自组装纳米金修饰玻碳电极检测亚硝酸根

Self-Assembled Gold Nanoparticles Modified Electrode for Electrochemical Detection Nitrite

将N-[3-(三甲氧硅基)丙基]-乙二胺与金溶胶通过自组装制备亚硝酸根的电化学传感器.原子力显微镜图(AFM)显示纳米金自组装在氨基硅烷修饰的玻碳电极表面.由于质子化的氨基硅烷与带负电的亚硝酸根间的相互作用以及纳米金对亚硝酸根具有较好的催化作用,亚硝酸根在该修饰电极上的氧化电位与在玻碳电极上的氧化电位相比负移了140 mV.利用微分脉冲伏安法和微分脉冲安培法研究了亚硝酸根电流响应信号与浓度间的关系.在最优实验条件下,亚硝酸根的氧化峰电流与其浓度在5.0×10-7～1.0×10-3mol.L-1的浓度范围内呈良好的线性关系,检测限可达到2.0×10-7mol.L-1(信噪比为3).用分光光度法及本研究提出的方法对实际样品中亚硝酸根的测定进行了比较,测定结果的差异很小.本研究所提出的测定亚硝酸根的方法具有较高的灵敏度和较好的重现性.

A modified sensor was fabricated by N-[3-（trimethoxysilyl）propyl]-ethylene diamine（TSPED） and colloidal gold particles（AuNPs） on glass carbon electrode（GCE）.Atomic force microscopy（AFM） demonstrated that the colloidal gold particles were self-assembled onto the amine groups of the sol-gel.Due to the excellent electrocatalytic activity of gold nanoparticles toward the oxidation of nitrite and the interaction between the protonated TSPED film and the negatively-charged nitrite,the operating potential for nitrite oxidation was shifted about 140mV to negative side,compared to bare GCE.The differential pulse voltammetry and the differential pulse amperometry were employed in the process of electrochemical measurements.Under the optimal conditions,a highly linear response to nitrite in the concentration range of 5.0 × 10-7-1.0 × 10-3 mol.L-1 was observed,with a detection limit of 2.0 × 10-7 mol.L-1（S /N = 3）.The real water samples were investigated and the results were in good agreement with those obtained by standard spectrophotometric method.This method proposed by this paper possesses high sensitivity and good reproducibility.