Study On Residue Dynamics Of Cinosulfuron·Acetochlor Wettable Powder In Rice

Residue analytical methods of Cinosulfuron and Acetochlor in soil,rice plant,water and rice were established. Dissipation residue of Cinosulfuron and Acetochlor in soil,rice plant,waterand rice, had been studied in this paper.Residues of Cinosulfuron were extracted from rice plant ,rice and soil with methanol,cleaned up by SPE cartridge,and determined by HPLC equipped with UV detector.The average recoveries and coefficients of variation of the method were 98.09%～105.96%,3.99%～4.36% for rice plant samples;87.76%～98.75%,2.88%～6.75% for rice samples; 87.85%～100.53%,2.45%～7.26% for soil samples; 86.19%～107.90%,3.31%～8.59% for water samples,respectively.The limit of detection of of Cinosulfuron (LOD)was 2ng,and the minimum detectable concentrations was 0.04mg/kg,0.02 mg/kg and 0.04mg/L,respectively.The results showed that the method accords with demands of pesticide residue analysis.Residues of Acetochlor were extracted from soil and rice plant with methanol, while residues of Acetochlor were extracted from rice with acetone, cleaned with Florsil Soil and determined by GC-ECD. The average recoveries and coefficient of variations of the method were 91.78～103.71%,2.29～4.27% for rice plant samples; 84.58～90.47%,3.78～4.84% for rice samples; 82.96～88.32%,4.94～8.69% for soil samples; 91.28～100.56%,1.07～5.89% for water samples,respectively. The limit of detection of Acetochlor (LOD) was 0.02ng . and the minimum detectable concentrations was 0.01mg/kg,and 0.01mg/L,respectively.These results showed that the method accords with demands of residue analysis of pesticide.With the mentioned method, residual dynamics of Cinosulfuron and Acetochlor had been determined in soil,rice plant and water in Anhui ,Tianjin,Hunan and Hainan during 2007 .The result showed that the degradation half-life of Cinosulfuron in Tianjin in soil ,rice plant and water was 4.06 d ,2.75d and 1.54d; in Anhui ,the degradation half-life of Cinosulfuron in soil,rice plant and water was 2.64d,1.04d,1.80d; the degradation half-life of Cinosulfuron in Hunan in soil,rice plant and water was 3.77d,2.29d,1.55d; the degradation half-life in Hainan in soil,rice plant and water was 1.96d,2.39d,2.33d; the degradation half-life of Acetochlor in Tianjin in soil,rice plant,water was 9.17d,5.76d,9.06d; the degradation half-life in Anhui in soil,rice plant,water was 8.51d,5.31d,2.91d; the degradation half-life in Hunan in soil,rice plant and water was 5.61d,4.06d,4.13d; the degradation half-life in Hainan in soil,rice plant and water was 5.60d,8.47d,5.19d.