MOFs衍生的Fe-N-C纳米酶用于对苯二酚的比色检测

MOFs-derived Fe-N-C nanozyme for colorimetric detection of hdroquinone

【目的】建立一种方便的检测对苯二酚(hydroquinone,HQ)的方法。【方法】采用化学掺杂法合成Fe-ZIF-8前驱体,对前驱体热解处理,得到Fe-N-C纳米酶粉末;通过活性对比、自由基捕获和动力学实验,系统探究Fe-N-C的类酶活性;依据HQ具有还原性强、可将3,3',5,5'-四甲基联苯胺(TMB)显色体系还原为无色状态的特性,构建比色法检测HQ的传感平台。【结果】Fe-N-C表现出优异的过氧化物酶样活性,可以快速将显色底物TMB催化氧化为蓝色;Fe-N_(x)是Fe-N-C主要的活性位点,羟基自由基(•OH)、超氧自由基(O_(2)^(•−))和单线态氧(^(1)O_(2))是起主要作用的活性氧;Fe-N-C纳米酶对TMB的亲和力优于天然辣根过氧化物酶,该方法检测HQ的线性范围为0~33μmol/L,检测限为0.356μmol/L,同时具有良好的抗干扰能力。【结论】构建一种用于环境分析的金属有机骨架化合物(metal organic framework,MOFs)衍生物纳米酶,可实现HQ的简单和灵敏检测。

Objective Hydroquinone is a phenolic compound widely used in industry.It is difficult to degrade in the aquatic ecological environment and is harmful to human health.Therefore,constructing a simple and sensitive method for the detection of hydroquinone is of great significant.Methods In this study,an MOFs-derived Fe-N-C catalyst was synthesized through a simple chemical doping method and hightemperature pyrolysis,using an Fe-ZIF-8 precursor.The physicochemical properties of Fe-N-C were characterized in detail through SEM,TEM,XRD,FTIR,and XPS.The effect of the introducing Fe3+on the enzyme activity of the catalyst was studied.The enzyme-like activity,catalytic mechanism,and kinetic parameters of Fe-N-C were systematically investigated.Based on the enzyme-like activity of Fe-N-C,a colorimetric sensor for the detection of hydroquinone was developed.Results and Discussion Based on the aforementioned characterization and experimental findings,Fe-N-C exhibited excellent peroxidase-like activity and weak oxidase-like activity.In addition,in the presence of hydrogen peroxide,OPD and ABTS as substrates were also oxidized to yellow and blue products by Fe-N-C,with characteristic absorption peaks at 448 nm and 416 nm,respectively.Additionally,the poisoning experiment with KSCN showed that Fe-Nx was the main active site in Fe-N-C catalyst.The study of the catalytic mechanism confirmed that·OH,O_(2)^(•−)and^(1)O_(2)were active oxygen radicals playing a major role in the catalytic oxidation of TMB.The catalytic activity of Fe-N-C nanozymes was further studied through steady-state kinetic analysis.The Km and Vmax of Fe-N-C for TMB were 0.134 mmol/L and 0.754×10^(-7)M·s^(-1),respectively,while those for H_(2)O_(2) were 16.535 mmol/L and 2.533×10^(-7)M·s^(-1),respectively.Finally,the colorimetric sensor detected HQ in a linear range of 0~33μmol/L with a detection limit of 0.356μmol/L.Through anti-interference experiments,the established colorimetric sensing platform showed robust anti-interference ability and selectivity in detecting hydroquinone.Conclusion The introduction of Fe^(3+)significantly improves the enzyme-like activity of N-C nanomaterials.Fe-N-C exhibits excellent peroxidase-like activity,which can rapidly oxidize the chromogenic substrate 3,3',5,5'-tetramethylbenzidine(TMB)to blue.Fe-Nx is the main active site of Fe-N-C nanozymes,and hydroxyl radica(^(l)•OH),superoxide radicals(O_(2)•^(−))and singlet oxygen(^(1)O_(2))are the main reactive oxygen species(ROS).Hydroquinone is a strong reducing organic pollutant that can reduce blue oxTMB to a colorless state.Based on this,a sensing platform for colorimetric detection of HQ was constructed.This method has good sensitivity and selectivity for hydroquinone,which expands the application of MOFs-based nanozymes in the field of environmental pollutant detection.