Determination of pyraclostrobin residue in wax gourd and its dietary risk assessment

Abstract

To study the residue behavior of pyraclostrobin in wax gourd, and evaluate the risk of dietary intake. Wax gourd samples were extracted with acetonitrile, purified with PSA and C18, detected by HPLC-MS/MS. In 2017, the supervised field trials of pyraclostrobin in wax gourd were carried out in Henan, Jiangsu, Sichuan, Beijing, Hunan, and Guangxi. The STMR of pyraclostrobin in wax gourd was acquired, and then the risk of dietary intake was evaluated. At the three spiked levels of 0.01, 0.1 and 1.0 mg kg-1, the average recoveries ranged from 95% to 104%, the RSDs ranged from 2.1% to 3.8%, and LOQ was 0.01 mg kg-1. The dissipation of pyraclostrobin in wax gourd in Sichuan fitted to the first order kinetics with the half-life of 4.1d. The 250 gL-1 emulsifiable concentrate of pyraclostrobin was sprayed at 150 and 225 g a.i./hm2 for 2-3 times on wax gourd. The final residue level of pyraclostrobin in wax gourd was between <LOQ and 0.11 mgkg-1. The national estimated daily intake (NEDI) of pyraclostrobin was 0.3722 mg, accounting for 19.69% of the acceptable daily intake (ADI) for general population, which means that it will not pose unacceptable risks to the health of the general population.