Residue Analysis And Digestion Dynamics Of Pyraclostrobin On Grape By 45% Pyraclostrobin Enoylmorpholine Suspension

Pyraclostrobin is new type of methoxyacrylate fungicide in China;mainly used for prevention of vegetables;fruits and other economic crops from fungal diseases.In this paper,an ultra performance liquid chromatography(UPLC-PDA)method was developed to determine the residues of pyraclostrobin in grapes.The grape and soil samples were extracted with acetonitrile;then the grape samples were cleaned up by N-propyl ethylenediamine(PSA)and C18;all samples were concentrated and analyzed by ultra-high performance liquid chromatography(UPLC-PDA).The results showed that the spiked levels of pyraclostrobin were from 0.05 to 5.00 mg/kg in grape and soil samples.The recoveries were ranged from 81.95% to 91.51% with RSDs between 2.60% and 5.67%.The results of the addition of pyraclostrobin in blank grapes and soil were in accordance with the requirements of the Chinese pesticide residue test(NY/T 788-2004).The external standard curve expressed a good linearity between 0.1 and 50.0 ?g/mL with the correlation coefficient of 0.9997.The limit of detection was 3.0×10-10 g.The limit of quantification was 0.05 mg/kg.The field trails were conducted at Guizhou and Anhui province during the agricultural season in 2015 and 2016 to study the dynamic dissipation and terminal residue of pyraclostrobin.A scientific basis for the safely use and residue determination of pyraclostrobin in grape was carried out.The residues of pyraclostrobin in grape and soil samples were carried out.When the dosage of the compound was 1200-800 times,the application time was 3-4 times,the interval of spraying was 5 days,the interval of harvest was 7,14,21 d,the final residual amount of pyraclostrobin in the harvest grape was <0.05-0.71 mg/kg;lower than 2.00 mg/kg the maximum residue limit(MRL)of pyraclostrobin residue on the grape in China(GB2763-2014).Therefore,45% pyraclostrobin·dimethomorph SC can be applied safely on grape with the recommended dosage and time.In this paper,the indoor simulation experiments were designed for exploring the environmental factors for the degradation of pyraclostrobin and dimethomorph in different water.A method of determining pyraclostrobin and dimethomorph in different water environmental was developed by an ultra-performance liquid chromatography-photodiode array detection(UPLC).And the degradation of the pyraclostrobin and dimethomorph under different water environmental factors was obtained,which provided reference for understanding its degradation in water environment.