| Objective ? A method for analyzing the residues of flonicamid in tea leaves was established, and the dietary intake risk of flonicamid in tea leaves was. Methods The residues of flonicamid in tea were extracted with acetonitrile, and then dehydrated and salted with anhydrous MgSO4 and sodium acetate. The supernatant is obtained by using MgSO4 Purification with C18, primary secondary amine (PSA), and graphitized carbon black (GCB), analyzed by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), detected by multi reactive ion monitoring mode (MRM), positively ionized (ESI+), and quantified by matrix matched external standards. Results Flonicamid has a good linear relationship (r ≥ 0.9999) within a certain concentration range. At levels of 0.01, 0.5, 20 and 30 mg/kg, the average recovery rate of tea leaves (dry) and (fresh) ranged from 84% to 94%, with a relative standard deviation of 1.1% to 5.3%. The limit of quantification (LOQ) is 0.01 mg/kg. The final residue test and degradation test showed that the residue of flonicamid on tea was jointly affected by the application dose and interval. The half-lives of flonicamid in fresh and dry tea in various regions were between 0.9~4.0 d and 0.8~5.1 d, respectively, indicating that it is an easily degradable pesticide.The results of the dietary assessment show that the estimated daily intake (EID) of flonicamid through tea consumption for different age is between 0.74-0.81 μg/kg bw/d, which accounts for 1.05%～1.16% of acceptable daily intake; combining the registration status of pesticides in China and the existing residue limits, the national estimated daily intake(NEID) of flonicamid for the general population is 8.48 μg/kg bw/d, which accounts for 83.5% of the acceptable daily intake. Conclusion: This method has simple pretreatment steps, high accuracy, and high sensitivity, and can be used for the detection of flonicamid residues in tea. Upon evaluation, it has been determined that flupyradifur does not pose an unacceptable risk to the general population. |
