高分辨伏安法与电化学谱研究

1. A detailed investigation of resolving and quantifying the overlapped chemical signals by using wavelet transform (WT) was carried out, and the relevant theory was also provided. The innovative work mainly focused on the four aspects as follows: (1)Using the special wavelets, which included Marr, Haar and DOG for the continuous wavelet transform (CWT) and biorthogonal wavelet for the discrete wavelet transform (DWT), the peak positions of the component's responses, described by Gaussian, Lorentzian and sech2-function, could be determined via WT from the overlapped signals. The corresponding theoretical bases were also presented in this work.(2)Depending on the linear property of WT, a new method to construct the suitable baseline for quantitative analysis of the overlapped square wave voltammogram (SWV) of two components in WT domain was proposed. The relative satisfactory results of evaluating the peak height could be achieved by using the graphical measures established on this appropriate baseline in the case of different dilations or resolutions, degrees of separation and parameters of the peak (peak width and peak height). (3)Using Marr wavelet, the essence of CWT of the signal was discussed. Combining the definition of CWT and the derivative property of convolution, we constructed a general method to calculate the approximate derivative of signal through CWT by using the first and second derivative of Gaussian function, Haar, and the first derivative of three-order-Spline function as wavelets. (4)An algorithm, cross-iterative algorithm of continuous wavelet transform and original signal (CIACWTOS), based on finding the peak positions by using the Marr wavelet through the CWT, was established on to locate the refined peak positions. On the basis of CIACWTOS, a new method, flip shift subtraction method (FSSM), was proposed to separate the overlapped SWV of the two components. Depending on the validation of simulated signals and real data, the results showed that FSSM was a simple method, and could be utilized to separate the two peaks efficiently. Meanwhile, the introduced errors of FSSM were relatively small. 2. Amelioration of polyaniline modified electrode was studied to enhance and prove its selectivity and sensitivity. The mainly innovative work is as follows:(1) A new conducting polymer PNAANI was synthesized at glassy carbon electrode by electro-polymerization. The over-oxidized PNAANI/GCE was used for selective determination of dopamine (DA) in the presence of large excess of ascorbic acid (AA), and the detection limit was 1.68×10-8 mol/L. The high sensitivity was attributed to the preconcentration of DA cations in the film and the high selectivity was due to the charge discrimination effect.(2) It was found that a novel β-CD/PNAANI/GCE can successively be fabricated by electro-oxidizing the PNAANI/GCE in a β-CD/DMSO solution. It was demonstrated that the β-CD/PNAANI/GCE was sensitive to thymine. The voltammetric detection limit was 6.2×10-6 mol/L. An inclusion-catalytic oxidation mechanism was proposed for the reaction system. In addition, it was also demonstrated that β-CD/PNAANI/GCE was very sensitive to uric acid (UA), and the detection limit was 2.8×10-6 mol/L. Explanation of the selective inclusion-oxidation reaction of UA at the electrode was given by the mechanism of static effect.(3) PNAANI nanoparticle modified aspartic acid grafting GCE was fabricated. The PNAANI nanoparticles with uniform size of 100 to 300 nm were successively electro-synthesized on the aspartic acid grafted film acted as a template. It is the first report that the amino acid grafting film acts as nano template, which may provide a new type of template method for preparation of metal nanoparticles and other conducting polymer nanoparticles. The formation mechanism of polymer nanoparticles was proposed.(4) A nano-PNAANI/Nafion composite film was prepared by electrodepositing N-actylaniline on Nafion/GCE. The PNAANI nanoparticles formed showed a much smaller size of 100 nm and dispersed more uniforml

本项研究工作以子波变换与子波分析为基础，首次提出了高分辨伏安法和电化学谱及电化学能谱的概念，创立电化学谱分析法的理论基础和实验技术，研究各种电化学体系的谱线特征，探索电子交换反应，动力学参数以及电极表面吸附效应等对电化学谱的影响和贡献，旨在发展和丰富电化学与电分析化学的基础理论，开拓新的电化学研究与分析方法。