Center of Agricultural Product Safety, Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, China.
Key Laboratory of Tea Biology and Resources Utilization, Ministry of Agricultural, Hangzhou, China.
J Sci Food Agric. 2021 Aug 15;101(10):4118-4124. doi: 10.1002/jsfa.11047. Epub 2021 Feb 3.
Pymetrozine is a widely used pesticide. It is challenging to analyze and difficult to manage due to the large gap in its global maximum residue limits (MRLs) in tea. The development of a high-efficiency detection method for the evaluation of the transfer of residual pymetrozine from tea plantations to tea cups is therefore of prime significance.
An analytical method for the determination of pymetrozine residues in tea was established based on Cleanert PCX solid-phase extraction. The average recoveries were 72.2-93.7%, with relative standard deviations (RSDs) of less than 12%. The limits of quantification (LOQs) were 0.005 mg·kg in fresh tea leaves and dry tea, and 0.00025 mg·L in tea brew. Pymetrozine degraded rapidly in tea plants with a half-life (t ) of 1.9 days in open tea plantations, and decreased by 9.4-23.7% in the green tea-processing procedure, which was concentration dependent. The residual pymetrozine levels in green tea collected at 6 and 21 days were below the MRLs in China and EU at a dosage of 30 g a.i. ha , respectively. The leaching rates of pymetrozine from dry tea to tea brew were 58.7-96.3%. Hazard quotient (HQ) values of pymetrozine were significantly <100% when tea shoots were plucked in 6 days, which indicated a negligible risk to humans.
This work allows the determination of residual pymetrozine in tea and illustrates a low intake risk with the use of pymetrozine in tea plantations. It could serve as reference for further regulation consideration for maximum residue limits (MRLs). © 2020 Society of Chemical Industry.
吡丙醚是一种广泛使用的农药。由于其在全球茶叶中的最大残留限量（MRL）差距较大，因此分析和管理都具有挑战性。因此，开发一种高效的检测方法来评估残留吡丙醚从茶园向茶杯中的转移情况具有重要意义。
建立了基于 Cleanert PCX 固相萃取的茶叶中吡丙醚残留的分析方法。平均回收率为 72.2-93.7%，相对标准偏差（RSD）小于 12%。新鲜茶叶和干茶叶中的定量限（LOQ）为 0.005 mg·kg，茶汤中的 LOQ 为 0.00025 mg·L。吡丙醚在开放茶园中的茶树中迅速降解，半衰期（t ）为 1.9 天，在绿茶加工过程中减少了 9.4-23.7%，且与浓度有关。在 30 g a.i.ha 的剂量下，分别在 6 天和 21 天收集的绿茶中的残留吡丙醚水平低于中国和欧盟的 MRL。吡丙醚从干茶到茶汤的浸出率为 58.7-96.3%。当在 6 天内采摘茶芽时，吡丙醚的危害商（HQ）值显著<100%，这表明对人类的风险可以忽略不计。
本工作可以测定茶叶中的残留吡丙醚，并说明了在茶园中使用吡丙醚时摄入风险较低。这可为进一步考虑最大残留限量（MRL）的监管提供参考。© 2020 英国化学学会。
