Abstract:

To monitor chlorantraniliprole and clothianidin residues in rice, a QuEChERS method based on dispersive solid-phase extraction combined with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established for the simultaneous determination of chlorantraniliprole and clothianidin residues in brown rice, rice husk and straw. The samples were extracted by shaking with acetonitrile water solution, purified by PSA or C₁₈, detected under UPLC-MS/MS multiple-reaction monitoring mode, and quantified by external standard method. The results showed that the best extraction solvent for chlorantraniliprole and clothianidin was 50% acetonitrile water solution, and the extraction method was shaking extraction. C₁₈ was selected as the purifying agent for the brown rice extract, and PSA was used as the purifying agent for the extraction solvent of rice husk and straw. Good linear relations were obtained in the range of 0.1-100 μg/L for chlorantraniliprole and in the range of 0.1-500 μg/L for clothianidin, and the correlation coefficient R² was greater than 0.99. The average recovery of the two pesticides in brown rice, rice husk and straw were between 83.2% and 105.4%, and the relative standard deviations were between 1.2% and 10.1%. The limit of quantitation of chlorantraniliprole and clothianidin in brown rice was 0.005 mg/kg, and the limit of quantitation in rice husk and straw were 0.025 mg/kg. The pretreatment process of the method is simple, rapid and highly sensitive. The method is suitable for the simultaneous detection of chlorantraniliprole and clothianidin residues in brown rice, rice husk, and straw.

Key words: chlorantraniliprole, clothianidin, dispersive solid-phase extraction, high performance liquid chromatography-tandem mass spectrometry, rice