Residue Analysis And Dietary Risk Assessment Of Lufenuron In Leek And Soil

Chinese leek is one of the traditional green vegetables in China,which can promote the peristalsis of the intestines,change kidney deficiency and improve masculinity,good for liver and stomach health,make the air smooth and adjust the blood,and improve self-immunity.In addition,Chinese leek also has a certain anti-inflammatory effect.In recent years,due to the excessive use of pesticides by farmers,the quality of Chinese leek has been declining.Incidents of"poisonous Chinese leek"also often occurred.In order to ensure people's food safety and protect the yield of Chinese leek,it is crucial to detect and control the pesticides exceeding the MRLs.In this study,residue analysis of Lufenuron on Chinese leek was used to determine the residual amount of Lufenuron in Chinese leek and soil,which provided technical support for the study of Lufenuron residue in Chinese leek.It also provided a reasonable scientific basis for formulating the MRL value of Lufenuron and the safe use of Chinese leek.This study established a high performance liquid chromatography-tandem mass spectrometry?HPLC-MS/MS?method for simultaneous determination of Lufenuron in Chinese leek and soil.The instrument conditions and pretreatment methods were optimized and screened.Final separation with an Agilent Zorbax RRHD Eclipse Plus C₁₈8 chromatographic column,and the mobile phase was acetonitrile:water?0.1%formic acid and 5 mmoL ammonium acetate?at a flow rate of 0.3 mL/min.Multi-reaction monitoring mode?MRM?was adopted,and the external standard method was used for quantitative analysis,the Lufenuron in the Chinese leek and soil was extracted with acetonitrile,purified by QuEChERS.The results showed that the Lufenuron had a good internal linearity in the concentration range of 0.001⁰.5 mg/L,and the correlation coefficient was 0.9968.The recovery test of different levels was carried out.The average recovery rate of the Chinese leek plants was 75.3⁸0.4%,and the relative standard deviation was 2.8¹0.4%;the average recovery rate in Chinese leek soil is 70.3⁸9.5%,and the relative standard deviation is 1.6³.6%.Under the above detection conditions,the minimum detectable amount of Lufenuron was 4.2×10^-4 ng,and the lowest detectable quality of Lufenuron in Chinese leek plants and soil was 0.01 mg/kg.In the paper,the residue of Lufenuron in leek plant and soil was also studied.From 2016 to2017,two-year fields experiment was conducted in Inner Mongolia and Shandong,which results shows that the half-life of Lufenuron in leek plant was 1.6⁴.2 d,and the half-life of Lufenuron in soil was 10.9⁴0.4 d.The final residue of Lufenuron in leek plant and soil were studied,when 1%Lufenuron granules were used in plants and soil in Inner Mongolia and Shandong at low doses 22500g/hm²?225 g a.i./hm²?and high doses 33750 g/hm²?337.5 g a.i/hm²?,respectively,administered once or twice while the interval of administration was 7d,the final residue of Lufenuron in leek plant was 0.010⁰.080 mg/L and 0.056⁵.384 mg/L in the soil.In the dietary risk assessment of Lufenuron in leek,it is found that the risk quotient is 1.32×10^-3,which is far below 1,and represents an acceptable risk.According to the research results,it is suggested that the MRL value of Lufenuron in leek should be 0.1 mg/L in China,and the recommended dosage is 22500 g/hm²?225 g a.i./hm²?that according the higher dose of the prescribed dose when is used the 1%lufenuron granules,application frequency is the one time and the safety interval is 7d.