Dissipation Rates and Final Residues of Kresoxim-Methyl in Strawberry and Soil

In order to study the dissipation rates and final residues of kresoxim-methyl in strawberry and soil, two independent filed trials were performed in Beijing China. The application rates are set at 195 g of active gradient per hectare. A simple analytical method has been developed for the determination of kresoxim-methyl in strawberry and soil. Kresoxim-methyl residues were extracted with acetonitrile from strawberry and soil samples which is determined by gas chromatography coupled with mass spectrometry detection (GC–MSD). The recoveries of kresoxim-methyl in strawberry and soil were observed from 78.9 % to 104.5 % at fortification levels of 0.01–0.5 mg/kg with relative standard deviations of 4.3 %–7.3 %. The reported limits of detection were 0.05 and 0.01 mg/kg for strawberry and soil, respectively. The results showed that kresoxim-methyl dissipation in strawberry could be described as first-order equation with the half-life time of 6.24 and 6.91 days. 14 days later, the dissipation rate is 84.9 % and 83.3 %, respectively. The final residues of kresoxim-methly in the strawberry were in the range of 2.7–4.8 mg/kg at pre-harvest intervals of 1, 3, 5, 7 days which is below the Japan maximum residue limits (MRLs) standards (5 mg/kg in strawberry).