Residues of cyantraniliprole and its metabolite J9Z38 in rice field ecosystem

• A method was developed to detect of cyantraniliprole and J9Z38 in rice.
• The half-lives of cyantraniliprole were 3.2, 4.4 and 6.3 d in rice straw, respectively.
• The recommended MRL of cyantraniliprole was 0.1 mg kg−1 in brown rice.

A simple and reliable analytical method was developed to detect cyantraniliprole (HGW86) and its metabolite J9Z38 in rice straw, paddy water, brown rice, and paddy soil. The fate of cyantraniliprole and its metabolite J9Z38 in rice field ecosystem was also studied. The target compounds were extracted using acetonitrile, cleaned up on silicagel or strong anion exchange column, and analyzed by ultra-performance liquid chromatography–tandem mass spectrometry. The average recoveries of cyantraniliprole and J9Z38 in rice straw, paddy water, brown rice, and paddy soil ranged from 79.0% to 108.6%, with relative standard deviations of 1.1–10.6%. The limits of quantification of cyantraniliprole and J9Z38 were 18 and 39 μg kg−1 for rice straw, 2.8 and 5.0 μg kg−1 for paddy water, 4.3 and 6.3 μg kg−1 for brown rice, and 3.9 and 5.3 μg kg−1 for paddy soil. The trial results showed that the half-lives of cyantraniliprole were 3.2, 4.4, and 6.3 d in rice straw and 4.9, 2.0, and 6.2 d in paddy water in Zhejiang, Hunan, and Shandong, respectively. The respective final residues of cyantraniliprole and J9Z38 in brown rice were lower than 0.05 and 0.02 mg kg−1 after 14 d of pre-harvest interval. The maximum residue limit of cyantraniliprole at 0.1 mg kg−1 and dosage of 100 g a.i. hm−2, which could be considered safe to human beings and animals, were recommended.