Study Of Spinosad And Its Metabolites' Residues In Cotton Soil,Cotton Leaf And Cottonseed

In This article, cleanup methods and chromatograpHic analysis method for spinosad residue analysis was opitimised and a reliable residue analysis methods was developed.In the experiment , reversed C18 column was employed . the moble phase contain methanol , acetonirole and acetated alumium with ratio of 32,64 and 5 was used.The effect of pH value drying agent and different type of SPE column in the clean-up step I was compared . According to previous parameter , A selective and sensitive method utilizing liquid chromatograph (HPLC) was developed for determining residues of spinosad in several matrices.For cottonseed, the method had a limit of quantitation (LOQ) of 0.003mg/kg. For soil, the method had an LOQ of 0.003mg/kg .For cottonseed,the average recoveries ranged from 76.1%-91.4% with standard deviations ranging from 2.35 to 11.34%. For soil,the average recoveries ranged from 77.2%~ 93.5% with standard deviations ranging from 2.97 to 7.56%. For cotton leaf, the average recoveries ranged from 77.0%~93.3% with standard deviations ranging from 3.21 to 7.26%.Spinosad and it's several minor metabolites was also measured by LC/MS method . The method have limits of quantitation of 0.005mg/kg in soil. Due to LC/MS method have excellent performance in the eliminating interfere ,The clean-up presedure was simplified in this article .In the field trial , no Spinosad residue was determined in the cottonseed when the spray concentration from 80ml/mu to 160ml/mu using 2.5% Spinosad SC in the field. Beside spinosyn B have a concentration of 0.02mg/kg in the soil ,There is no other compounds han been deterimined in the soil. Results also demonstrated that spinosad residues in the cotton leaf and cotton soil dissipated rapidly, spinosyn A had half life of 3.01 in the cotton leaf, 2.18 in the cotton soil, spinosyn D had half life of 1.96 in the cotton leaf, 2.29 in the cotton soil. The half life of Spinosad total residue which including spinosyn B and Spinosyn DMSD was 3.61 in the cotton leaf, 2.54 in the cotton soil. Spinosad and it's several minor metabolites residue was not determined after 12 day. It would not be accumulated in the soil and plant.