Dissipation Kinetics of Pymetrozine in Tomato Field Ecosystem

Background: The food safety is one of the top priorities in the protection of public health. Pesticide residue has environmental and human health impact so, studding the behavior and dissipation of pesticides on foods is necessary. Objectives: This paper aimed to study the dissipation kinetics of pymetrozine to assess its effect in the ecosystem of tomato field, to expose residual dissipation behavior. Materials and methods: In a tomato-field ecosystem, tomato samples were collected after pymetrozine application in different time intervals 0, 1, 3, 5, and 7 days. The dissipation kinetics and residual behavior of insecticide were analyzed based on a QuEChERS method and quantified by high-performance liquid chromatography combined with photodiode array detection (HPLC-DAD). Results: The average recovery from tomatoes was 90.75% (88.5 - 93%), and 85 - 87.5% from soil. The coefficient variation of the method (CV %) was less than 7% in tomatoes, and less than 12%. in soil, ranged from 1.27% to 4.77% for repeatability. The low detection limit (LOD) and limit of quantitation (LOQ) of pymetrozine were determined to be 0.01 and 0.03 mg/kg, respectively. The dissipation kinetics of pymetrozine residue was C = 1.504 e−0.528t in tomato and C= 11.82 e−0.4082t in soil, in addition, residues half-lives were 1.31, and 2 days, respectively. The pre-harvest interval (PHI) of pymetrozine on tomatoes was 3 days. The recommended dosage could be considered a safe dosage for humans. Conclusion: This study would contribute to provide information on safe and proper use of the pesticide.