Seven neonicotinoids and twenty-two metabolites in seven food matrices by optimized QuEChERS-HPLC-MS/MS and dietary...

In this study, a modified QuEChERS method coupled with high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) was developed to analyze the residues of seven neonicotinoid insecticides (NEOs) and twenty-two metabolites (m-NEOs) in seven matrices. Acetonitrile containing 1% formic acid was used for sample extraction. The linearities were acceptable (R² ≥ 0.9912) within the range of 10-1000 μg mL^-1. Average recoveries were 74.5%-107.6% at three spiked levels (10, 100, and 500 μg kg^-1), with RSDs between 0.8% and 14.1%. The LODs were below 1.94 μg kg^-1, and the LOQs did not exceed 6.45 μg kg^-1. In 175 samples, 39.4% samples contained at least one NEO or m-NEO. Notably, thiamethoxam, acetamiprid, imidacloprid, and dinotefuran were the four most frequently detected NEOs in all samples. Moreover, these results implied that the first two generations of NEOs still played an important role in pest control. Both chronic and acute risks were acceptable.