基于金纳米粒子修饰石墨烯碳糊电极的同型半胱氨酸电化学传感

Electrochemical Sensing of Homocysteine Based on Gold Nanoparticles Modified Graphene Carbon Paste Electrode

本文基于金纳米粒子修饰石墨烯碳糊电极,构建了同型半胱氨酸的电化学传感器。电化学技术表征表明,在中性电解质溶液中,金纳米粒子-石墨烯复合膜对同型半胱氨酸的电化学氧化具有明显的催化作用。电化学扫描电子显微镜技术表征表明,在金纳米粒子-石墨烯复合膜电极表面上,可以观察到大量的金纳米粒子颗粒,整个电极表面呈现疏松多孔的结构,这种结构有利于将同型半胱氨酸富集到电极表面,从而有效提高传感器的灵敏度;金纳米粒子和石墨烯的良好导电性则有利于加快同型半胱氨酸与电极之间的电子传递,从而缩短传感器的响应时间。在最佳检测条件下,同型半胱氨酸在传感器上的氧化峰电流与其浓度在3.0~100μmol/L浓度范围内呈线性增加,灵敏度为1.22 nA/(μmol/L),检出限为0.8μmol/L,响应时间为3 s。此外,利用标准加入法测得该传感器测定同型半胱氨酸的平均回收率为97.2%,证明方法具有较好的准确度。

In this work,the electrochemical sensor of homocysteine was constructed based on the gold nanoparticles modified graphene carbon paste electrode.Electrochemical characterization shows that gold nanoparticles-graphene nanocomposite has obvious electrocatalytic effect to the oxidation of homocysteine in neutral electrolyte solution.Characterization from scanning electron microscope shows that a large amount of gold nanoparticles can be observed on the modified electrode surface that presents a loose and porous structure,which is beneficial for the enrichment of homocysteine and ensuring the sensitivity of the sensor.The good conductivity of gold nanoparticles and graphene can accelerate the electron transfer between homocysteine and the electrode,which is important for shortening the response time of the sensor.Under the optimal detection conditions,the oxidation peak current of homocysteine on the sensor increases linearly with its concentration in the range of 3.0-100 μmol/L,the sensitivity is 1.22 nA/(μmol/L),the detection limit is 0.8 μmol/L and the response time is 3 s.In addition,the average recovery measured through standard addition method was 97.2%,indicating that the method has good accuracy.