Optimization of Ultrasonic Extraction and Clean-up Protocol for the Determination of Polycyclic Aromatic Hydrocarbons in Marine Sediments by High-performance Liquid Chromatography Coupled with Fluorescence Detection

P732; The procedures of ultrasonic extraction and clean-up were optimized for the determination of polycyclic aromatic hydrocarbons(PAHs)in marine sediments.Samples were ultrasonically extracted,and the extracts were purified with a miniaturized silica gel chromatographic column and analyzed with high performance liquid chromatography(HPLC)with a fluorescence detector.Ultrasonication with methanol-dichloromethane(2:1,v/v)mixture gave higher extraction efficiency than that with dichloromethane.Among the three elution solvents used in clean-up step,dichloromethane-hexane(2:3,v/v)mixture was the most satisfactory.Under the optimized conditions,the recoveries in the range of 54.82％ to 94.70％ with RSDs of 3.02％ to 23.22％ for a spiked blank,and in the range of 61.20％ to 127.08％ with RSDs of 7.61％ to 26.93％ for a spiked matrix,were obtained for the 15 PAHs studied,while the recoveries for a NIST standard reference SRM 1941b were in the range of 50.79％ to 83.78％ with RSDs of 5.24％ to 21.38％.The detection limits were between 0.75ngL-1 and 10.99ngL-1for different PAHs.A sample from the Jiaozhou Bay area was examined to test the established methods.