Sulfonic acid-functionalized ordered mesoporous silica as a dispersive solid-phase extraction adsorbent for the determination of 30 organophosphorus pesticides

Abstract

Organophosphorus pesticides (OPPs) are widely used in agriculture for their high efficacy and broad-spectrum activity, but their residues pose severe threats to human health, necessitating efficient and sensitive detection methods. Dispersive solid-phase extraction (DSPE) is a high-performance sample pretreatment technique whose performance is critically determined by adsorbent properties. This study synthesized sulfonic acid-functionalized ordered mesoporous silica (SBA-15-SO₃H) and evaluated its performance as a DSPE adsorbent for simultaneous enrichment and determination of 30 OPPs in complex food matrices. Multiple characterizations (SEM, TEM, XRD, FT-IR, SAXS, nitrogen adsorption–desorption) confirmed successful sulfonic acid grafting and retention of the ordered mesoporous structure. DSPE parameters including adsorbent dosage, adsorption time, and elution conditions were systematically optimized. Coupled with LC-MS/MS, the method exhibited good linearity (1–100 μg kg⁻¹, R² ≥ 0.9900). The LODs and LOQs in five food matrices were 0.04–0.39 μg kg⁻¹ and 0.13–1.29 μg kg⁻¹, respectively. Average recoveries at three spiked levels ranged from 72.81% to 104.96% with RSDs of 3.03%–9.50%. Real sample analysis verified its suitability for high-throughput detection of multi-OPP residues, with all detected levels below GB 2763-2021 limits. SBA-15-SO₃H shows promising application potential in pesticide multi-residue analysis.