Wang Po, Mai Zhibin, Dai Zong, Li Yongxin, Zou Xiaoyong
School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
Biosens Bioelectron. 2009 Jul 15;24(11):3242-7. doi: 10.1016/j.bios.2009.04.006. Epub 2009 Apr 16.
A promising electrochemical sensor for sensitive determination of nitrite was fabricated by construction of Au nanoparticles on the surface of choline chloride (Ch) modified glassy carbon electrode (GCE). Field emission scanning electron microscope, powder X-ray diffraction, X-ray photoelectron spectroscopy and electrochemical techniques were used for the surface characterization of the modified electrode. It was demonstrated that Ch was covalently immobilized onto the GCE surface forming a planted Ch monolayer, which could provide a suitable supporting material for the construction of Au nanoparticles. As a result, the Au nanoparticles with average size of about 110 nm were assembled to form a flowerlike structure on the surface of Ch monolayer. Moreover, the uniform nano-Au/Ch film exhibited remarkable electrocatalytic activity towards the oxidation of nitrite with obvious reduction of overpotential. Under the optimum conditions, the linear range for the detection of nitrite was 4.0 x 10(-7) to 7.5 x 10(-4)M with a high sensitivity of 0.354 microA microM(-1), and a low detection limit of 1.0 x 10(-7)M. The proposed method was successfully applied in the detection of nitrite in water samples and sausage samples, and the results were consistent with those obtained by ion chromatography and UV-visible spectrophotometric methods.
通过在氯化胆碱（Ch）修饰的玻碳电极（GCE）表面构建金纳米颗粒，制备了一种用于灵敏测定亚硝酸盐的电化学传感器。利用场发射扫描电子显微镜、粉末X射线衍射、X射线光电子能谱和电化学技术对修饰电极进行表面表征。结果表明，Ch共价固定在GCE表面形成了一个接枝的Ch单分子层，可为金纳米颗粒的构建提供合适的支撑材料。结果，平均尺寸约为110nm的金纳米颗粒组装在Ch单分子层表面形成了花状结构。此外，均匀的纳米金/Ch膜对亚硝酸盐的氧化表现出显著的电催化活性，过电位明显降低。在最佳条件下，亚硝酸盐检测的线性范围为4.0×10（-7）至7.5×10（-4）M，灵敏度高达0.354μAμM（-1），检测限低至1.0×10（-7）M。该方法成功应用于水样和香肠样品中亚硝酸盐的检测，结果与离子色谱法和紫外可见分光光度法一致。
