Residue Degradation And Dietary Risk Assessment Of Broflanilide In Maize

Maize is China’s main food crop,not only has high nutritional value but also good environmental adaptability,so it is widely grown,but it is susceptible to pests and diseases during growth,and the use of pesticides ensures the quality and yield of maize.Broflanilide is a metadiamide insecticide jointly developed by BASF and Mitsui Chemicals for the control of lepidoptera and Coleoptera pests in cereals and vegetables.Although Broflanilide plays an important role in agricultural production,it poses certain risks to humans and the environment,such as chronic toxicity to non-target zebrafish.Therefore,the field residue test of Broflanilide was carried out,and a high performance liquid chromatography tandem mass spectrometry method for Broflanilide on maize was established,and the digestion dynamics and final residues in the maize planting system were studied by this method,which provided theoretical guidance for the safe use of Broflanilide on maize.At the same time,it provides a scientific basis for the formulation of the maximum residue limit on maize and conducts dietary risk assessment The research content and main conclusions are as follows:1.A residue analysis method for high performance liquid chromatography tandem mass spectrometry（HPLC-MS/MS）combined with QuEChERS in fresh maize,maize,plants and soil was established.In this study,the mass spectrometry parameters and mobile phase ratio were optimized,the effects of different extractants and extraction volumes on the recovery rate of Broflanilide were compared,and the types and dosages of purification agents were screened.The results showed that the average recovery of different levels of Broflanilide in each matrix was between 95.9%～108.7%,the relative standard deviation（RSD）was between 1.1%～12.7%,the limit of detection（LOD）was 3.92×10^-4ng,and the limit of quantification（LOQ）was 0.01 g/kg,which met the requirements of pesticide residue analysis and detection,and could be applied to the detection of Broflanilide residue in maize.2.In 2021,the digestion dynamic test of 10%Broflanilide suspension in maize plants and soil was carried out in Chifeng City,Inner Mongolia Autonomous Region,Hailun City,Heilongjiang Province,and Changchun City,Jilin Province.The results showed that the digestion dynamics of Broflanilide in maize plants and soil conformed to the first-order kinetic equation,and the half-lives were 4.56～5.64 d and 11.55～20.39 d,respectively,which were less than 30 d,which were easily degradable pesticides(T_1/2<30 d).3.In 2021,the final residue test of 10%Broflanilide suspension on maize was carried out in Chifeng City,Inner Mongolia Autonomous Region,Hailun City,Heilongjiang Province,and Changchun City,Jilin Province.The results showed that at doses of 240 mL/ha（24 g a.i./ha）and360 mL/ha（36 g a.i./ha）,administered 2 and 3 times,with sampling intervals of 14,21 and 28days,the residue of Broflanilide in maize was less than 0.01 mg/kg,the residue in fresh maize was less than 0.01～0.040 mg/kg,and the residue in maize plants was 0.152～1.407 mg/kg.The residue in maize soil was less than 0.01～0.057 mg/kg.4.Under the condition of-20°C protected from light,the storage stability of Broflanilide in fresh maize,maize and plant samples was studied,and the sample sampling interval was set to 0,30,90 and 180 days.The results showed that the average degradation rate of Broflanilide in fresh maize matrix was 9.61%～22.7%,which could be stably stored for 180 days.The average degradation rates in maize and plant substrate were 3.75%～11.69%and13.18%～23.40%,which could be stably stored for 90 days.5.Combined with the results of field tests,the registration of Broflanilide in China and the domestic dietary structure,the long-term dietary intake risk assessment of Broflanilide was carried out,and the evaluation results showed that the RQ values of fresh maize and maize were8.46%,much less than 100%,indicating that it would not pose an unacceptable risk to public health.It is recommended that 10%Broflanilide suspension be used to control maize pests,the application dose is 240 mL/ha（24 g a.i./ha）,the application is up to 2 times on maize,the recommended safety interval is 14 days,and the MRL value of Broflanilide is recommended to be 0.01mg/kg in maize and 0.05mg/kg in fresh maize.