title: Enantioselective Dissipation of Acephate and Its Metabolite, Methamidophos, during Tea Cultivation, Manufacturing, and Infusion.
abstract: The enantioselective dissipation of acephate and its metabolite, methamidophos, was investigated during tea cultivation, manufacturing, and infusion, using QuEChERS sample preparation technique and gas chromatography coupled with a BGB-176 chiral column. Results showed that (+)-acephate and (-)-acephate dissipated following first-order kinetics in fresh tea leaves with half-lives of 1.8 and 1.9 days, respectively. Acephate was degraded into a more toxic metabolite, methamidophos. Preferential dissipation and translocation of (+)-acephate may exist in tea shoots, and (-)-methamidophos was degraded more rapidly than (+)-methamidophos. During tea manufacturing, drying and spreading (or withering) played important roles in the dissipation of acephate enantiomers. The enantiometic fractions of acephate changed from 0.495-0.496 to 0.479-0.486 (P ≤ 0.0081), whereas those of methamidophos changed from 0.576-0.630 to 0.568-0.645 (P ≤ 0.0366 except for green tea manufacturing on day 1), from fresh tea leaves to made tea. In addition, high transfer rates (>80%) and significant enantioselectivity (P ≤ 0.0042) of both acephate and its metabolite occurred during tea brewing.
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences , Hangzhou 310008, China.|Graduate School of Chinese Academy of Agricultural Sciences , Beijing 100081, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Pan
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences , Hangzhou 310008, China.|Key Laboratory of Tea Quality and Safety & Risk Assessment, Ministry of Agriculture, Hangzhou 310008, China.
authors.forename: Hongping
authors.initials: H
authors.lastname: Chen
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences , Hangzhou 310008, China.|Key Laboratory of Tea Quality and Safety & Risk Assessment, Ministry of Agriculture, Hangzhou 310008, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Wang
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences , Hangzhou 310008, China.|Key Laboratory of Tea Quality and Safety & Risk Assessment, Ministry of Agriculture, Hangzhou 310008, China.
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences , Hangzhou 310008, China.|Key Laboratory of Tea Quality and Safety & Risk Assessment, Ministry of Agriculture, Hangzhou 310008, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Tea Research Institute, Chinese Academy of Agricultural Sciences , Hangzhou 310008, China.|Key Laboratory of Tea Quality and Safety & Risk Assessment, Ministry of Agriculture, Hangzhou 310008, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
keywords: acephate; enantioselectivity; infusion; manufacturing; metabolite; tea