Characteristics of neonicotinoid and metabolite residues in Taiwanese tea leaves.

BACKGROUND: Neonicotinoids are widely used insecticides, and tea is a popular non‐alcoholic beverage in Taiwan. However, the levels of neonicotinoids in Taiwanese tea leaves remain unclear. Therefore, this study aims to understand the characteristics of neonicotinoid and metabolite residues in Taiwanese tea leaves. METHODS: In this study, 12 tea leaf samples were collected in Taiwan and extracted by solid‐phase extraction before analysis by liquid chromatography–tandem mass spectrometry. In addition, the levels of neonicotinoids were compared with the maximum residue level standards from other countries. RESULTS: In Taiwanese tea leaves, five neonicotinoids and seven metabolites were detected. Different tea species influenced the levels of neonicotinoids and their metabolites in the present study. Moreover, the levels of neonicotinoids and their metabolites in partially fermented leaves were higher than in completely fermented leaves. In Jin‐Xuan tea, the levels of neonicotinoids and their metabolites in most winter‐harvested teas were lower than in summer‐harvested teas. CONCLUSION: The residue levels of neonicotinoids and their metabolites were detectable in Taiwanese tea leaves. Moreover, different tea species, manufacturing processes, and harvest seasons might influence the levels of these pesticides. Therefore, the government should monitor the use of neonicotinoids. © 2021 Society of Chemical Industry [ABSTRACT FROM AUTHOR]