Core-shell structured magnetic covalent organic frameworks (Fe₃O₄@COFs) were synthesized via a facile approach at room temperature using 1,3,5-tris(4-aminophenyl)benzene (TAPB) and 2,5-dibromo-1,4-benzenedicarboxaldehyde (DBDA) as two building blocks for the first time. The Fe₃O₄@COFs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), nitrogen adsorption-desorption isotherms, and zeta potentiometric analysis. The Fe₃O₄@COFs had a high specific surface area (141.94 m²·g⁻¹) and uniform pore size distribution (average 4.53 nm). They also demonstrated good magnetic response (32.49 emu·g⁻¹) and good thermal and chemical stabilities. Furthermore, adsorption experiments were conducted to evaluate the adsorption capacities and adsorption times of Fe₃O₄@COFs to diphenylamine (DPA) and its analogs, including benzidine (BZ), 1-naphthylamine (1-NA), 4-phenylphenol (4-PP), and O-tolidine (O-TD). From the experimental results, the maximum adsorption capacities of DPA, 1-NA, 4-PP, BZ, and O-TD were calculated as 246.25, 95.20, 85.85, 107.20, and 123.55 mg·g⁻¹, respectively. A duration of 20 min was sufficient for adsorption. The Fe₃O₄@COFs were explored as adsorbents for magnetic solid-phase extraction (MSPE) of DPA and its analogs, and the MSPE parameters, including adsorbent dosage, extraction time, pH, ionic strength, desorption solvent, desorption time, and desorption frequency were optimized. Combined with HPLC using diode-array detection, a simple, fast, and sensitive method was proposed to detect DPA and its analogs, which exhibited good linearity (r >0.9946) in the range of 0.1–100 μg·mL^–1. Moreover, the low limits of detection (ranging from 0.02 to 0.08 μg·mL^–1, S/N = 3), low limits of quantitation (ranging from 0.05 to 0.30 μg·mL^–1, S/N = 10), good precision with low relative SDs (<5.86% for intra-day and <6.44% for inter-day) were obtained. Finally, Fe₃O₄@COFs were applied to the effective MSPE of DPA and its analogs in actual samples chosen from the natural environment, and good recoveries (ranging from 79.97 to 122.52%) were observed.

使用1,3,5-三（4-氨基苯基）苯（TAPB）和2,5-二溴-1在室温下通过简便方法合成核-壳结构磁性共价有机骨架（Fe ₃ O ₄ @COFs） ，4-苯二甲醛（DBDA）首次作为两个组成部分。通过扫描电子显微镜（SEM），透射电子显微镜（TEM），傅立叶变换红外（FT-IR）光谱，粉末X射线衍射（XRD），X射线光电子能谱（Fe）对Fe ₃ O ₄ @COF进行了表征。 XPS），热重分析（TGA），振动样品磁力分析（VSM），氮吸附-解吸等温线和zeta电位分析。铁₃ O ₄@COF具有高的比表面积（141.94 m ² · g ^-1）和均匀的孔径分布（平均4.53 nm）。他们还表现出良好的磁响应（32.49 emu · g ^-1）和良好的热稳定性和化学稳定性。此外，进行吸附实验以评估Fe ₃ O ₄ @COFs对联苯胺（BZ），1-萘胺（1-NA），4-苯基苯酚（4）的二苯胺（DPA）及其类似物的吸附能力和吸附时间。-PP）和邻甲苯胺（O-TD）。根据实验结果，DPA，1-NA，4-PP，BZ和O-TD的最大吸附容量计算为246.25、95.20、85.85、107.20和123.55 mg · g ^-1， 分别。20分钟的持续时间足以吸附。研究了Fe ₃ O ₄ @COFs作为DPA及其类似物的磁性固相萃取（MSPE）的吸附剂，以及MSPE参数，包括吸附剂用量，萃取时间，pH，离子强度，解吸溶剂，解吸时间和优化解吸频率。结合使用二极管阵列检测的HPLC，提出了一种简单，快速且灵敏的方法来检测DPA及其类似物，该方法在0.1–100μg · mL ^–1的范围内表现出良好的线性（r > 0.9946）。此外，检测下限（范围为0.02至0.08μg · mL ^–1，S / N = 3），定量限低（范围从0.05到0.30μg · mL ^–1，S / N  = 10），精密度好，相对SD低（日间<5.86％，日间<6.44％）获得了。最后，将Fe ₃ O ₄ @COFs应用于从自然环境中选择的实际样品中的DPA及其类似物的有效MSPE，并观察到良好的回收率（从79.97％到122.52％）。