Residue Analysis Of Metconazole In Grapes And Soil And Study On Its Digestion Dynamics

Metconazole is a novel triazole fungicide developed by Kureha Corporation.It is mainly used for the prevention and control the diseases such as powdery mildew,white rot,anthrax,and gray mold in grapes.In this paper,a method for the determination of metconazole residues in grapes and soil was established.In 2016 and 2017,the field experiment of 8%metconazole suspension in grapes were conducted in Anhui and Guizhou province.The dissipation dynamics,terminal residues and chronic and acute dietary intake of risk assessment of metconazole on grapes and soil were studied,which provided the scientific basis for the security using 8%metconazole suspension.Simultaneously,the degradation of meteconazole in the soil was simulated in laboratory.The effects of different environmental factors on the degradation of metconazole were investigated in order to provide a theoretical basis for studying the effects of metconazole on the environment.The experimental study results are as follows:1.This paper established an improved QuEChERS-GC-MS/MS analysis method to detect the residue of metconazole in grapes and soil.The results showed that a good linearity of metconazole in the range of 0.01-2.00 mg/L,the correlation coefficient(R~2)was greater than 0.999,the limit of detection(LOD)of grape and soil were 0.0006mg/kg,and the limit of quantification(LOQ)was both 0.002 mg/kg.The spiked levels of metconazole were 0.002,0.02 and 0.2 mg/kg in both grape and soil,the recoveries of grape were ranged 79.27 to 93.62%with RSD between 1.56 and 2.27%,and the recoveries of soil were ranged 75.91 to 104.49%with RSD between 2.58 and 6.16%.2.The dissipation dynamics of metconazole in grape and soil in Guizhou and Anhui conform to the first-order kinetic equation.The half-lives of metconazole on grapes and soil were 11.75-21.66 d and 20.39 d,respectively.Terminal residues of metconazole in grapes from Guizhou and Anhui were<0.002-0.190 mg/kg,and the soil were<0.002-0.060 mg/kg.Residues of metconazole from the grape samples collected21 days after the last application were all less than 0.02 mg/kg(lower than the MRL value of metconazole in grapes set by the EU:0.02 mg/kg).3.The chronic and acute dietary intake risk of metconazole in grapes showed that the RQc and RQa of male and female at all ages was far less than 1,spraying it with recommended dose.on grapes are no health risks for human consumption.4.The effects of different environmental factors on the degradation of meteconazole in soil were simulated indoors.The results showed that the degradation of meteconazole in soil was affected by many environmental factors such as temperature,moisture content,organic matter,microorganisms,and pH,etc.The cultivation temperature is ranged 15 to 35oC,and the moisture content is in the range of 12%-36%,the faster the meconazole degradation,when the temperature,the moisture content,microorganisms and organic matter content is higher.