Five Functions Of Nanomaterials-based Electrochemical Sensor Configuration Set And Its Application

Using new materials, including nanomaterials, and composite materials in construction of high sensitive and selective electrochemical sensor has already been active area of modern analytical chemistry study. In this thesis, five kinds of new electrochemical sensors based on nanomaterials and composite materials are fabricated, after which the electrochemical behaviors are studied in details. The new voltammetric analytical methods for H2O2, HCHO, N2H4, AA, DA and UA are set up. These studies may provide new thoughts for the construction of high sensitive and selective electrochemical sensor and broadens the application range of nanomaterials and composite materials. The thesis consists of five chapters and the author's main contributions are as follows:1. Two electrochemical sensor ultalizing alloy nanoparticles are proposed. The former is based on the electrodeposition of AgPd alloy nanoparticles on chitosan(Ch)-ionic liquid gel film. The latter is based on the electrodeposition of PdNi alloy nanoparticles on chitosan(PEDOT)-graphene (GE) composite film. The electrochemistry and electrocatalysis of two sensors are investigated, and then new methods for HCHO and N2H4 determination are established. The research shows that the former exhibits a significant electrocatalytic activity toward HCHO. The oxidation peak current is linear with the concentration of formaldehyde in the range of 0.060 mM-20 mM with a detection limit of 0.022 mM. The latter exhibits a significant electrocatalytic activity toward N2H4. The oxidation peak current is linear with the concentration of f N2H4 in the range of 1μM-2.1 mM with a detection limit of 0.32μM. The HCHO sensor is shown to possess remarkable catalytic activity, good tolerance to CO poisoning and enhanced selectivity for the electrochemical oxidation of formaldehyde. The N2H4 sensor exhibits high sensitivity, good stability, fast response and low overpotential.2. Potentiostatic double-pulse method is used to prepare the Ag NPs/ZnO nannocomposites, and the electrochemistry and electrocatalysis of Ag NPs/ZnO are investigated. The PANI-SWCNTs composite film is synthesized in ionic liquid, and the electrochemistry and electrocatalysis of PANI-SWCNTs composite are investigated. Two nonenzymatic H2O2 sensors are proposed on the basis of the effective electrocatalytic activity of the Ag NPs/ZnO composite and PANI-SWCNTs composite towards reduction of H2O2. The former exhibits good linear behavior in the concentration range from 2μM to 5.5 mM for the quantitative analysis of H2O2 with a detection limit of 0.42μM. The latter exhibits good linear behavior in the concentration range from 5μM to 1 mM for the quantitative analysis of H2O2 with a detection limit of 1.2μM. The former is shown to possess superior properties of high sensitivity. The latter is shown to possess superior properties of good selectivity.3. HRP-SWCNTs-HA/GCE and HAp-GE-Hb/GCE chemically modified electrodes are fabricated, and the electrochemistry and electrocatalysis of HRP and Hb are investigated, and then new methods for H2O2 determination are established. The research shows that HRP and Hb molecules in the composite films retain their native structures and achieve their direct electrochemistry. The chemically modified electrodes show excellent electrocatalytic activity toward H2O2. The above studies indicate that novel nanocomposite can not only accelerate the direct electron transfer of redox proteins (enzymes) but also show excellent biocompatibility.4. A multifunctional electrochemical sensor based on AgHCF-PEDOT-GE ternary nanocomposite film modified electrodes is proposed. Electrochemical behavior of AA, DA, and UA is investigated at the modified electrode, and a differential pulse voltammetry method for simultaneous determination of AA, DA and UA is set up. The reults show that the chemically modified electrode shows excellent electrocatalytic activity toward AA, DA and UA. Shown by the results of differential pulse voltammetry, it has a good linearity of 1-2000μM,2-500μM and 0.8-500μM for AA, DA and UA, respectively. The sensor exhibits wide linear range and low overpotential.