Studies On Residue Dynamics Of Diniconazol In Pears And Soil

Residue analytical methods of diniconazol in pears and soil were established. Dissipation dynamics and the terminal residue of diniconazol in pears and soil and photochemical degradation of diniconazole in soil had been studied in this paper.Residues of diniconazole were extracted from pear and soil with acetone,acetonitrile, respectively,cleaned up by column chromatography of silica gel,and determined by GC The average recoveries and coefficient of variations of the method were 86.13%-98.12%, 1.36%-6.88%for pear samples,and 88.53%-101.11%,2.11%-3.72%for soil sample, respectively.The limit of detection(LOD) of diniconazole was 2×10^-11g and the method detection limit(MDL)of diniconazole in the samples of pear and soil were 0.01 mg/kg. These results showed that the method accords with demands of residue analysis of pesticide.With the mentioned method,dissipation dynamics and the terminal residue of diniconazol were determined in pears and soil in Anhui,Shanxi,Shandong and Tianjin. The result showed that the dissipation rate of diniconazol in pear and soil was slowly degraded.The dissipation halflife of diniconazol in pear in Anhui was 6.67 d.It in Shanxi was 6.37 d.It in Shandong was 6.78 d.It in Tianjin was 7.74 d.The dissipation halflife of diniconazol in soil in Anhui was 9.97d.It in Shanxi was 7.97d.It in Shandong was 9.05d. It in Tianjin was 13.28d.When recommended dose was used,at harvest,the terminal residue of diniconazol in pears and soil in Anhui was 0.017 mg/kg,0.069 mg/kg,It in Shanxi was 0.025 mg/kg,0.024 mg/kg,It in Shandong was 0.020 mg/kg,0.045 mg/kg,It was in Tianjin 0.022 mg/kg,0.065 mg/kg,respectively.The result suggest that the recommended dose is safe to use,less than three time and last time should be earlier 28d than harvest.Photochemical degradation of diniconazol in soil followed a first order reaction.The photolysis half-life of diniconazol in soil of soil moisture20%,soil moisture40%,soil moisture60%was 43.87h,48.47h,52.91h respectively.The photolysis half-life of diniconazol in soi of initial concentrations 1.0mg/kg,initial concentrations 5.0mg/kg, initial concentrations 10.0mg/kg was 36.67h,48.47h,63.01h respectively.