| In this paper,the method of spinosad residue analysis for wheat,corn,rung bean and paddy,which were the top four unprocessed grain,was established by high-performance liquid chromatography(HPLC).The spinosad contents in stored grains and the residual effect of spinosad were also studied.The method of spinosad residue analysis in unprocessed grain by HPLC was finally determined after the improvement of the samples for HPLC,the extraction technology and the technical parameters which contained the composition and proportion of mobile phase,mobile phase flow rate,column type and detection wavelength in HPLC.This method was very convenient,after being extracted with methanol by ultrasonic,separated with high speed and filtrated through organic ultrafiltration,the sample could be used in HPLC.The recoveries of the method were 71.2% to 96.8%,the relative standard deviation(RSD)was 1.1% to 13.5%,the recoveries and RSD were within the desired range of residue analysis,and accorded with the requirements of pesticide residue analysis.In this paper,the simulation of the application process with spinosad powder in granary was studied,the residue situation of spinosad in 25±2? after a year was analyzed after the treatment to wheat,corn,rung bean and paddy with 1.0mg/kg 0.5% spinosad which was the recommended dosage.0.5% of spinosad powder in the granary simulation test accorded with the requirements of the first order kinetics,the dynamic curve of its digestion had a half-life of 9.33 to 10.65 months,at the 12 nd month there were 0.38mg/kg to 43mg/kg spinosad left over.Therefore,may infer,that the ADI of Chinese people is just 0.0910 mg to 0.1023 mg per person per day from paddy.Risk quotient(that is accounted for per capita daily intake percentage)is only 7.6%-8.5%,its low dietary exposure,So the residue at safe levels.0.5% spinosad can be used to store grain for food in at least a year with 1.0mg/kg which was the recommended dosage,usually 7 ~ 14 d can be completely degraded in the light of the case after the granary,before serving in the photolysis of water conditions,the half-life is less than 1d.Defferent kinds of grain had defferent influence to spinosad powder residue,the initial dose with 1.0mg / kg in wheat residue most after 12 months study and the spinosad powder residue rate was 42.67%,followed by green beans,corn and paddy,and paddy residual rate was 37.91%,the difference between the highest and lowest values is very small.Compared with light and water,the type of grain was not the main factors of spinosad residues.In this paper,the control persistence of 0.5% spinosad powder was studied.Rhyzopertha dominica was more sensitive to spinosad.It could be totally controlled in 12 months,which indicated that the persistence prevention might reach one year.Sitophilus zeamais was less sensitive to spinosad.However,more than 79% of Sitophilus zeamais was killed by spinosad after 12 months.The efficacy of 0.5% spinosad powder was proportional to its residue.As the storage time extended,the active ingredients of spinosad powder reduced,and the killing effect of Sitophilus zeamais went down.But in long-term effect research,there was no other pests except the access one.we suggested that the 0.5% spinosad powder could be used as stored grain protectant. |
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