Determination of heavy hydrocarbon contamination using supercritical fluid extraction with infrared detection

✍ Scribed by Steven B. Hawthorne; Kristen M. Hegvik; Yu Yang; David J. Miller

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 540 KB
• Volume: 73
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(94)90215-1

✦ Synopsis

Supercritical fluid extraction (s.f.e.) conditions to extract heavy hydrocarbons quantitatively from soil were developed, using high temperature (150°C) and an infrared-clear organic solvent. S.f.e. with pure CO, at 65'C gave good recovery of light crude oil components (SC25 alkanes) but did not efficiently extract heavier components.

An increase in temperature during s.f.e. to 150°C increased the recovery of the heavier hydrocarbons, but the best recoveries were achieved by extraction at 150°C after addition of perchloroethylene as a modifier. Under these conditions, s.f.e. (15 min static followed by 15 min dynamic extraction) gave recoveries 545% higher than did 4 h of Soxhlet extraction for soils contaminated with light to heavy crude oils, motor oil and heavy residual oil. Adsorption of the extracted polar compounds on silica indicated that both polar and non-polar organics were more efficiently extracted by s.f.e.. Since the modifier is added directly to the soil sample, the method does not require either dual pumps or premixed fluids.