Aijuan Bai1, Ang Chen2, Wuying Chen2, Shaowen Liu3, Xiangwen Luo2, Yong Liu1,2, Deyong Zhang1,2. 1. Longping Branch, Graduate School of Hunan University, Changsha, 410125, China. 2. Hunan Plant Protection Institute, Hunan Academy of Agricultural Science, Changsha, 410125, China. 3. Hunan institute of agricultural environment and ecology, Hunan Academy of Agricultural Science, Changsha, 410125, China.
Abstract
BACKGROUND: Tolfenpyrad and dinotefuran are two representative pesticides used for pest control in tea garden. The application may bring about potential risk to consumers health. Therefore, it is essential to investigate the residue behavior, transfer and risk assessment of tolfenpyrad, dinotefuran and metabolites from tea garden to teacup. RESULTS: An effective analytical method was established and validated to simultaneously determine tolfenpyrad, dinotefuran and its metabolites (DN and UF) in tea. The average recoveries of tolfenpyrad, dinotefuran, DN and UF were 72.1-106.3% with the relative standard deviations (RSDs) lower than 11.8%. On basis of the proposed method, the dissipation of tolfenpyrad and dinotefuran in fresh tea leaves were following first-order kinetics models with half-lives of 4.30-7.33 days and 4.65-5.50 days, respectively. With application amounts of 112.5-168.75 g a.i./ ha for once or twice, the terminal residues of tolfenpyrad and total dinotefuran in green tea were lower than 19.6 mg/kg and 7.13 mg/kg, respectively, which were all below their corresponding maximum residue limits (MRLs). The leaching rates of tolfenpyrad and total dinotefuran during the tea brewing were 1.4-2.3% and 93.7-98.1%, respectively. CONCLUSION: Tolfenpyrad and dinotefuran in tea were easily degraded. The RQc and RQa value for tolfenpyrad were 37.6% and 11.7%, and which were much higher than dinotefuran with 24.7% and 1.8%, respectively. The data indicated there was no significant health risk in tea for consumers at the recommended dosages. The results will offer scientific data on the reasonable use of tolfenpyrad and dinotefuran to ensure the safety of drinking tea. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
BACKGROUND: Tolfenpyrad and dinotefuran are two representative pesticides used for pest control in tea garden. The application may bring about potential risk to consumers health. Therefore, it is essential to investigate the residue behavior, transfer and risk assessment of tolfenpyrad, dinotefuran and metabolites from tea garden to teacup. RESULTS: An effective analytical method was established and validated to simultaneously determine tolfenpyrad, dinotefuran and its metabolites (DN and UF) in tea. The average recoveries of tolfenpyrad, dinotefuran, DN and UF were 72.1-106.3% with the relative standard deviations (RSDs) lower than 11.8%. On basis of the proposed method, the dissipation of tolfenpyrad and dinotefuran in fresh tea leaves were following first-order kinetics models with half-lives of 4.30-7.33 days and 4.65-5.50 days, respectively. With application amounts of 112.5-168.75 g a.i./ ha for once or twice, the terminal residues of tolfenpyrad and total dinotefuran in green tea were lower than 19.6 mg/kg and 7.13 mg/kg, respectively, which were all below their corresponding maximum residue limits (MRLs). The leaching rates of tolfenpyrad and total dinotefuran during the tea brewing were 1.4-2.3% and 93.7-98.1%, respectively. CONCLUSION: Tolfenpyrad and dinotefuran in tea were easily degraded. The RQc and RQa value for tolfenpyrad were 37.6% and 11.7%, and which were much higher than dinotefuran with 24.7% and 1.8%, respectively. The data indicated there was no significant health risk in tea for consumers at the recommended dosages. The results will offer scientific data on the reasonable use of tolfenpyrad and dinotefuran to ensure the safety of drinking tea. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.