Preparation Of Nano-materials And Electrochemical Detection For Nitrate

Nanomaterials are the core of nanoscience and nanotechnology. The unique properties of nanoscale materials offer excellent prospects for interfacing biological recognition events with electronic signal transduction and for designing a new generation of bioelectronic devices exhibiting novel functions. If modified on the surface of the electrodes or added to the electrodes as raw materials, it could contribute to the fabrication of electrochemical sensors, which could greatly improve the performance of the electrodes. It exhibits better sensitivity, faster response, inexpensive and easy to operate. Thus, the main research work and experiments are listed as follows:1. Functional nanomaterials including magnetic malachite green molecular imprinting polymer nanospheres and rare earth europium complex doped fluorescent nanospheres were successfully prepared here. Before the research of magnetic malachite green molecular imprinting polymer nanospheres, malachite green molecular imprinting polymer nanospheres were synthesized by microemusion polymerization method. The results of the adsorption experiments proved good adsorption and can separate the malachite green from the solution quickly. On the basis of the synthesis of malachite green molecular imprinting polymer nanospheres, silica nanospheres of different sizes of40nm,70nm and100nm were synthesized also by microemusion polymerization method. When modified with amino, the nanoparticles could react with ninhydrin, with an absorption peak at570nm observed by the ultraviolet absorption method. Europium complex doped fluorescent nanospheres were prepared for labeling the biological antibody or antigen, combined with time-resolved fluorescence techniques to achieve the detection of biological samples.2. A simple and fast electroanalytical method for the detection of nitrate at an in-situ copper modified glassy carbon electrode (GCE) in an acidic media is proposed on the basis of in-situ square wave voltammetry (SWV). Compared with K2SO4, the cooper modified electrode showed higher peak current produced at about-0.55V when placing the GCE in the solution containing KCl. Through a series of optimization experiments, the results predicts that the copper modified electrode will perform best when the pH value of the supporting solution is1, the concentration of Clis1mM, the concentration of Cu2+is5mM and the optimum time for deposition of copper film is400s. Under the optimum condition, the relationship between the peak current and the ion concentration was studied. The peak current increases with the increase of the concentration of nitrate, with the linear regression equation1(μA)=3.8232+0.0833C (μg/L), and a very good linear correlation (R=0.9996) can be observed. The limit of detection (LOD) calculated from the parameters obtained from the analytical curve, using LOD=3Sb/s, reached10μM. When applying this method to detect nitrate in real water samples, the results exhibit good sensitivity. Moreover, this paper synthesized cooper oxide and manganese oxide nanoparticles. Then fabricated copper oxide nanoparticles doped ionic liquid carbon paste electrodes. However, when compared with the glassy carbon electrodes and ionic liquid carbon paste electrodes, this kind of electrodes showed wider peak-to-peak separation and lower peak current, so it needs further investigation.Through the research of the technology of the fabrication of nanomaterials and the electrochemical sensors for the detection of nitrate, it is more mature for preparation of the nanomaterials in the lab. Moreover, a simple and fast electroanalytical method for the detection of nitrate is proposed, which makes the wide application of nanomaterials to the field of electrochemistry possible.