The Fabrication Of The Disposable Thin-layer Chromatography Electrode And Its Application In Electrochemiluminescence Analytical Method

Two parts, review and research report, are included in this thesis. In the first part of this thesis, the basic principle and characteristics on electrochemiluminescence (ECL) analysis are introduced. In addition to these, research background and the applications of ECL analysis on chemically modified electrodes in analytical chemistry field are also reviewed in this part. In the second part of this thesis, we mainly concentrate on the fabrication of the disposable carbon thin-layer chromatography electrode and its application in luminol ECL analytical systems.ECL analysis involves the generation of reactive species during an electrochemical reaction that then diffuse from the electrode and react either with each other or with chemicals in bulk solution, to form excited state molecules that emit light by relaxation, and is a product of the combination of electrochemistry methods with chemiluminescence analysis. So it not only retains much advantages of the conventional chemiluminescence (CL), such as high sensitivity, wide linear range, less analytical time, simple apparatus and so on, but also processes some advantages itself. For example, some unstable reagents for ECL reaction can be in-situ produced, and the electrochemical initiation of the ECL reaction also introduces great temporal and spatial control over the reaction. Since N. Harvy fortunately observed the ECL of luminol in alkaline solution in 1929, the prelude of the ECL investigation had been discovered. But in a very long time, seen from its investigated range, the development of ECL analysis was quite slow due to the absence of enough means and technology. After the 1980S, ECL analysis developed very quickly, and was regarded as one aspect of the most developed prospects in analytical chemistry in the 21st century. However, in the recent years, the studies in analytical chemistry haven't been limited in the developments and applications of new methods, but more and more, have been switched to improving the sensitivity and the selectivity of analytical methods, and integration, miniaturization and portability of analytical equipments. In these aspects, ECL analysis processes great potentials.In this thesis, the research work focused on the fabrication of the disposable carbon-film electrode with separate functions of thin-layer chromatography based on chemically modified electrode techniques, and the investigation of ECL analytical performance on the chemically modified electrode by using the spatial-resolution ability of ECL signal at the surface of electrodes, which was divided into two parts. (1). The study of a novel method for fabricating disposable carbon-film electrodesIn order to fabricate them with simple methods and cost-effective materials, we put forward a novel method for fabricating disposable carbon-film electrodes by using a steel mould in PVC soleplate. The results showed that electrodes prepared in this method, had better ECL reponse (RSD=1.5%, Ciw=2.0x 10'6mol/L, ?=8 ) , and were easy to be modified to realize the combination of ECL analysis with thin-layer chromatography analysis. (2). Fabrication of disposable carbon film electrodes modified with cellulosemicrocrystalline or silica gel and the investigation of its ECL performance.Our studies indicated that cellulose microcrystalline, which was often used as a stationary gas in the thin-layer chromatography analysis, could be modified at the surface of disposable carbon-film electrodes to fabricate thin-layer chromatography electrodes. Further studies showed that, based on both the separation behavior of the thin-layer chromatography of Ni2+ on the surface of this electrode and its enhancing effect for the weak ECL signal of electro-oxidation luminol in the mixing solution of the 7-I-8-H2QS with borax buffer, a highly sensitive and selective ECL method for the determination of Ni2+ was developed in the present paper. Under the optimium experiment conditions, the linear range of the proposed ECL method for Ni2+ was from 5.0x10'9 g/ml to 1.0xl0"6g/ml with a detection limit of 1.5x10"9 g/ml.A disposable carbon-film electrode, modified with cellulose microcrystalline, could make lead (II) ion retain and concentrate on a certain region of surface of this modified electrode through thin-layer chromatography development. Furthermore, it was found that Pb-7-I-8-H2QS could enhance greatly ECL intensity of electro-oxidation luminol itself at the modified electrode in alkaline medium. Based on these observations and the spatial-resolution ability of the ECL analysis, a highly selective ECL method for the determination of lead (II) ion has been proposed in the paper. Under the optimized conditions, the relative ECL signals responsed linearly to the concentration of lead (II) ion from 8.0* 10'8 g/ml to 8.0xl0~6 g/ml. And the limit...