| Azoxystrobin is one of strobilurin fungicides, pesticides that contain azoxystrobin are recommended for protection of fruits and vegetables, It can be also used to protect more than 80 kinds of crops against fungal diseases such as rice, grape, potato, It has a wide range of applications. A rapid and sensitive method has been developed for the determination of azoxystrobin in soybean.The samples were extracted with acetonitrile, cleaned up by glass column chromatography with Florisil, eluted with mixture of acetone:n-hexane (v:v,8:2), the residual dynamics and final residues of azoxystrobin were detected by gas chromatography withμ-ECD. The minimum amount of detection was 1×10-12g, and the minimum concentration of detection in soil, plant and soybean were 2×10-4mg·kg-1 and 1×10-3 mg·kg-1, respectively. The different addition level of soil, plant and soybean were 0.025mg·kg-1, 0.25mg·kg-1,2mg·kg-1, and average recovery of azoxystrobin were 94.0～104.5%,93.4～101.1%,88.4～93.8%, respectively. The coefficients of variation ranged from 1.6～7.1%,2.1～7.5%,1.2～7.2%, respectively.Residual trial of azoxystrobin were conducted in Jilin, Shandong and Heilongjiang during 2008～2009. Two years field trial showed that the half-life of azoxystrobin was 1.0-4.9d in soil and 0.8-3.6d in plant. The degradation procedure of azoxystrobin was accordance with the first-order kinetic equation C=C0e-kt. In soil, the dynamic equation in 2008 was C=0.4825e-0.0825t (Jilin), C=0.8920e-0.0484t (Shandong) and C=0.4503e-0.0485t (Heilongjiang); The dynamic equation in 2009 was C=0.5919e-0.0841t(Jilin), C=0.4681e-0.0428t(Shandong) and C=0.5623e-0.0845t (Heilongjiang). In plant, the dynamic equation in 2008 was C=50.205e-0.2414t (Jilin), C=36.217e-0.2335t (Shandong) and C=38.572e-0.2064t (Heilongjiang); the dynamic equation in 2009 was C=12.354e-0.1742t (Jilin), C=104.84e-0.2750t (Shandong) and C=44.958e-0.2401t (Heilongjiang). The degradation rate was more than 90% in plant after 14 days, and the degradation rate was almost more than 80% in soil after 30 days. And the results showed that azoxystrobin was easy to degrade in plant and soil (T1/2<30d).Soybean plant were treated three and four times with the dosages of 225 a.i.g·hm-2 and 337.5a.i.g·hm-2. The final residue of azoxystrobin in soil plant and soybean were detected, but the zaoxystrobin residue in soybean were all below 0.3mg·kg-1.According to the result of test, recommended dosage 225 a.i.g·hm-2 of 25% azoxystrobin SC was suggested to apply in the soybean field. The MRL of azoxystrobin in soybean in our country may be suggested to be 0.5 mg·kg-1. It is recommended that the pre-harvest interval of azoxystrobin in soybean were set at 14 days, the maximum application times is suggested blow three.In this study azoxystrbin molecularly imprinted polymer (MIP) was prepared using azoxystrobin as template molecule, MAA as functional monomer, EDMA as cross-link, acetonitrile as porogen. The results showed that the ratio of azoxystrobin, MAA and EDMA was 1:4:20. And by using bulk polymerization and precipitation polymerization prepared MIPs, explored the advantages and disadvantages of two ways. The MIP was get into solid phase extraction column, application of MISPE in pre-treatment of azoxystrobin, a high degree of cleaning up and acceptable recoveries were obtained, measured up to residue analysis. |
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