| Nanotechnology is recognized as the most promising scientific research domain in the 21st century. The nanomaterials fundamentally changed the material structure and provided the new approachs which was not resolved in the materials science research area for the past few years. The nanotechnology research and development will produce new breakthrough in the aspects of information technology, advanced technique of manufacture, medicine and health, environment, energy as well as national security, and so on. A favorable material in the multitudinous nanomaterials is a kind of hollow tubal-shape structure material—Carbon Nanotubes. The Nobel chemistry prize winner Smalley has said that the carbon nanotubes will be a kind of low-cost, environment friendly new material, which can create the miracle for humanity.Since discovered by doctor S.Iijima of Japanese Electron Company's in 1991, carbon nanotubes was called the future super fiber by scientists for their unusual physical and chemical performance, such as the high toughness, great electro-conductivity, fine field emission performance, good metallicity and the semi-conductive property. All of these are attracting the scientists devote into the research of carbon nanotubes deeply. At present, plane display approached practicality using the field emission characteristic of carbon nanotubes. The work of manufacturing new electronic device is developing roundly that used the semiconducting characteristic of carbon nanotubes. The high strength fiber produced using the mechanical property of carbon nanotubes has already equipped US Parachute troops. Each government is exerting their utmost to solve the energy crisis and the environmental pollution problem by the preparation of the energy storage material using the adsorptive characteristic of carbon nanotubes. The application on biological detection has been progress badly based on carbon nanotubes. Comparing with other analysis methods, the electrochemical sensor has many merits, for instance, the portability, low cost, high sensitivity, best stability and so on. Carbon nanotubes are fine material on modified electrode and electrochemical sensor because it is nanomaterial and it could introduce its excellent charictristic on the surface of electrode, such as small diameter and big ratio surface area effect. The function groups on the surface of carbon nanotubes could catalyze the electrochemical behavior of some substance and exhibit in reducing oxidate potential, increasing peak current, improving analysis performance and enhancing the selectivity and sensitivity of the method.There is big room for the synthesis, modified and pretreatment of the carbon nanotubes at present. This article summarized the domain research situation of the preparation, purification, modifiability of carbon nanotubes and studied the modified and applications of the carbon nanotubes on DNA biosensor simultaneously. Another important work lies in the synthesis of aligned carbon nanotubes under the low pressure and applications of aligned carbon nanotubes in the glucose biosensor and the nitrite sensor. The aim of all the above investigation is to promoting the development of the carbon nanotubes in electroanalitical chemical domain. This paper altogether divided into three parts. The details are given as follows:Part One: PrefaceIn this chapter, we elaborated review from the discovery to the applications of carbon nanotubes on electrochemistry to the present. The discovery, the classification and the structure, the preparation method, the growth mechanism, the test, separation and purify, the characteristic, chemistry modification and application, present situation and the research prospect all have been introducded. In which emphatically introduced the physical and the chemical characteristics, the chemical modification, the preparation and the electrochemical application of carbon nanotubes. Finally, expounded the aim and the significance, pointed out the research content and the innovation in this paper. Part Two: Electrochemical Biosensor Based on Multiwalled Carbon NanotubesChapter One: Electrochemical Detection of DNA Hybridization Using Zirconia Nanoparticles Supported on Carbon NanotubesZirconia (ZrO2) is a kind of inorganic oxide and it has merits of thermal stability, chemistry inertia and nontoxicity, moreover it also has good affinity with the oxygenous groups. In this article we deposited the zirconia nanoparticles onto the surface of carbon nanotubes by using the liquid phase deposition method. Then dissolved it in DMF and drop the compound onto the surface of carbon nanotubes and the modified electrode was obtained. There is strong affinity between Zirconia and PO4-DNA through which the PO4-DNA could be immobilized on the surface of electrode.After hybridized with ds-DNA, the peak current of DNR was increased. The cathodic peak current of daunomycin after hybridization with the target DNA was linearly related to the logarithmic value of the target DNA concentration ranging from 2.25×10-9 to 2.25×10-12mol/L. A detection limit of 1.43×l012mol/L of oligo-nucleotides can be estimated.Chapter Two: Electrochemical Detection of DNA Bybridization Using Nile Blue and Au Nanoparticles Supported on Carbon Nanotubes Modified ElectrodeDue to the good catalytic activity of gold (Au) nanoparticles to the electrochemistry hybridizing indicator Nile Blue (NB) and the good charge transport characteristic of carbon nanotubes, a novel and sensitive electrochemical DNA biosensor is described. First, synthesized the Au nanoparticles with the diameter of 16nm and mixed it with the carboxylic carbon nanotubes in Nafion solution. Oligonucleotide probes with amido group at the 5' end were attached onto the carboxyl supported on carbon nanotubes. Nile blue (NB) is the hybridizing indicator and the experimental parameter of NB was detected. The complementary DNA detection sensitivity was dramatically increased.Part Three: Electrochemical Sensor Based on Aligned Carbon Nanotubes Chapter One: Synthesis of Aligned Carbon Nanotubes with Low Pressure by CVD of FePcOrgano-metal phthalocyanine iron (FePc) is the raw material because it would pyrolysis and simultaneously produce the catalyst in the process of CVD synthesis of aligned carbon nanotubes. Through the adjustment of the pressure of the vacuum reaction chamber, the pure aligned carbon nanotubes were obtained and it also reduced the experimental cost effectively which provide significance to the practical application research of aligned carbon nanotubes. SEM, FESEM and TEM was used as the analysis methods on the appearance of aligned carbon nanotubes which was growned on quartz basis. Batch production of big area, exact directional aligned carbon nanotubes has been obtained through improved and optimized the craft parameter. Simultaneously we also discussed in detail the the influence of craft parameter to the aligned carbon nanotubes. The field launch performance and the ultra electric capacity characteristic are studied in the article.Chapter Two: Glucose Biosensor Based on Pd Nanopartides and Glucose Oxidase on Aligned Carbon Nanotubes ElectrodePd is the catalyst in some chemical reaction for its stable, acidproof character. The Pd compound could be easily pyrolyzed and be deoxidizec to Pd(0), simultaneously Pd presents the tendency to form the coordination compounds intensely. In this article we introduced the outstanding nature of Pd nanopartides such as the easy formation of the coordination compound, the big surface area, the high surface reaction activeness, the much activity center of its surface, the high catalyzed efficiency, the strong adsorptive capacity into the glucose biosensor research. The enzyme electrode exhibits excellent response performance to glucose with linear range from 3×10-5-6×10-4mol/L at the working potential of 0.4V. A detection limit of 7.26×10-6 is observed with this biosensor when signal to noise is 3.Chapter Three: Glucose Biosensor Based on Pt Nanoparticles and Glucose Oxidase on Aligned Carbon Nanotubes Electrode A sensitive amperometric glucose biosensor based on platinum nanoparticles (PtNPs) combined aligned carbon nanotubes (ACNTs) electrode was investigated. PtNPs which can enhance the electrocatalytic activity of the electrode for electro-oxidating hydrogen peroxide by enzymatic reaction, were electrocrystallized on 4-aminobenzene monolayer-grafted ACNTs electrode by potential-step method. These PtNPs combined ACNTs' (PtNPs/ACNTs) surfaces were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The highly dispersed PtNPs on ACNTs can be obtained. The enzyme electrode exhibits excellent response performance to glucose with linear range from 1×10-5～7×10-3 M and fast response time within 5s. Furthermore, this glucose biosensor also has good reproducibility. It is demonstrated that the PtNPs/ACNTs electrode with high electrocatalitic activity is a suitable basic electrode for preparing enzyme electrodes.Chapter Four: Determination of Nitrite with the Electrocatalytic Property to the Oxidation of Nitrite on Thionine Modified Aligned Carbon NanotubesA thionine modified aligned carbon nanotubes (ACNTs) electrode was fabricated and was used to electrochemically determine nitrite. The thionine modified ACNTs electrode exhibited enhanced electrocatalytic behavior to the oxidation of nitrite. The electrochemical mechanism of the thionine/ACNTs electrode towards the oxidation of nitrite was discussed. The thionine modified ACNTs electrode exhibited fast response towards nitrite with a detection limit of 1.12×10-6 mol L-1 and a linear range of 3×10-6～ 5×10-4 mol L-1. The proposed method was successfully applied in the detection of nitrite in real samples. |
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