Simultaneous determination of 114 pesticide residues in tobacco by LC-MS/MS using multi-walled carbon nanotubes-based dispersive solid phase extraction
A method capable of simultaneously determining the residues of 114 pesticides in tobacco was developed by dispersive solid phase extraction (DSPE), where multi-walled carbon nanotubes (MWCNTs) were used as extraction material, and LC-MS/MS in multiple reaction monitoring (MRM) mode. With its unique middle-hollow structure and huge specific surface area, MWCNT exhibited excellent adsorption ability in pre-treating tobacco samples for pesticide residue detection. The type and addition rate of MWCNT were optimised in experiments, and the purification of the sample was enhanced on the basis of the QuEChERS method. The residues of 114 pesticides in tobacco were determined by LC-MS/MS after the preparation of samples with the method mentioned above. Matrix matched calibration was used for quantification, the calibration curve presented good linearity (r2>0.999) and the mean recoveries of three spiking levels (0.02~0.2 mg/kg) ranged from 69% to 119% with the relative standard deviations of 1 to 19%. The limits of quantitation (LOQs) were in the range of 0.2-40 µg/kg. The developed method has shown its advantages in high throughput, sensitivity, accuracy, low cost and convenience in sample treatment.