A modified QuEChERS method using single-sorbent combined with LC-MS/MS for simultaneous determination of four phenolic pesticide residues in fruits and vegetables

The necessity for matrix-specific optimization of PSA/GCB adsorbent amounts complicates the accurate determination of phenolic pesticides (hexachlorophene, dinoterb, dinosam, dinex) in diverse produce matrices, as required by conventional QuEChERS cleanup to ensure satisfactory recovery and efficiency. To address this limitation, we developed a simplified method employing multi-walled carbon nanotubes (MWCNTs) as a single adsorbent. Although MWCNTs effectively removed chlorophyll and rutin impurities, competitive adsorption toward target analytes was suppressed by incorporating 0.5% (v/v) triethylamine (TEA). This optimized approach ensured efficient matrix cleanup while maintaining analyte integrity. Validated across 15 fruit/vegetable matrices using UPLC-MS/MS, quantification limits (LOQs) ranged from 1.4–2.4 µg/kg. Mean recoveries spanned 77.6%–105.5% with relative standard deviations (RSDs) of 2.9%–12.2%. Compared to traditional QuEChERS, this single-adsorbent formulation strategy offers enhanced simplicity, universality, and matrix robustness for phenolic pesticide monitoring. • Single MWCNT/TEA adsorbent replaces traditional PSA/GCB for universal matrix cleanup. • Competitive adsorption suppressed by 0.5% TEA, ensuring >77% analyte recovery. • Validated across 15 produce matrices (LOQs: 1.4–2.4 µg/kg; RSDs ≤13%). • Simplified workflow enhances robustness for phenolic pesticide monitoring in complex foods.