Residue Analysis And Digestion Dynamics Of Pesticides Nitenpyram And Chlorfenapyr In Lonicera Japonica Thunb.

Lonicera japonica Thunb.is a common bulk medicinal material.It is widely used in China and even in the world.Because it is vulnerable to pests and diseases,pesticides are inevitably used in the planting process.However,there is no registration for the safe use of pesticides in Lonicera japonica Thunb.in China,and the unreasonable use of pesticides is serious,resulting in serious pesticide residues in Lonicera japonica Thunb.It seriously affects the quality of honeysuckle products and affects the import and export trade of honeysuckle in China.Therefore,it is extremely urgent to study the residue analysis and dynamics of pesticide residues in Lonicera japonica Thunb.In this study,two new pesticides,nitenpyram and chlorfenapyr,were selected,and the determination method was established to study the residue law,so as to propose the safe use of Lonicera japonica Thunb.pesticides.The results are as follows:1.A method for determining the residues of nitenpyram and chlorfenapyr in Lonicera japonica Thunb.was established.The nitenpyram was extracted by ultrasonic extraction with acetonitrile,purified by neutral alumina packed column and detected by GC-ECD.The insect nitrile was extracted by acetone vortex,purified by neutral alumina packed column and detected by GC-ECD.The method for the determination of nitenpyram was linear in the range of 0.005 to 0.5 mg·L^-1?r=0.9993?,and the recovery at 0.02,0.1,0.2 mg·kg^-11 was between 79.14 and 98.37%.Between 3.66 and 4.39%,the detection limit of the method is 0.006mg·kg^-1;The limit of quantitation is 0.02 mg·kg^-1.the determination method of chlorfenapyr is linear in the range of 0.01⁰.5 mg·L^-1?r=0.9995?,adding 0.1,0.2,0.5 The recoveries at mg·kg^-11 ranged from83.9 to 97.6%,and the RSD ranged from 0.6 to 9.2%.The detection limit of the method was 0.007 mg·kg^-1.The limit of quantitation is 0.02mg·kg^-1.The established two pesticide detection methods have high sensitivity,high accuracy,good linearity,and meet the requirements of pesticide residue analysis.They can be used for the determination of nitenpyram and chlorfenapyr in Lonicera japonica Thunb..2.According to the pesticide residue criteria,a field experiment was conducted in the Lonicera japonica Thunb.producing area to study the residual dynamics of nitenpyram and chlorfenapyr in Lonicera japonica Thunb..The degradation laws of the two pesticides were consistent with the first-order kinetic degradation law,and the half-lives were 1.4 d and2.4 d,respectively.The final residue limit of nitenpyram is<LOQ,and the digestion rate is above 94%;the final residue limit of chlorfenapyr is between 0.3 mg·kg^-1,and the digestion rate is over 98.9%.Based on the risk assessment results and the maximum residue limit criteria,the safe harvesting periods of the two pesticides are expected to be 2 d and 11 d,respectively.