Determination of Total Petroleum Hydrocarbons in Low Oil Contaminated Soil by Infrared Spectrophotometry with Accelerated Solvent Extraction

The extraction of total petroleum hydrocarbons from low oil contaminated soil by acceterated solvent extraction (ASE) was studied and compared with Soxhlet extraction, ultrasonic extraction and microwave extraction. The simulated pollution samples were prepared, and the ASE conditions were optimized by single factor and orthogonal experiments, and the petroleum hydrocarbons were determined by infrared spectrophotometry. The results showed that the optimal ASE conditions of total petroleum hydrocarbons in low oil contaminated soil were:pressure of 1.03×10⁷Pa, extraction time of 15 min, extraction temperature of 100℃, circulating extraction for 4 times, nitrogen blowing for 45 s, extraction agent of acetone-dichloromethane (1+1) mixed solvent. The total petroleum hydrocarbons in soil under different irrigation years were determined by the above method. The range of mass fraction of petroleum hydrocarbons in soil in a sewage irrigation area of Xinjiang was 211.05-389.50 mg·kg^-1, with RSDs (n=5) in the range of 2.3%-6.4%.