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A rapid multiresidue method has been developed for the analysis of 17 organochlorine pesticides (OCPs) (α-HCH, γ-HCH, β-HCH, δ-HCH, aldrin, heptachlor epoxide, endosulfan I, 4,4-DDE, dieldrin, endrin, 4,4-DDD, endosulfan II, 4,4-DDT, endrin aldehyde, endosulfan sulfate, methoxychlor and endrin ketone) in marine sediments. The method is based on the ultrasonic solvent extraction (USE) of sediment samples. The extraction procedure was optimised with regard to the solvent type, amount of solvent and duration of sonication steps. Analytical determinations of the 17 OCPs were carried out by gas chromatography using electron capture detector (GC/ECD). The highest recoveries from sediment samples spiked at trace concentrations of 50 ng g–1 obtained when samples were extracted two times by ultrasonication for 20 min with 5 mL of dichloromethane. Recovery studies were performed at 1, 2, 5, 10 and 50 ng g–1 fortification levels and correlation coefficients obtained ranged from 0.9652 to 0.9993 showing that the method is linear over the range assayed. The detection limits (signal/noise = 3) for the organochlorine compounds tested in marine sediments varied from 0.1 to 1 ng g–1 dry weight. USE of OCPs from marine sediments using dichloromethane showed satisfactory extraction efficiencies combined with simplicity of use and low solvent consumption.

This paper demonstrates that ultrasonic solvent extraction is an efficient, cost effective and Table 5 Regression lines, correlation coefficients and limit of detection of OCPs studied Compound Regression line (y = ax + b) Correlation coefficient Limit of detection (ng g–1) α-HCH γ-HCH β-HCH δ-HCH Aldrin Heptachlor epoxide Endosulfan I 4,4-DDE Dieldrin Endrin 4.4-DDD Endosulfan II 4,4-DDT Endrin aldehyde Endosulfan sulfate Methoxychlor Endrin ketone y = 4524.8x + 3420.2 y = 4285.5x + 2749.7 y = 2643.2x + 2692.0 y = 2824.5x + 2749.7 y = 4031.8x + 2256.0 y = 3695.2x + 6807.3 y = 3414.1x + 3920.6 y = 3443.6x + 2095.2 y = 3196.1x + 3014.7 y = 2875.4x + 2391.9 y = 2265.6x + 2601.2 y = 1481.3x + 2058.1 y = 2610.6x + 2945.5 y = 1709.3x + 678.6 y = 2313.3x + 2379.8 y = 894.76x + 800.0 y = 2876.2x + 5509.1 0.9909 0.9941 0.9935 0.9951 0.9949 0.9652 0.9938 0.9782 0.9887 0.9870 0.9818 0.9903 0.9993 0.9910 0.9920 0.9975 0.9914 0.2 0.2 0.2 0.3 0.1 0.1 0.1 0.3 0.2 0.1 0.1 0.5 0.1 0.5 0.4 1.0 0.1 environmental friendly procedure for extracting organochlorine pesticide residues from marine sediments. The proposed method is a rapid and sensitive method based on sonication-assisted extraction of sediment samples using dichloromethane as extracting solvent. This technique provides good response linearity, high precision and low detection limits. The major advantage of the optimised USE procedure is the much lower extraction time and the elimination of an additional clean-up stage involving additional glassware and apparatus.