Sulfonic Acid-Functionalized Ordered Mesoporous Silica as a Dispersive Solid-Phase Extraction Adsorbent for the Determination of 30 Organophosphorus Pesticides

Abstract

Organophosphorus pesticides (OPPs) have been widely used in agricultural production due to their high efficacy and broad-spectrum activity. However, their residues pose a significant threat to human health, necessitating the development of efficient and sensitive detection methods. Dispersive solid-phase extraction (DSPE) is a high-performance sample pretreatment technique whose performance highly depends on the properties of the adsorbent. This study synthesized a sulfonic acidfunctionalized ordered mesoporous silica material (SBA-15-SO 3 H) and systematically evaluated its performance as a DSPE adsorbent for the simultaneous enrichment and determination of 30 OPPs in complex food matrices. The material was characterized by SEM, TEM, XRD, FT-IR, SAXS, and nitrogen adsorption-desorption isotherms, confirming the successful grafting of sulfonic acid groups and the preservation of the ordered mesoporous structure. DSPE conditions, including adsorbent amount, adsorption time, and elution solvent type and time, were systematically optimized.Under optimal conditions, coupled with LC-MS/MS analysis, the method showed good linearity in the range of 1-100 µg/kg (R 2 ≥0.9900). The limits of detection (LODs) and quantification (LOQs) for the 30 OPPs in five food matrices (apple juice, grape juice, strawberry, onion, cabbage) were 0.04-0.39 µg/kg and 0.13-1.29 µg/kg, respectively. The average recoveries at three spiked levels (5, 10, and 20 µg/kg) ranged from 72.81% to 104.96%, with relative standard deviations (RSDs) of 3.03%-9.50%. Analysis of real samples demonstrated that this method is suitable for the high-throughput and highly sensitive detection of multiple OPP residues in various foods, with all detected pesticide levels below the maximum residue limits specified by the Chinese national standard (GB 2763-2021). This study indicates that SBA-15-SO 3 H is an efficient and practical DSPE adsorbent with promising application potential in the multi-residue analysis of pesticides in complex food matrices.