Journal of Food Safety and Quality

Objective To establish an analytical method for the determination of flonicamid residues in tea and assess the dietary intake risk of flonicamid in tea. Methods Flonicamid residues in tea were extracted using acetonitrile, followed by dehydration and salting out with anhydrous MgSO4 and sodium acetate. The supernatant was purified using anhydrous MgSO4, C18, primary-secondary amine (PSA), and graphitized carbon black (GCB) as adsorbents. Analysis was performed using ultra performance liquid chromatography-tandem mass spectrometry in multiple reaction monitoring mode with positive ionization. Quantification was achieved using matrix-matched external standards. Dietary intake risk assessment was conducted based on residue trial results and the dietary structure of the Chinese population. Results Flonicamid had a good linear relationship (r≥0.9999) within a certain concentration range. At levels of 0.01, 0.50, 20.00 and 30.00 mg/kg, the average recovery rates of tea (dry and fresh) ranged from 83.9%–93.6%, with relative standard deviations of 1.1%–5.3%. The limit of quantitation was 0.01 mg/kg. The final residue test and degradation test showed that the residual amount of flonicamid on tea was mainly affected by the combined effects of application dose and harvesting interval. The half-lives of flonicamid in fresh and dry tea in various regions were between 0.8–4.0 d and 0.8–5.1 d, respectively, indicating that it was an easily degradable pesticide. The results of the dietary assessment showed that the estimated daily intake of flonicamid through tea consumption for adults over 18 years old was between 0.74–0.81 μg/(kg·bw·d), which accounted for 1.05% to 1.16% of acceptable daily intake; combining the registration status of pesticides in China and the existing residue limits, the national estimated daily intake of flonicamid for the general population was 58.5193 μg/(kg·bw·d), which accounted for 83.6% of the acceptable daily intake. Flonicamid had low acute toxicity, and the probability of causing acute dietary risk was minimal. Therefore, there was no need to conduct an acute dietary risk assessment. 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 flonicamid does not pose an unacceptable risk to the general population.

tea; flonicamid; residue; dietary intake risk assessment