Determination of 110 pesticide and their metabolites residues in tropical fruits using QuEChERS with amino-functionalized multi-walled carbon nanotube and liquid chromatography-tandem mass spectrometry

Combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS), an improved QuEChERS method was established based on amino-functionalized multi-walled carbon nanotubes (NH₂-MWCNTs) for the determination of 110 pesticides and their metabolites in three tropical fruits. The samples were extracted by acetonitrile, salted out by QuEChERS salt package with European standard (EN.15662) buffer system, purified by dispersed solid phase extraction (d-SPE) with NH₂-MWCNTs sorbents, analyzed at multi-reaction monitoring mode (MRM), and quantified using external standard method with matrix-matched calibration curves. The results showed good linearity (R² > 0.9902) for the 110 pesticides and their metabolites in the range of 0.002-0.2 mg/L. The limits of quantification (LOQs) ranged from 0.005 to 0.05 mg/kg. The recoveries were 61%～120%, and the relative standard deviations (RSDs) were 0.30% to 15% (n=6). This method exhibits excellent purification performance and takes less time for the sample analysis. The validation results met the requirements for qualitative and quantitative analysis of pesticides with high sensitivity, accuracy, and precision. It is suitable for rapid detection of multiple pesticide residues in tropical fruits such as litchi, longan and banana.