Determination of 21 Phenolic Compounds in Oilfield Soil by Ultrasonic Extraction-Gas Chromatography

21 phenolic compounds in oilfield soil were determined by ultrasonic extraction-gas chromatography. The effects of extraction time and purification conditions on extraction efficiency were studied. The effects of pressurized fluid extraction and ultrasonic extraction on recovery were compared. The results showed that the recovery rate of ultrasonic extraction was better than that of the pressurized fluid extraction, in which 2, 4-dinitrophenol and 4-nitrophenol were used. The recovery rate of the pressurized fluid extraction method was increased by 30%, the detection limit of the phenolic compound was 0.01~0.05 mg/kg based on 10.0 g of the soil sample, and the sample recovery rate was 81.5% to 110%, and the precision was 2.6%~11%; the relative error was 2.6%~14% verified by certified reference materials. Ultrasonic extraction method is suitable for the determination of 21 phenolic compounds in oilfield soil.