| In this dissertation, in order to develop a novel composite film modified electrode,a poly-?dopamine-co-aminophenol??poly-DCA?, 3d-4f hybrid metallic cyano-bridged mixed coordination polymer?CyMCP?, the particles of liquid mercury or metallic cooper were plated step by step onto a glassy carbon electrode?GCE? by the electrochemical method. The modified electrode was especially suitable for stripping voltammetry due to its good stability, selectivity and repeatability for the signal response. Therefore, we investigated the anodic stripping voltammetric behavior at the Hg-droplet/poly-DCA/CyMCP/GC modified electrode and established the electroanalytical method for the simultaneous determination of Cu?II?, Pb?II?, Cd?II? and Zn?II? in water samples. In addition, based on the sensitized cathodic electrochemiluminescence of?Ru?bpy?3?2+/1+ system on the Hg-droplet /poly-DCA/CyMCP/GC electrode, we also developed the analytical method for the quantitative determination of nicotinamide adenine dinucleotide?NAD+? concentration. Moreover, the electrocatalytic reduction behavior of hydrogen peroxide was studied using in situ plated Cu film on the poly-DCA/CyMCP/GC electrode, and the some explorative experiments were done for the determination of H2O2.This paper consists of four chapters.Chapter 1: A literature review on this research.This section consisted of the following parts:?1? Chemically modified electrodes;?2? Introduction of several polymer materials for the modified electrodes?3? The electrodes modified with micro and/or nano particles of metal materials;?4? The composite mercury film modified electrode;?5? The significance and innovation of my studies.Chapter 2: Simultaneous determination of Cu?II?, Pb?II?, Cd?II? and Zn?II? in water samples by stripping voltammetry on the composite mercury film modified electrode.In this work, we successfully prepared a novel composite mercury film modified electrodes?CMFMEs? for stripping voltammetry. The prepared electrode comprised of three modification layers on a glassy carbon substrate: a poly-?dopamine-coaminophenol??poly-DCA?, 3d-4f hybrid metallic cyano-bridged mixed coordination polymer /CyMCP) conductive polymer layer and a uniform micron-level Hg-droplets layer. Optical microscopy showed that the diameter of maximum Hg-droplets at the array distribution plane was approximately 1.7 ?m. After examining and optimizing the accumulation potential, the accumulation time and the composition of the supporting electrolyte, with aid of the excellent performances of the CMFMEs, we could simultaneously determinate the concentration of Cu?II?, Pb?II?, Cd?II? and Zn?II? without need of the deaerated pretreatment for a sample solution. The results demonstrated that the proposed method was very fit for the measurement of a water sample coexisting the four metallic ions within a shorter accumulation time?80 s?, and strictly conformed to a two-segment linear response curves from 1.0×10-9 to 3.3×10-5 M for Cu?II?, Pb?II? and Cd?II?, respectively.(but for Zn?II? from 1.0×10-6 to 3.3×10-5 M). And the nicer performances of CMFMEs for the stripping analysis of the four heavy metallic ions were superior to those offered from previously reported MFEs in terms of sensitivity, reproducibility and useable endurance.Chapter 3: Determination of nicotinamide adenine dinucleotide oxidized form?NAD+? by using cathodic electrochemiluminescence method at a composite mercury film modified electrode.In this work, the composite mercury film modified electrode?CMFME? with Hg-droplets array was prepared by the multi-step electrochemical method. Because the NAD+ had the enhancing effect for cathodic electrochemiluminescence of?Ru?bpy?3?2+/1+ system at the CMFME, we established the new analytical method to determinate the content of NAD+. The experimental results showed that there are good the double logarithm linear relationship between ECL intensity of Ru?bpy?32+/1+ system and the concentration of concomitant NAD+ in range of 10-8- 10-6 M. And the linear regression equation, the correlation coefficient and the detection limit were shown as lg I= 4.7446+0.1442×lg C, R2=0.9986 and 3.2×10-9 M?S/N=3?, respectively. Thus, the novel method was validated to hold the high sensitivity and selectivity for the assay of NAD+.Chapter 4: Determination of H2O2 by using cathodic stripping voltammetry at the poly-DCA/ CyMCP/GC electrode.In this work, the electrocatalytic reduction behavior of hydrogen peroxide was studied using in situ plating Cu film on the poly-DCA/CyMCP/GC electrode in the strong acidic electrolyte. Subsequently, we had established to the new method for determination of H2O2 by difference pulse cathodic stripping voltammetry?DPCSV?. The experimental results showed that H2O2 could generate a distinct electocatalytic reduction peak at the negative potential region about-0.65 V?vs. Ag/Ag Cl? on the composite modified electrode. Under the optimum conditions, there existed the double logarithm linear relationship between the cathodic reduction peak current of H2O2 and its concentration in the range of 0.5-160 m M. And the linear regression equation and the correlation coefficient were shown as lg?Ip? =-2.293+0.881 lg C and R2= 0.9986, respectively. Eventually, the present methodology showed good precision and high accuracy for the quantitative determination of H2O2... |
PDF Full Text Request