Risk Assessment Of Nicotine Pesticides In Peach Production In Tianjin

During the whole growth period of peach,pests and diseases will greatly affect the yield and quality of peach.The five neonicotinoid pesticides of acetamiprid,thiamethoxam,clothianidin,imidacloprid and dinotefuran have killing power.The wide spectrum of insects,low toxicity,and long duration of effect have significant effects on the control of peach tree insect pests.Therefore,neonicotinoid pesticides are widely used by fruit farmers in the control of fruit tree pests.In this paper,five neonicotinoid pesticides and their metabolite residues in peach samples were determined by establishing the detection method,so as to evaluate the safety risk of five neonicotinoid pesticides and their metabolism residues in peach samples.The research results of this paper are as follows:1.The screening method of five neonicotinoid pesticides and their metabolite in peach was setted with HPLC.The Qu ECh ERS method was used to investigate the extraction and purification conditions,which not only simplified the experimental method,but also achieved good experimental results.The results showed that the concentration of mixed standard solution was in the range of 0.01 to 1.00mg/kg,the five neonicotinoid pesticides and their metabolite have a good linear relationship,the correlation coefficient was greater than 0.9902,the detection limit of five neonicotinoid pesticides and their metabolism was 0.01 to0.03mg/kg,and the quantitative limit was 0.02 to 0.06mg/kg.The standard curve was used to quantitatively calculate the recoveries of five neonicotinoid pesticides and their metabolites in peach samples from 63.5% to 95.9%,and the relative standard deviations(RSDs)were between1.8% to 8.3%.2.A qualitative and quantitative analysis method for liquid chromatography mass spectrometry was established,and the optimized Qu ECh ERS method was used to detect five neonicotinoid pesticides(acetamiprid,thiamethoxam,clothianidin,imidacloprid and dinotefuran)and their metabolites(6-chloronicotinic acid,UF,DN)in the peach,.The results showed that when the 0.01 to 1 mg/L mixed standard solution was added to the peach,it showed a good linear relationship,the correlation coefficients R2 were all greater than 0.9902,the detection limit was 0.14 to 0.40μg/kg,and the limit of quantification was 0.43 to1.13μg/kg.The recoveries of the five neonicotinoid pesticides and their metabolites measured in peach were in the range of 67.1% to 98.8%,and the relative standard deviations(RSDs)were in the range of 1.6% to 8.2%.At the same time,the detection rate of neonicotinoid pesticides in peach samples was about 95%,the residues of thiamethoxam,clothianidin and6-chloronicotinic acid were high,The detection rates of other pesticides were between 0% to10%,the residue level was generally low.3.The dietary risk of five new nicotine pesticides and their metabolites in peach was analyzed.Chronic and acute dietary risks were used to assess the risk of pesticide intake.By sorting pesticide residues and the risks of the samples,and estimating the maximum residue limits.The results showed that all of the five neonicotinoid pesticides and their metabolites were low toxic pesticides,except 6-chloronicotinic acid had no ADI value and ARf D value could not be used to calculate the dietary intake risk,the risk values of chronic dietary exposure for the other 4 pesticides were significantly lower than 100%.The risk of acute dietary exposure was significantly lower than 100% except imidacloprid,Secondly,the recommended maximum residue limit values for acetamiprid,thiamethoxam,clothianidin,imidacloprid,dinotefuran were proposed;In the last risk ranking,thiamethoxam score was greater than 20,indicating high risk pesticide.The scores of acetamiprid and imidacloprid ranged from 15 to 20,indicating medium risk pesticide.Clothianidin and dinotefuran,with scores less than 15,low-risk pesticides.Ninety percent of the peach matrix is medium,low,and extremely low risk samples;this indicates that the pesticide residues in peaches are within acceptable limits and will not affect consumers’ health.