【作者】 周元臻；

【导师】 郑建斌；

【作者基本信息】 西北大学 ， 分析化学， 2007， 博士

【摘要】 示波分析是高鸿教授在我国创立的一个电分析化学研究领域。本论文围绕示波分析在理论、仪器以及重叠切口解析等方面存在的问题，推导了脉冲示波计时电位理论公式和小示波图的端点电位公式，构建了基于LabVIEW的虚拟示波计时电位分析系统，提出了两种重叠切口解析的新方法。该研究对于进一步完善示波分析的理论、发展示波分析仪器、解决示波图上重叠切口解析问题，扩大示波分析的应用范围，进而丰富电分析化学的研究内容具有重要意义。全文共分五章，主要贡献如下：1、推导了脉冲示波计时电位公式。利用该公式能解释当施加于电解池的脉冲波交流电流的占空比变化时，示波图的阴极支与阳极支的长度比就会发生变化，使阴极支或阳极支上由去极剂产生的法拉第电流与充电电流的比值也随之发生变化，从而影响阴极支或阳极支上切口灵敏度的现象。与合作者一起提出了Hg-R₁和R₂-K两种类型小示波图，推导了小示波图的端点电位公式考察了R₂-K型小示波图的调节方法，并建立了基于小示波图的示波计时电位法。研究结果表明，将小示波图用于示波测定具有以下特点：①由于示波图的电位窗口较小，图形稳定性较好、共存物质的干扰较小。②由于小示波图所需的交流电流较小，使测定的灵敏度更高。③小示波图的i₀／i₁比值随小示波图类型变化。对于R₂-K小示波图，i₀／|i₁|更小；对于Hg-R₁小示波图，i₀／|i₁|更大，突显出直流电流在示波计时电位法中的作用，从而改变了大交流小直流是交流示波计时电位法的一个特征的说法，完善了示波法的理论。2、基于虚拟仪器技术，构建了基于LabVIEW的虚拟示波计时电位分析系统，并以高低频示波分析和神经递质多巴胺和肾上腺素的示波行为研究为例检验了该系统的性能。研究表明，该系统具有实时在线分析计算功能、可控信号显示及回放、数据的频谱分析和数据海量存储等功能。该系统的研制使高低频示波计时电位法等示波方法成为实际有用的分析方法。3、将小波变换与Fourier变换结合用于对频域信号的处理，提出了用频域小波变换获得的模糊项作为线性函数的Fourier自去卷积法（FWTL-FSD）和用频域小波变换获得的不同模糊项替代原始信号并作为线性函数的Fourier去卷积法（FWTLD-FSD），并用于示波分析中重叠切口和色谱重叠峰分辨。研究表明，经两种方法处理后的dE／dt-t曲线重叠切口深度均明显增加，可以明显改善多组分示波测定的下限和灵敏度；处理后的色谱重叠峰可完全实现基线分离。研究还表明，用FWTLD-FSD能对信噪比大于5的含噪信号进行分辨，但其分辨能力略逊于FWTL-FSD法。与传统的Fourier自去卷积方法相比较，两种新方法均具有不用选择线性函数和较好的重叠峰分辨效果等优点。4、将化学计量学中偏最小二乘（PLS）、主成分回归（PCR）及径向基神经网络（RBAN）分别用于示波重叠切口和色谱电化学重叠峰的解析，进行了示波重叠切口和色谱电化学重叠峰信号解析方法的比较研究。研究表明，无论对于示波计时电位（OCP）重叠切口还是高低频-示波计时电位（HL-OCP）重叠切口，RBAN均表现出了比PLS和PCR更好的分辨能力；而对于色谱电化学重叠峰，PLS和PCR解析效果要优于RBAN。可见，对于具有线性映射特性的重叠色谱电化学信号（浓度、峰面积）更适合用PLS、PCR等线性映射能力较强的解析方法来解析；而对于更多呈现的是非线性映射关系的示波重叠切口，需采用具有非线性映射能力的RBAN等解析方法，才能获得较好的解析效果。作者在攻读博士学位期间完成和发表论文13篇。更多还原

【Abstract】 Oscillographic analysis is an electro analytical chemistry field founded by Pro. Gao. This thesis is concerned with the problems that oscillographic analysis maintained in theory, instrument, resolving overlapped incisions and some other aspects. In this study, the theory formula of pulse current oscillographic chronopotentiometry and that of endpoint potential of small oscillogram were deduced. A virtual oscillographic chronopotentiometry analysis system based on LabVIEW was constructed and a new method for resolving overlapped incisions was presented. This study was significant in perfecting ocsillographic theory and instrument, resolving overlapped incisions of ocsillogram, enlarging the application of ocsillographic analysis, and further enriching the study content of electroanalytical chemistry. The thesis is divided into five chapters and the main work of author was described as follows,1. The theory formula of pulse current oscillographic chronopotentiometry was deduced. When the duty ratio of pulse alternate current applied over the cell has changed, the length ratio of cathodic branch of oscillogram to anodic one would be altered, which lead to the change of the ratio of the Faraday current to charging current and also the sensitivity of the incisions on the cathodic or anodic branch. Using the theory formula, the phenomena above can be explained.The author with his coworkers proposed two types of small oscillogram, Hg-R₁ and R₂-K. The adjustment method of the R₂-K. type small oscillogram was investigated and oscillographic chronopotentiometry based on small oscillogram was established. The research results showed that when the small oscillogram was used to oscillographic detection, three features would be obtained. Firstly, at the smaller potential window oscillogram, better oscillogram stability and smaller interference caused by coexisted substances can be acquired. Secondly, the determination at the small oscillogram would be more sensitive than the classic oscillogram for the fact that smaller alternate current was needed. Finally, the i₀/i₁ ratio of small ocsillogram changed along with the alteration of the type of small ocsillogram. The i₀/|i₁| of R₂-K type small ocsillogram is smaller than the classic one while the i₀/|i₁| of Hg-R₁ type small ocsillogram is bigger than the classic one, so the effect of direct current in oscillographic chronopotentiometry is manifested. Thus, the theory of the oscillographic analysis is developed.2. Based on virtual instrument technique, a virtual oscillographic analysis system was constructed using Labview software. The performance of the system was tested by the oscillographic chronopotentiometry with high and low frequency current and ocsillographic behavior of dopamine and adrenaline. The study indicate that this system have the ability of real-time analysis and computation, controlled data collection and wave display, magnanimity data storage, etc. Studies of this system make oscillographic chronopotentiometry with high and low frequency current （HL-OCP） and other oscillogaphic methods real applicable analysis method.3. Wavelet transform and Fourier transform were combined in processing frequency domain signals. Fourier deconvolution method （FWTL-FSD） of approximations obtained from frequency domain wavelet transform as linear function and that （FWTLD-FSD） of different approximations obtained from frequency domain wavelet transform as devoiced signals and linear function were presented and used in processing overlapped incisions and overlapped chromatographic peak signals. It shows that the overlapped incision depth of dE/dt-t curve increased obviously after resolution. Which indicates the methods can improve the determination limit and sensitivity of ascillographic muticomponent analysis. The result of resolving the overlapped HPLC peaks show all the signal peaks can achieve baseline separation. FWTLD-FSD method can be applied in resolving noisy signals with signal-to-noise ratio higher than 5, but a little inferior to FWTL-FSD method in sensitivity. Compared with classical FSD, the two novel method both exhibits some advantages such as good overlapped peak resolution, simple operation without selection procedure of the linear function.4. The resolution of overlapped incisions and overlapped chromatographic peak signals were processed by means of chemometric methods include partial least squares （PLS）, principal component regression （PCR） and Radial basis function networks （RBFN）. The comparing research of multivariate calibration of ocsillographic and chromatographic electrochemical signals was carried out contemporarily. From the research, it can be indicated that RBAN model exhibits much better resolution ability than PLS and PCR in resolving overlapped OCP incisions as well as overlapped HL-OCP incisions; but to chromatographic electrochemical overlapped peak signals, PLS and PCR model have better effects. It can be draw out that resolution method with linear mapping ablitiy such as PLS, PCR is more adequate for resolving chromatographic electrochemical overlapped peak signals （concentration, area） with linear mapping characteristics; For oscillographic overlapped incisions of two components study system presenting nonlinear mapping relation mainly, resolution method with nonlinear mapping ability, such as RBAN, can carry out good results.During the study of doctor’s candidate, author has completed and published 13 papers.更多还原