[Determination of 32 Pesticide Residues in Human Urine by Amino Multi-Walled Carbon Nanotubes-Based Dispersive Solid-Phase Extraction Coupled with Ultra-Performance Liquid Chromatography-Tandem Mass Spectrometry].

OBJECTIVE:An analytical method for the determination of 32 pesticide residues in human urine was established using amino multi-walled carbon nanotubes (NH2-MWCNTs)-based dispersive solid-phase extraction combined with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). METHODS:25% saturated sodium chloride solution was added to precipitate protein in the urine. The pH was adjusted to 5 using 20 mmol/L ammonium acetate solution. The target analytes were adsorbed onto amino multi-walled carbon nanotubes, followed by desorption with acetonitrile. Finally, the extract was analyzed by UPLC-MS/MS. RESULTS:Good linearity for the 32 pesticides was observed within the concentration range of 1-100 μg/L, with correlation coefficients (r) all above 0.999. Fortified at three concentration levels (4, 40, and 200 μg/L, n=6), average recoveries were obtained in the range of 91.2%-110.0%, with relative standard deviations ranging from 1.1%-4.6%. The limits of detection and quantification were determined to be 0.003-0.03 μg/L and 0.01-0.1 μg/L, respectively. The adsorption process of the 32 pesticides onto the NH2-MWCNTs was found to be well described by the pseudo-second-order kinetic model and the Langmuir isotherm model. CONCLUSION:This method is simple and rapid to operate, accurate, and highly sensitive, enabling the rapid detection of 32 pesticide residues in human urine.