原位合成铜基金属有机框架差分脉冲伏安法快速检测肉制品中亚硝酸盐

为构建肉制品中亚硝酸盐的快速检测方法，本实验采用电化学法在玻碳电极（glassy carbon electrode，GCE）表面原位合成铜基金属有机框架（Cu-based metal organic frameworks，Cu-MOFs），制备亚硝酸盐电化学传感器。合成的Cu-MOFs在电极表面均匀分布，利用扫描电镜可以看到单个Cu-MOFs颗粒呈八面体形状。NO2－在电位作用时失去电子以发生氧化反应，依据电子转移产生的电流信号，可实现NO2－的定量检测。电极表面修饰的Cu-MOFs能够催化NO2－的氧化反应，可有效增强电极的响应信号，有利于提高NO2－检测的灵敏度。使用Cu-MOFs/GCE结合差分脉冲伏安法对NO2－进行测定，NO2－的氧化峰电流与其浓度在10～1?200?μmol/L范围具有良好的线性关系，检测限为1.57?μmol/L，并且该传感器具有良好的选择性和稳定性。利用Cu-MOFs/GCE测定市售肉制品中亚硝酸盐含量，结果显示该传感器获得的检测结果与盐酸萘乙二胺法的结果基本一致，证明该电极可以用于食品亚硝酸盐的检测。

Rapid Detection of Nitrite in Meat Products by in-Situ Synthesized Cu-Based Metal Organic Frameworks Coupled with Differential Pulse Voltammetry

In order to develop a method for rapid determination of nitrite in meat products, Cu-based metal organic frameworks (Cu-MOFs) were synthesized electrochemically, which were found to be uniformly distributed on the surface of a glassy carbon electrode (GCE). The scanning electron microscopic (SEM) images exhibited that Cu-MOF particles were octahedral. NO2- lost an electron to become oxidized. According to the current signal produced by electron transfer, NO2- could be quantitatively detected. The modified Cu-MOFs could catalyze the oxidation of NO2-, thereby contributing to increased response signal from the working electrode and improving the sensitivity of NO2- detection. NO2- concentration was measured by differential pulse voltammetry using Cu-MOFs/GCE. The peak current increased linearly with the NO2- concentration in the range of 10–1 200 μmol/L. The limit of detection was 1.57 μmol/L. Besides, the prepared electrochemical sensor exhibited good selectivity and stability. The results of the sensor for the nitrite content in meat products were in good agreement with those obtained by the naphthyl ethylenediamine dihydrochloride spectrophotometric method, indicating that the electrode has great potential in the analysis of nitrite in food samples.