关键词: 共轭微孔聚合物, 分散固相萃取, 超高效液相色谱-串联质谱, 蜂蜜, 磺胺类药物

Abstract: Residues of sulfonamide antibiotics in honey are recognized as a critical risk factor threatening both product quality and consumer health. The analytical challenge primarily stems from the inherent complexity of the honey matrix, which is characterized by high sugar content and viscosity, causing significant interference during detection. At present, relatively cumbersome pretreatment processes—including liquid-liquid extraction and solid-phase extraction—are mostly adopted to achieve efficient purification and accurate detection of multiple SAs residues in honey. Therefore, the development of a novel sample pretreatment technology capable of specific target enrichment, efficient matrix purification, and simplified operation, integrated with a high-sensitivity detection platform, holds urgent and significant practical value for strengthening antibiotic residue supervision in bee products and promoting the scientific refinement of food safety standards. To address these challenges, this study proposed an innovative approach based on novel adsorbent materials. Two polycyclic aromatic hydrocarbon-based conjugated microporous polymers (designated as TMM-Bp-CMP and Py-Bp-CMP) with distinct pore structures and surface chemical properties were designed and synthesized via precise Sonogashira-Hagihara coupling reactions. These materials were employed for the first time in dispersive solid-phase extraction (DSPE) for the extraction of sulfonamides from honey matrices. Systematic comparative experiments demonstrated that Py-Bp-CMP exhibited superior performance in the recovery of target analytes. To elucidate the theoretical basis for this enhanced performance, density functional theory (DFT) calculations were conducted to simulate the molecular electrostatic potentials of TMM-Bp-CMP, Py-Bp-CMP, and two representative sulfonamides—sulfamonomethoxine (SMM) and sulfamethoxazole (SMZ). The computational results indicated that Py-Bp-CMP, constructed from biphenyl units, possesses a more extensive π-conjugated system and a higher degree of electron delocalization, thereby facilitating stronger π-π stacking interactions with the benzene rings of sulfonamide compounds. This molecular-level insight provides direct theoretical support for the observed adsorption selectivity and offers guidance for the rational design of adsorbent materials. Based on these findings, Py-Bp-CMP was selected as the optimal adsorbent, and its key operational parameters in the DSPE process were systematically optimized via single-factor experiments. Parameters including adsorbent dosage, sample solution pH, ionic strength, elution solvent type, and elution time were thoroughly investigated. The established optimal conditions are as follows: 10 mg of Py-Bp-CMP was used to treat the honey aqueous extract (adjusted to pH 7.0 and containing 50 mg/mL sodium chloride), followed by vortex-assisted adsorption and 2-min elution with acetonitrile. This optimized procedure ensures efficient purification while significantly streamlining operational steps. The refined pretreatment method was successfully coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) to establish an analytical method for the simultaneous determination of multiple sulfonamide residues in honey. Comprehensive method validation confirmed excellent linearity for all target sulfonamides across the range of 0.2-20 ng/mL, with correlation coefficients exceeding 0.99. The LOQs were determined to be 0.9-3.0 µg/kg, demonstrating high sensitivity suitable for trace residue analysis. Recovery studies conducted at three spikied levels yielded average recoveries ranging from 68.7% to 109.8%, with all relative standard deviations (RSDs) below 15%, verifying the method's accuracy and precision. Compared with other pretreatment methods, the approach developed in this study achieves lower detection limits and higher recovery rates while significantly simplifying operational procedures. The extraction process is time-efficient and requires no bulky pretreatment equipment, enabling simultaneous extraction and detection of 16 SAs in honey. It demonstrates outstanding performance across multiple dimensions, including sensitivity, applicability, and accuracy. In conclusion, this study successfully developed an integrated analytical strategy combining novel functionalized adsorbent materials, efficient sample pretreatment, and a high-sensitivity detection platform. The present work not only provides a reliable and practical technical tool for quality monitoring and risk assessment of bee products but also, through the exploration of Py-Bp-CMP's design concept and adsorption mechanisms, offers valuable direction for the development of highly selective adsorbent materials targeting trace organic pollutants in other complex matrices. Future research should focus on extending the applicability of this material and methodology to other challenging food systems (e.g., meat and dairy products) and evaluating its broader utility, which will contribute to updating relevant detection standards and advancing green and efficient analytical technologies.

Key words: conjugated microporous polymers (CMP), dispersive solid-phase extraction (DSPE), ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), honey, sulfonamide antibiotics (SAs)