Deep eutectic solvent-modified multi-walled carbon nanotubes as QuEChERS adsorbents coupled with gas chromatography-mass spectrometry for the determination of pesticide residues in Lycium barbarum

Abstract

The objective of this study was to establish a methodology for determining the residue concentrations of 13 pesticides in Lycium barbarum extract. To eliminate interfering substances in the matrix, deep eutectic solvent-functionalized Multi-Walled Carbon Nanotube (DES@MWCNT) was prepared. DES@MWCNT was firstly introduced as the sole purification agents, replacing PSA and C18 in QuEChERS extraction. Pesticide analysis was achieved using the quick, easy, cheap, effective, rugged, safe (QuEChERS) method in combination with gas chromatography-mass spectrometry (GC-MS) analysis. Unlike traditional QuEChERS, this method employs only a single adsorbent, DES@MWCNT, to replace the combined effect of multiple adsorbents, thereby enhancing the simplicity and generality of the method. Results indicated that DES-5@MWCNT effectively functioned as QuEChERS clean-up materials, significantly reducing the matrix effect to the range of −9.27–12.59 % after cleanup treatment. The concentrations and peak areas of pesticides exhibited strong linearity, with a correlation coefficient (R²) of ≥ 0.99. The limits of detection (LOD) and quantification (LOQ) ranged from 0.87 to 11.05 μg/kg and 2.89–36.83 μg/kg, respectively. Accuracy was between 79.3 % and 105.6 %, with relative standard deviations (RSDs) ranging from 2.6 % to 17.9 %. The DES@MWCNT-based QuEChERS treatment is expected to have broad practical applicability for other pesticide targets and various sample matrices.