| In order to provide basic data for residual rule of 40%Carbendazim·Bromothalonil·Thiram, analysis methods of 40%Carbendazim·Bromothalonil·Thiram residue and degradation in cucumber and soil, and its final residues were studied. The results were shown as follows:1.Residue analysis method of bromothalonil was established in cucumber and soil. The bromothalonil could be extracted with acetone, and then re-extracted with dichloromethane. After being concentrated by evaporation, the residue was reconstituded with acetone and detected in GC(NPD) and GC-MS. The limit of detection in GC(NPD) was 1×10-11 g, and limits of quantitation of bromothalonil in cucumber and soil were both 0.1 mg/Kg. In the three levels of 0.1 mg/Kg, 0.5 mg/Kg and 1 mg/Kg, the average recoveries in cucumber and soil were 82.57%～87.69% and 91.25%～93.09%, respectively, and the relative standard deviations were 25.37%～6.04% and 2.40%～4.32%, respectively. The minimum detectable limit of the GC-MS was 1×10-11 g, and the minumun detectable concentration of Bromothalonil in cucumber and soil was all 0.1mg/Kg. In the three level of 0.1 mg/Kg, 0.5 mg/Kg and 1 mg/Kg, the average recoveries in cucumber and soil were 91.54%～108.93% and 99.03%～110.87%, with the relative standard deviations were 4.57%～5.85% and 4.02%～8.68%, respectively. The sensitivity, accuracy and precision of the method well satisfied the essential rules of pesticide residue determination.2. Residue analysis method of carbendazim was established in cucumber and soil. The sample was extracted with ethyl acetate and determined by UPLC-MS/MS. The precursor ion/product ion transitions were m/z 191.2/130 and m/z 191.2/160 at the mode of multi-reaction monitor and m/z 191.2/160 was used for quantification. The limit of detection in UPLC-MS was 3×10-12 g, and limits of quantitation of carbendazim in cucumber and soil were both 0.01 mg/Kg. In the three levels of 0.01 mg/Kg, 0.05 mg/Kg and 0.1 mg/Kg, the average recoveries in cucumber and soil were 96.75%～101.87% and 98.15%～109.48%, with the relative standard deviations were 2.77%～3.31% and 2.99%～5.64%, respectively. The sensitivity, accuracy and precision of the two methods well satisfied the essential rules of pesticide residue determination, but the sensitivity of UPLC-MS determination was better. The limit of detection in HPLC was 2×10-10 g, and limits of quantitation of carbendazim in cucumber and soil were both 0.1 mg/Kg. In the three levels of 0.1 mg/Kg, 0.5 mg/Kg and 1 mg/Kg, the average recoveries in cucumber and soil were 86.09%～91.79% and 95.30%～97.10%, with the relative standard deviations were 2.50%～3.58% and 2.13%～3.27%, respectively.3. Degradation dynamic of 40%Carbendazim·Bromothalonil·Thiram in cucumbers and soil was studied by a one-year four fields (2008) experiments in Shandong, Zhejiang, Henan and Beijing. The cucumbers and soil were treated with the pesticides at recommended dosage and two times of the recommendation dosage. Samples of cucumber and soil were analysised at different time, then the degradation procedure was corresponding to the mathematic pattern: C=C0e-kt. The half lifes of carbendazim in soil were 4.9～6.9 d, and that in cucumber were 2.0～2.8 d. The half lifes of bromothalonil in cucumber were 1.1～1.5 d. The result showed that carbendazim and bromothalonil were degraded easily in cucumber and soil.4. With sprayed 40%Carbendazim·Bromothalonil·Thiram on cucumbers and soil at recommended dosage by a one-year four fields (2008) experiment in Shandong, Zhejiang, Henan and Beijing, on the 5th day after the last application, the final residue of Carbendazim and Bromothalonil in cucumber was≤0.366 mg/Kg and <0.2 mg/Kg.
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