[Analytical method of hydramethylnon in agricultural products by LC-MS/MS]

A simple determination method of hydramethylnon in agricultural products by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. The sample was homogenized with phosphoric acid and extracted with acetone. An aliquot of crude extract was re-extracted with hexane and sat. NaCl solution. In the case of tea leaf, solidification processing using ammonium chloride and phosphoric acid was performed before re-extraction with hexane. Clean-up was performed using a silica-gel mini column (500 mg). The LC separation was performed on a C18 column using methanol-water (8 : 2) containing 10 mM ammonium acetate as the mobile phase and MS detection with positive ion electrospray ionization. The calibration curve was linear between 0.002-0.2 µg/mL of hydramethylnon. Recoveries (n=5) of hydromethylnon from 10 kinds of agricultural products fortified at 0.01 µg/g (0.05 µg/g for pineapple) were 82-110%, and their relative standard deviations were 2-12%.