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    碳量子点/金属有机骨架材料修饰玻碳电极用于双酚A的电化学检测

    Carbon Quantum Dots/Metal-Organic Framework Material Modified Electrode for Electrochemical Detection of Bisphenol A

    • 摘要: 制备了粒径约3 nm的聚二甲基二烯丙基氯化铵(PDDA)修饰的碳量子点(CDs),通过静电吸附作用将其负载在具有木柴状纳米棒结构的铈-金属有机骨架材料(Ce-MOFs)上制备碳量子点/金属有机骨架复合材料(PDDA-CDs/Ce-MOFs),并滴涂在玻碳电极(GCE)上制备修饰电极,用于富集牛奶中的双酚A(BPA),富集电压为0.3 V,富集时间为150 s。修饰电极上富集的BPA含量用差示脉冲伏安法测定。结果表明,BPA在修饰电极表面产生的氧化响应电流约为在GCE上的25倍,此氧化过程是一个吸附控制的两个电子和两个质子参与转移的过程;BPA的浓度与其对应的氧化峰电流分别在0.01~5.0 μmol·L-1和5.0~50 μmol·L-1内呈线性关系,检出限(3S/N)为2.2 nmol·L-1。对5.0 μmol·L-1 BPA标准溶液平行测定6次,所得测定值的相对标准偏差(RSD,n=6)为4.6%;修饰电极在保存7 d后和28 d后,对BPA的氧化响应电流分别降为初始电流的96.8%和95.4%,表明修饰电极具有良好的重复性和稳定性。用此方法分析了6种牛奶样品,均未检出BPA。对这6种样品进行加标回收试验,回收率为97.4%~105%,测定值的RSD(n=5)为2.1%~4.2%。

       

      Abstract: CDs modified by PDDA with particle size of about 3 nm were prepared, and then loaded on Ce-MOFs with firewood like nanorod structure by electrostatic adsorption, to prepared the composite material (PDDA-CDs/Ce-MOFs). The modified electrode prepared by dropping the composite material on the surface of GCE was used for the enrichment of BPA in milk, with enrichment voltage of 0.3 V and enrichment time of 150 s, and the concentration of BPA enriched on modified electrode was determined by differential pulse voltammetry. Results showed that the oxidation response current of BPA on the modified electrode was about 25 times than that of GCE, and the oxidation process was a process controlled by adsorption with two electrons and two protons to participate in the tranfer; linearity relationship between the concentration of BPA and its respective oxidation peak current was kept in the ranges of 0.01-5.0 μmol·L-1 and 5.0-50 μmol·L-1, with detection limit (3S/N) of 2.2 nmol·L-1. 5.0 μmol·L-1 BPA standard solution was determined for 6 times in parallel, giving RSDs (n=6) of 4.6%. After the modified electrode was storaged for 7 d and 28 d, the oxidation peak current of BPA decreased to 96.8% and 95.4% of the initial current, respectively. It was found that the modified electrode has good repeatability and stability. The proposed method was used for the determination of 6 milk samples, and no BPA was detected. A spiked recovery test was made on 6 samples, giving recoveries of BPA in the range of 97.4%-105%, and RSDs (n=5) of the determined values were found in the range of 2.1%-4.2%.

       

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