Enantioselectivity and residue analysis of fipronil in tea (Camellia sinensis) by ultra-performance liquid chromatography Orbitrap mass spectrometry

This study aimed to determine the residues of fipronil, metabolites, and enantiomers in tea (Camellia sinensis) during tea planting and green tea manufacture. An AD-RH chiral column was used to separate the fipronil enantiomers. During tea planting, the half-lives of the sum of fipronil and metabolites were similar to those of fipronil, which were 2.37 and 3.88 days for tea shoots and mature leaves, respectively. The residues of fipronil and its metabolites increased 2.3–3.6-fold during green tea manufacture. The values for the processing factors of fipronil and metabolites ranged from 1.0 to 2.1. A slightly significant enantioselectivity of (R)- and (S)-fipronil was observed during tea planting and green tea manufacturing. The residue pattern indicated that fipronil should not be applied in tea gardens due to its long persistence. The maximum residual limits of fipronil and metabolites at 2 μg kg⁻¹ were considered optimal.