Study On The Residual Detection And Degradation Dynamics Of Chlorfluazuron And Triazophos In Rice

This article researched the residue analysis rule of 31% chlorfluazuron and triazophos two kinds of mixtures of pesticides in rice, rice water and soil,In order to give the scientific theory and experimental evidence.The main research contents are shown as follows:1. The residue analytical method of chlorfluazuron by HPLC in rice and soil and was established,at the same time the article studied the analytical method of triazophos by GC. The chlorfluazuron and triazophos in soil and water could be extracted with acetone, afterwards purificated with dichloromethane,and then diluted with methanol to volume .In the end, chlorfluazuron was detected by HPLC and triazophos was detected by GC.In rice and leaf,the pesticides were extracted with acetonitrile,and re-extracted with dichloromethane.The concentrated liquor purificated by the neutral aluminum oxide chromatographic analysis column.At last the concentrated leachates were diluted with methanol to volume,and detected by HPLC and GC. The method of sensitivity, precision, accuracy comply with standards for pesticide residues.2. The residue analysis rule, degradation dynamic and fiinal residue of 31% chlorfluazuron and triazophos in rice and soil were studied through two-year field experiment in Tianjin, Zhejiang and Guangxi province. The rice and soil were treated with the pesticides at 1.5 times of the recommendation dosage.The result shown that the degradation process in line with the mathematic pattern:C=C0e-kt .The half life is less than 30 days, so the chlorfluazuron and triazophos can be degraded easily in rice and soil.3. The rice and soil were treated with the pesticides at recommendation dosage and 1.5 times of the recommendation dosage,as the fiinal residue experiment. Collect the the harvest of rice, water, and soil samples for testing.The result shown that the maximum residue limit of chlorfluazuron and triazophos in rice were 0.0280 mg·kg-1 and 0.0375 mg·kg-1 in 35 days after the last sprayed pesticides.It has been lower than the maximum residue limit.4. At present, the maximum residue limits(MRL) of chlorfluazuron in rice is 0.05 mg·kg-1 in China. The maximum residue limits(MRL) of triazophos in rice is 0.05 mg·kg-1, the one in wheat, corn grain and sorghum is 0.01 mg·kg-1 in China. Refered to the standards for maximum residue limits, two doses of 31% chlorfluazuron and triazophos were sprayed in rice for two times at recommended dosage and two times of the recommendation dosage.The result has shown that it is safe of the residue of chlorfluazuron and triazophos in rice and soil in 35 days after spraying 1.5 times of the recommendation dosage at the safely interval of 35 days.