; Gas chromatographic methods; Gasoline; Hydrocarbons; Petroleum; Pollution; Soil and sediments pollution; Soils; Gas chromatography; Chemical analysis; Multicomponent analysis; Decontamination; Hydrocarbon; Flame ionization detector; Argon; Soil pollution; Supercritical fluid extraction
• ISSN: 0003-2700; 1520-6882
• DOI: 10.1021/ac970983r

The use of supercritical argon is described for the extraction of petroleum hydrocarbons from soil samples. Argon is an attractive solvent because it is inexpensive and inert. Additionally, it has a clear spectral window in the infrared region which makes it useful for on-line (i.e., directly coupled) experiments. Spiking studies conducted with gasoline, no. 1 fuel oil, and no. 5 fuel oil on sand, loam, and clay show that component recovery rates for argon supercritical fluid extraction (SFE) generally increase with increasing pressure and/or temperature. The highest recovery rates (and recoveries) were obtained for Ar SFE at 500 atm and 150 °C. Under these conditions, the components of the gasoline and no. 1 fuel oil spikes could be recovered in as little as 12 min. However, the no. 5 fuel oil components could not be quantitatively removed from the loam and clay matrixes even for extraction times as long as 100 min. We also show in this work that Ar SFE performs similarly to CO2 SFE for petroleum hydrocarbon contamination in real-world soil samples under moderate pressure and temperature conditions. Specifically, Ar SFE and CO2 SFE have similar recoveries and reproducibilities, but Ar SFE requires a slightly longer extraction time.