| Diamide insecticides are a new class of insecticides targeting the ryanodine receptors,it disrupts intracellular Ca2+homeostasis by activating the ryanodine receptors on the endoplasmic reticulum of insect cells,leading to blocked regulation of muscle contraction,exhibiting paralysis,spasm,palsy,and eventually death.Tetrachlorantraniliprole is an anthranilic diamide insecticide,which has a broad application prospect due to its novel mode of action,low toxicity to mammals and excellent efficacy against lepidoptera pests.At present,studies on the analytical methods of tetrachlorantraniliprole in agricultural products at home and abroad mainly focus on the parent compound,and relevant studies on its metabolites have not been reported.Leafy vegetables have a short growth cycle and are rich in nutrients.To ensure that vegetables can grow healthily,using chemical pesticides is one of the main means of control.However,with the irrational application of pesticides in the planting process,it has led to the frequent occurrence of excessive pesticide residues,even endangering the health of consumers and causing negative effects on the environment.Therefore,the timely establishment of residue analysis methods for pesticides and their metabolites of toxicological significance produced in the field environment after use,as well as the monitoring and control of their residues in food,can help reduce the associated dietary and environmental risks.In this study,a residue analysis method was developed for tetrachlorantraniliprole and its metabolites in lettuce,spinach,and soil.The developed method was applied to a dissipation field study.Under field conditions,terminal residues of tetrachlorantraniliprole and its metabolites in lettuce,spinach,and soil were determined,the scientific basis for establishing maximum residue limit for tetrachlorantraniliprole in lettuce and spinach.Based on the terminal residues results,the dietary risk of tetrachlorantraniliprole in lettuce and spinach was assessed.The specific findings of the study are as follows:1.A residue analysis method for determination of tetrachlorantraniliprole and its three metabolites P499a,P499b,and P517 in lettuce,spinach,and soil was developed.The method was optimized on the basis of Qu ECh ERS method,vegetable samples were extracted by acetonitrile then cleaned up by a new carbonous material Carbon S,while soil was purified using octadecyl silica.Analyte detection was carried out using ultrahigh-performance liquid chromatography-tandem mass spectrometry.The intra-day（n=5）and inter-day（n=15）mean recoveries of tetrachlorantraniliprole and its metabolites in lettuce,spinach,and soil were70.6%-96.3%,and 74.7%-93.3%at spiking levels of 0.01,0.1,and 1 mg/kg,respectively,while the relative standard deviations were less than 18.6%.The performance of the developed method conforms to the requirements of the agricultural standard of pesticide residue analysis,and it is suitable for detection of tetrachlorantraniliprole and its metabolites in the three matrices.2.The dissipation of tetrachlorantraniliprole were investigated by using the established analytical method.The results show that in greenhouse experiments,half-lives of tetrachlorantraniliprole in lettuce,spinach,and soil were 3.4,6.4,and 23.9 d,respectively.In field experiments,half-lives of tetrachlorantraniliprole in lettuce,spinach,and soil were 4.0,5.5,and 13.3 d,respectively.Tetrachlorantraniliprole has an elimination half-life of less than 30 d and is an easily degradable pesticide.3.The terminal residues of tetrachlorantraniliprole and its metabolites（expressed as tetrachlorantraniliprole）in lettuce,spinach,and soil were determined.The results showed that in greenhouse experiments,the total final residues of tetrachlorantraniliprole and its metabolites in lettuce,spinach,and soil samples were 1.198-2.979,1.444-3.909,and 0.012-0.155 mg/kg,respectively.In field experiments,the total final residues of tetrachlorantraniliprole and its metabolites in lettuce,spinach and soil samples were 0.443-1.724,2.339-4.178,and 0.029-0.146mg/kg,respectively.The residue definition of tetrachlorantraniliprole only specifies the residue of the parent,but not its metabolite in China.In view of the detection of the metabolite of tetrachlorantraniliprole in the test results,and the toxicity of its metabolite is comparable to that of the parent,therefore,it is proposed to include its metabolite in the residue definition of tetrachlorantraniliprole.4.The dietary risk of tetrachlorantraniliprole in lettuce and spinach was assessed based on final residue data.The results showed that the long-term dietary risk quotients of tetrachlorantraniliprole in lettuce and spinach were 30.51%and 32.68%,respectively,which were less than 100%and the dietary risk was acceptable.Based on the results of the analysis,the recommended maximum residue limit for tetrachlorantraniliprole in lettuce and spinach in China was 5 mg/kg.10%tetrachlorantraniliprole suspension was used for the control of lepidoptera pests at the recommended dose of 600 g/hm2（60 g a.i./hm2）with three applications and pre-harvest interval of 3 d.The residues of tetrachlorantraniliprole in lettuce and spinach at harvest were below the recommended maximum residue values and safe for consumption. |
