A rapid, sensitive, and reliable HPLC method has been developed for the determination of imidacloprid residue in nine kinds of crops and soil. The developed method consisted of extracting with acetonitrile/water (80:20 v/v), prewashing of the concentrated extracts with cyclohexane and alkaline solution, silica gel column chromatography, and finally reversed-phase HPLC. The recoveries of imidacloprid were 75-109%. The limits of determination of the method were 0.005, 0.01, and 0.02 mg/g for crops, rice straw, and soil, respectively. The method was applied to determine residues and rate of disappearance of imidacloprid from rice (nursery box treatment, 1 g of ai/1800 cm 2 ) and cucumber plants (stem injection, 20 μg of ai/plant)
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