超高纯单壁碳纳米管氧化铜修饰电极灵敏测定壬基酚

Sensitive determination of nonylphenol by ultra-high purity single wall carbon nanotube/copper oxide modified electrode

基于超高纯单壁碳纳米管(uhp-SWCNTs)的大比表面积和高导电性及氧化铜(CuO)的良好电催化活性,构建了一种用于快速、灵敏测定壬基酚的电化学传感器。通过扫描电镜(SEM)表征了合成的CuO的表面形貌,发现CuO呈花状形貌,表面存在大量的孔隙。采用循环伏安法(CV)和差分脉冲伏安法(DPV)研究了传感器的电化学性能。同时考察了pH值、CuO和uhp-SWCNTs的修饰量、富集电位、富集时间及搅拌速度等实验参数对传感器响应的影响。结果表明,CuO和uhp-SWCNTs具有良好的协同作用,其修饰电极对壬基酚的催化效果优于单独的CuO或uhp-SWCNT修饰电极。壬基酚在修饰电极上的电化学氧化反应是一个单质子、单电子的反应,同时是一个不可逆的吸附控制电极过程。壬基酚的氧化峰电流与其浓度在0.025~3.2μmol·L^(-1)范围内呈良好的线性关系,检出限(S/N=3)为1.8 nmol·L^(-1)。该传感器具有良好的选择性、重现性和稳定性,应用于测定水样和土壤中壬基酚,加标回收率为85.2~102%。

An electrochemical sensor for the rapid and sensitive determination of nonylphenol was constructed based on the large specific surface area and high sensitivity of ultra-high pure single-walled carbon nanotubes(uhp-SWCNTs),as well as excellent electrocatalytic activity of copper oxide(CuO).The surface morphology of the synthesized CuO was characterized by scanning electron microscopy(SEM).It was found that the CuO presented a flower-like morphology with a large number of interspaces on its surface.The electrochemical performance of the sensor was investigated by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).The experimental parameters influencing the response of the sensor,such as pH value,modification amount of CuO and uhp-SWCNTs,accumulation potential,accumulation time and stirring speed were also investigated.The results showed that CuO and uhp-SWCNTs had a good synergistic effect,and the modified electrode exhibited better catalytic effect on nonylphenol than the single CuO or uhp-SWCNTs modified electrode.The electrochemical oxidation of nonylphenol on the modified electrode was a one-proton and one-electron reaction,and an irreversible adsorption-controlled electrode process.The oxidation peak current of nonylphenol was linear to its concentration in the range of 0.025~3.2μmol·L^(-1),and the detection limit(S/N=3)was 1.8 nmol·L^(-1).The proposed sensor showed good selectivity,reproducibility and stability,and was applied to the determination of nonylphenol in water and soil samples with recoveries ranging from 85.2 to 102%.