ABSTRACT
The influencing factors of ultrasonic extraction(UE) and ultrasonic-soxhlet extraction(USE) were analyzed based on orthogonal experimental design. The optimum analytical conditions of two methods were determined. The three different methods: UE, USE and traditional soxhlet extraction(SE) were compared by simultaneous analysis with three different soil samples: fresh contaminated soil, soil after microbial remediation and soil after phytoremediation. The optimum condition of the UE was extracting 4 times with chloroform, 15 mL extractant every time. The optimum condition of the USE method was ultrasonic for 10 min at 60 W, followed by soxhlet extraction with 125 mL extractant for 6 h. Compared the three different methods, USE method showed the best result with the highest average extraction rate of 102.98%, the UE method with average extraction rate of 99.69%, and the SE method with low average extraction rate of 97.31%. The research indicates that USE method is effective in determining soil total petroleum hydrocarbons(TPH) within shorter time and higher efficiency and can be used as a method for determining TPH content in different soils.