| Thiamethoxam and clothianidin were the neonicotinoids that replaced conventional highly toxic pesticides, used in a very wide scope and application prospects. Many countries had detection limit request of thiamethoxam and clothianidin on agricultural products, and there were no related standards in China in present. In order to prevent the abuse of pesticides that were harm to the public in China as well as experience in international trade barriers,early establishment of thiamethoxam and clothianidin amines in agricultural products in the testing standards would help to better regulate and control the use of pesticides. Purpose of this paper was to establish detection method of thiamethoxam and clothianidin in agricultural products. First, thiamethoxam, clothianidin HPLC analysis and UPLC-MS/MS analysis instrument approaches were established. However, because there are a wide range of sample matrix of agricultural products, HPLC instruments detection limits were high and difficult to eliminate sample matrix interferences, UPLC-MS/MS on thiamethoxam, clothianidin analysis was finally selected. Samples were ertracted by ultrasonic extraction with organic solvents or liquid-liquid extraction after homogenization. Samples were cleaned by QuEcHERS packed solid phase dispersion, and the results was analysised by external standard method. UPLC-MS/MS detection of thiamethoxam, clothianidin pesticide residues in 14 kinds of agricultural products which contain vagetables and fruits etc. was established. The average recovery of thiamethoxam was 74.19%~107.9%, recovery of clothianidin was 79.21%~106.2%. Among 14 kinds of agricultural products, the detection limit of the thiamethoxam was 0.051~0.261μg/kg, the detection limit of clothianidin was 0.066~0.210μg / kg.Methodological study showed that UPLC-MS/MS method is simple, qualitative, accurate, reliable, sensitive, reproducible, highly practical and feasible. |
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