Determination of 20 neonicotinoid insecticides and their metabolites in infant foods by a modified QuEChERS method combined with HPLC-MS/MS

A rapid, effective, and reliable method for the simultaneous detection of 20 neonicotinoids and their metabolites in infant foods has been developed using liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). To improve the accuracy and precision of the method, different extraction solvents, extraction methods, and adsorbents were evaluated to achieve a better recovery and clean-up effect. Under optimized conditions, the samples were extracted with acetic acid acidified acetonitrile/ethyl acetate by ultrasonication, and then were cleaned with reduced graphene oxide@Fe 3 O 4 (rGO@Fe 3 O 4 ) and primary and secondary amine (PSA) through a QuEChERS step. A matrix-matched calibration method was applied for quantification. In three different food matrixes (vegetable & fruit cookies, grain rice cereals, and vegetable purees), all the target compounds showed good linearity, both with values of r 2 > 0.99. The average recovery of all neonicotinoids ranges from 68.0%~106.5% (vegetable & fruit cookies), 70.4%~105.4% (grain rice cereals), and 71.9%~107.4% (vegetable purees). Relative standard deviations were all < 15% for intraday and interday precision. The values of limit of detection and limit of quantification were, respectively, ranging from 0.02-0.35 μg kg -1 and 0.1-1.0 μg kg -1 . The presented method was applied to the analysis of real samples.