The Studies On Residue Of Malathion And Fenitrothion In Stored Grain

The pesticides of two kinds of organophosphorus, malathion and fenitrothion, which are main pesticides used during the crop growing in the field and grain storage period, were investigated in the paper. The determination method of malathion pesticide on stored grain was established, and the dynamic degradation process of malathion and fenitrothion on stored grain was also studied. The main research content and the results could be summerized as follows:1. The capillary column gas chromatography method was established for testing organophosphorus pesticides on stored grain. The average recovery rate was 92.08% ~ 97.25%, coefficient of variation was 0.944% ~ 3.432%, which satisfied the requirement of pesticides determination.2. The dynamic degradation process of malathion on stored grain was studied by the established capillary column gas chromatography method at different concentrations, temperatures and relative humidities: three kinds of concentrations (10 mg/kg, 20 mg/kg, 30 mg/kg) and three kinds of temperature and relative humidity combination combination: (1) high temperature and relative humidity area (25℃, relative humidity 75%); (2) The cold-wet zone, the temperature 10℃, relative humidity 60%; (3) natural condition (Beijing area). The different concentrations of malathion was applied on stored paddy rice, wheat and corn. The results showed that different concentrations of malathion on stored grain degraded at a faster rate under high temperature and relative humidity area. The rate of degradation at the three kinds of temperature and relative humidity combination combination was listed in descending order as follows: high temperature and relative humidity area >cold-wet>natural condition zone. In the same temperature and relative humidity conditions, the degradation rate of different concentrations of malathion on stored grain was listed in descending order as follows: 30 mg/kg >20 mg/kg >10 mg/kg.3. Study on the dynamic degradation law of fenitrothion on three main grains. To definitize the degradation situation of residual fenitrothion on stored grains, evaluate the environment security then provide direction on scientific and rational logical use and ensure agricultural products safety supply, we adopt gas chromatography during the study. Fenitrothion residue analysis methods was established by recovery. With the gas chromatography technology, we tested the rescue dynamic of fenitrothion on grains which was ever operated in laboratory. Research indicates: grain species affect fenitrothion degradation and degradation rate on wheat, corn and rice from high to low is: rice>corn>wheat.