Ministry of Education, Key Laboratory of Green Pesticide and Agricultural Bioengineering.
Guizhou University, Center for Research and Development of Fine Chemicals, Guiyang 550025, China.
J AOAC Int. 2020 Nov 1;103(6):1441-1450. doi: 10.1093/jaoacint/qsaa052.
Tea is a popular traditional non-alcoholic beverage worldwide. Flonicamid is a selective systemic pyridine carboxamide insecticide that is widely used for controlling tea leafhopper in tea.
The leaching rates, dissipation dynamics, and residue levels of flonicamid and its metabolites in tea leaves during processing and transferring were investigated to validate the safe risk in tea and transfer behavior using high performance liquid chromatography-tandem mass spectrometry with a convenient pretreatment method.
The extracting method and immersion rate experiments were optimized by single factor analysis and orthogonal tests. The acetonitrile extracting solvent with 0.5% formic acid was used and optimal leaching conditions were obtained with a regime of 15 min immersion time, 100°C temperature, three immersions and a tea-to-water ratio of 1:50.
Average recoveries in processed green tea and infusions were 80.85-98.75% with relative standard deviations <5.87%. LODs and LOQs of flonicamid, 4-trifluoromethylnicotinic acid (TFNA), N-(4-trifluoromethylnicotinoyl) glycine (TFNG), and 4-trifluoromethylnicotinamide (TFNA-AM) were 0.0013-0.350 and 0.004-1 μg/g, respectively. The processing factor of flonicamid was 0.36-5.52 during green tea manufacture. The leaching rates were 22.9-97.4% from processed tea to infusion.
The risk of long-term and short-term dietary intake of flonicamid was safe in tea infusions with the risk quotient (RQ) values <1 for the Chinese consumer. This work may provide guidance for safe and reasonable consumption of flonicamid in tea in China.
The suitable leaching factors of flonicamid and its metabolites in tea infusions were optimized by orthogonal experimentation for the first time.
茶是一种全球流行的传统非酒精饮料。氟啶虫酰胺是一种选择性的系统吡啶甲酰胺类杀虫剂，广泛用于防治茶树叶蝉。
采用高效液相色谱-串联质谱法，结合简便的预处理方法，研究氟啶虫酰胺及其代谢物在茶叶加工和转运过程中的浸出率、消解动态和残留水平，验证茶叶中的安全风险和迁移行为。
通过单因素分析和正交试验优化提取方法和浸出率实验。采用含 0.5%甲酸的乙腈提取溶剂，通过 15min 浸提时间、100°C 温度、三次浸提和茶水比 1:50 的方案，获得最佳浸提条件。
加工绿茶和茶汤中氟啶虫酰胺的平均回收率为 80.85%-98.75%，相对标准偏差<5.87%。氟啶虫酰胺、4-三氟甲基烟酸（TFNA）、N-（4-三氟甲基烟酰基）甘氨酸（TFNG）和 4-三氟甲基烟酰胺（TFNA-AM）的检出限和定量限分别为 0.0013-0.350μg/g 和 0.004-1μg/g。在绿茶加工过程中，氟啶虫酰胺的加工因子为 0.36-5.52。从加工茶到茶汤的浸出率为 22.9%-97.4%。
在中国消费者中，氟啶虫酰胺在茶饮料中的风险商（RQ）值<1，长期和短期饮食摄入氟啶虫酰胺的风险是安全的。本研究可为中国氟啶虫酰胺在茶中的安全合理消费提供指导。
首次通过正交试验优化了氟啶虫酰胺及其代谢物在茶饮料中的适宜浸出因子。
