Investigation Of Detection Approach Of SPE-HPLC Of Avermyctins

In this research, a novel chromatographic analysis method is established to analyze pesticide residua by combining solid-phase extraction technology(SPE)with high performance liquid chromatography(HPLC),aiming to overcome the defect in general method in pesticide residue analysis such as: solvent toxicity, bio-hazard, which is proved to meet the basic demand of pesticide residua analysis and possesses high recovery rate, less-time cost, good repeatability and feasibility. Meanwhile ,study on dynamically controlling rudimental of avermyctins in field soil and broccoli is performed by using SPE-HPLC method, the results obtained indicates that this method is practical and effective for instructing the field application of avermyctins .In this thesis, positive SPE column, filling with Florisil, is firstly prepared, The chromatographic performance of the pre-treated soil sample and broccoli is studied in detail by SPE-HPLC method and compared with that of the commercial SPE sample. The average recovery rate and the variation coefficient is 89.24%,89.94% and 2.73% 1.82% respectively, It is indicated that column-efficiency is approximately equal, however, the homemade SPE-column is more superior on economy. Avermyctins derivative is synthesized from trifluoroacetic anhydride and N-methylimida zole. Spectroscopic analysis is applied to determine avermyctins derivative to expel the interfere of the impurity in the soil sample and the broccoli, the detectable limit reaches 0.001mg/kg, the linearity range of avermyctins stand curve is from 10ng/mL to 200 ng/mL and the correlate coefficient is 0.999. The feasibility of the SPE-HPLC method is validated by standard appending 0.005mg/kg, 0.05mg/kg and 0.1 mg/kg respectively, in this way, when the concentration is 0.005mg/kg, the recovery rate is between 81.12% and 103.28%, correlation coefficient is between 6.33% and 7.61%; when the concentration is 0.05mg/kg, the recovery is between 84.56% and 100.37%, correlation coefficient is 2.46% to 4.65%; and when the concentration is 0.1mg/kg, the recovery is 87.98% to 104.14%, correlation coefficient is 2.90% to 4.33%, all the test data are meet the rudimental pesticide analytical demand. Based on those experiment results, the SPE-HPLC method is set up to dynamically analyze rudimental avermyctins in soil and broccoli. The result showed that the digest dynamic equation and half-life of avermyctins in broccoli are Ct=1006.30e^-0.24X,2.8h , Ct=461.64e^-0.24X,2.9h , respectively under the condition of avermyctins is 13.5g/hm2 and 27g/hm² in broccoli.