纳米TiO2/还原石墨烯复合修饰电极用于食品中 柠檬黄的检测

为了检测食品中柠檬黄的含量,利用滴涂法和电化学还原法制备纳米TiO_2/还原石墨烯复合修饰玻碳电极(TiO_2-Er GO/GCE)。采用透射电子显微镜和X射线粉末衍射仪对TiO_2和TiO_2-GO两种修饰电极材料进行表征;通过循环伏安法观察了柠檬黄在不同电极上的电化学行为,并对检测条件如p H值、富集电位、富集时间进行了优化。实验结果表明:TiO_2-Er GO/GCE增大了电极的电化学活性面积,提高了柠檬黄的电化学氧化响应;最优的检测条件为p H值为3.7、富集电位为-0.20 V、富集时间为180 s;在最优的检测条件下,采用线性扫描伏安法检测柠檬黄的线性范围为2.0×10-8~2.0×10-5 mol/L,检测限为8.0×10-9 mol/L(信噪比为3)。

Detection of Tartrazine Based on TiO2/Electrochemically Reduced Graphene Composites Modified Electrode

TiO2/electrochemically reduced graphene composite modified glassy carbon electrode (TiO2-ErGO/GCE) for the purpose of sensitive detection of Tartrazine was prepared by dropping-casting followed by an electrochemical reduction method. The prepared material was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Cyclic voltammetry and second-order derivative linear scan voltammetry were performed for analyzing the electrochemical sensing of tartrazine on different electrodes. The determination conditions (including pH value, accumulation potential as well as time) were optimized systematically. The results showed that the TiO2-ErGO composites increased the electrochemical active area and enhanced the electrochemical responses of tartrazine significantly. The optimal pH was 3.7. The optimal accumulation potential and time were -0.2 V and 180 s respectively. Under the optimum detection conditions, the peak current was found to be linear with tartrazine concentration in the range of 2.0×10-8~2.0×10-5 mol/L with a lower detection limit of 8.0×10-9 mol/L (S/N:3). The proposed TiO2-ErGO/GCEs have been successfully applied in the detection of tartrazine in soft drink samples with satisfactory results.