Abstract
A new method for screening 300 pesticide residues in fruit‐, vegetable‐, and cereal‐based baby foods by an improved QuEChERS purification method based on amino‐functionalized multiwalled carbon nanotubes (NH2‐MWCNTs) combined with gas chromatography‐electrostatic field orbitrap high‐resolution mass spectrometry (Orbitrap GC‐MS) was developed. The samples were extracted with acetonitrile (dry sample soaked in water first for activation), purified by dispersed solid phase extraction (d‐SPE) tube modified by NH2‐MWCNTs, and detected by Orbitrap GC‐MS. Qualitative analysis was carried out by retention time and accurate mass measurements in full scan mode, and external standard method for quantitation was performed using matrix‐matched standard calibration, which could effectively eliminate matrix interference. Method validation was performed on commercially available fruit‐, vegetable‐, and cereal‐based baby foods. Good linearity was achieved for 300 pesticides in the concentration range of 5 to 500 μg/kg with correlation coefficients greater than 0.995 0. The limits of detection (LOD) were 0.3–3.0 μg/kg, and the limits of quantification (LOQ) were 1.0–10.0 μg/kg. The average recoveries on 10, 50, and 200 μg/kg spiked levels were in the range of 72.8%–123.4% in three types of samples, with relative standard deviations (RSDs) of 2.0%–13.3%. The proposed method, with simple pretreatment, highly sensitivity, high precision, and accuracy, is suitable for simultaneous analysis of 300 pesticide residues in baby foods. This method provides a reference for accurate screening of low pesticide residues in baby food.