Study On Residual Detection And Degradation Rule Of Avermectin And Emamectin Benzoate In Water Bamboo

In this paper, analytical methods of residues for Avermectin and Emamectin benzoate in Water bamboo and its leaves were established. Final residue and dynamic degradation of both insecticides in Water bamboo were studied in this paper. These studies provided the basis for the safe use of the two kinds of insecticides in Water bamboo field. And these main results were as follows:1. Analytical methods of residues for Avermectin and Emamectin benzoate in Water bamboo and its leaves were established. All samples were extracted with acetonitrile and the extracts were cleaned up by NH2 Solid Phase Extraction column, followed by determination using LC-MS/MS. Results showed that: In the range of 0.1 to 1.5 μg/kg, Avermectin’s concentration was in a good liner with peak area value(R2=0.9906). The fortified recoveries tests of Avermectin in Water bamboo plants and Water bamboo were 89.2~99.2% and 90.4~96.3%. The relative standard deviations(RSD) of recovery were2.9~6.9% and 3.4~6.3%. The minimum detectable concentrations was 0.1×10-3mg/kg.In the range of0.01 μg/kg to 1.00 μg /kg, Emamectin benzoate’s concentration was in a good liner with peak area value(R2=0.9950). The fortified recoveries of Emamectin benzoate in Water bamboo plants and Water bamboo were 93.3~96.7% and 86.2~97.3%. The relative standard deviations(RSD) of recovery were5.8~9.5% and 5.6~7.7%. The minimum detectable concentrations was 0.01×10-3mg /kg. The precision and detection sensitivity of these methods all agree with the permitting range. These results showed that the methods agree with demands of residue analysis of pesticide.2. Dynamic degradation of Avermectin and Emamectin benzoate in Water bamboo were studied in this paper. The half lives of Avermectin in Water bamboo were less than 1 day and the half lives of Emamectin benzoate were 0.59 day to 3.34 days. These two pesticides were both easily degraded in Water bamboo(T1/2<30d).3. The final residue test results showed that: 1.8% Avermectin EC was not detected in Water bamboo when 14, 21, 28 d after application with concentration of 18 mg/L and 27 mg/L. And the Avermectin was applied 2 or 3 times every 10 d. 2.3% Emamectin benzoate Micro-Emulsion was not detected in Water bamboo when 14, 21, 28 d after application with concentration of 23 mg/kg and 34.5mg/kg. And the Emamectin benzoate was applied 2 or 3 times at intervals 10 d as well..4. On the basis of experimental results, 1.8% Avermectin EC should be applied 2 times in concentration of 18 mg/L, and the safety interval should be 14 d after the application. 2.3% Emamectin benzoate Micro-Emulsion should be applied 2 times in concentration of 23 mg/kg, and the safety interval should be 14 d after the application.