磁性金属有机骨架-聚多巴胺的制备并用于水产养殖水样中阳离子染料的萃取检测

利用多巴胺（DA）中的儿茶酚基团能与金属有机骨架晶体（MOFs）中金属离子螯合的原理，以ZIF-67为模板，经DA蚀刻-自聚合形成具有孔洞结构的聚多巴胺（PDA）壳层，制备了磁性-MOFs-PDA（Fe₃O₄@Z67D）新型材料。多种表征手段验证了材料的形貌、结构和性能。新型材料具有亲水性的表面、纳米级的孔径，以及良好的磁响应，被用作磁固相萃取吸附剂。结合高效液相色谱分析手段，建立了萃取检测亚甲蓝（MB）和结晶紫（CV）两种阳离子染料的新方法。在最优的萃取和色谱分析条件下，MB和CV的线性范围分别为0.5~200 μg/L和0.01~50 μg/L，检出限分别为0.04 μg/L和0.008 μg/L，对两种染料的富集因子分别为777和688。新型材料重复使用10次，其萃取性能未见发生变化。该方法成功应用于检测淡水鱼养殖用水中痕量的MB和CV，加标回收率为82.0%~109.0%，RSD低于2.9%。

Preparation of magnetic metal-organic frameworks-polydopamine for extraction and detection of cationic dyes from water samples in a fishery

The catechol group of dopamine (DA) can chelate with the metal ion in the crystal of molecular organic frameworks (MOFs). Based on this principle, a magnetic metal polydopamine (PDA) framework (Fe₃O₄@Z67D) was prepared using ZIF-67 as the template, which was etched by DA, followed by polymerization of the DA monomers to form a PDA coating with a porous structure. The morphology, structure, and properties of the material were determined by various characterization methods. Fe₃O₄@Z67D was used as an adsorbent, and a magnetic solid-phase extraction/high-performance liquid chromatography method for the determination of two cationic dyes, methylene blue (MB) and crystal violet (CV), was established. Under the optimized extraction and detection conditions, the linear ranges for MB and CV were 0.5-200 μg/L and 0.01-50 μg/L, respectively, and the corresponding detection limits were 0.04 μg/L and 0.008 μg/L. The experimental results showed that the enrichment factors of Fe₃O₄@Z67D for the two dyes were 777 and 688, respectively. The extraction performance was largely unaffected even after the new material was reused 10 times. The method was applied successfully for the adsorption and detection of the above mentioned two dyes in fishpond water. The spiking recoveries of the two cationic dyes ranged from 82.0% to 109.0%, and the RSD was lower than 2.9%.