Determination of cyantraniliprole and its major metabolite residues in pakchoi and soil using ultra-performance liquid chromatography-tandem mass spectrometry.

A rapid, simple and reliable analytical method was developed for the determination of cyantraniliprole and its major metabolite J9Z38 in pakchoi and soil by using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample preparation approach is known as QuEChERS, which stands for quick, easy, cheap, effective, rugged and safe. Samples were extracted with acetonitrile, and cleaned up with dispersive primary and secondary amine sorbent before analysis by UPLC-MS/MS. The limit of quantitation for cyantraniliprole and J9Z38 was 0.01 mg/kg in both pakchoi and soil. Average recoveries of cyantraniliprole and J9Z38 at three fortified levels (0.01, 0.05, 0.1 mg/kg) ranged from 77.8% to 102.5% with relative standard deviation of 1.6%-8.9%. This method has been applied to the analysis of cyantraniliprole and J9Z38 residues in real pakchoi and soil samples selected from field. The results of the residue dynamic experiment showed that the half-life of cyantraniliprole ranged from 2.9 to 6.4 days in pakchoi and 8.7 to 18.2 days in soil, respectively. The final residual levels of cyantraniliprole in pakchoi and soil from Guangdong and Shanghai were below 0.20 and 0.10 mg/kg, respectively; similarly, the final residual levels of J9Z38 in pakchoi and soil from Guangdong and Shanghai were <0.07 and 0.01 mg/kg. These results will be helpful in setting maximum residue limit guidance for cyantraniliprole in pakchoi in China.