Electrogenerated Chemiluminescence On Nanaomaterial Modified Electrodes

In the general introduction of this thesis, the history, the materials and methods to modified electrodes, the basic principles, characteristics and the main systems of electrogenerated chemiluminescence(ECL) on the modified electrode are briefly introduced and the applications of ECL systems in the immunoassay, biosensors, pharmaceutical assay and reaction mechanisms in last ten years are intensively reviewed. In the research section, ECL on electrodes modified with nano-materials and polypyrrole is investigated.A highly sensitivite ECL method for determination of luminol on the Au nanoparticles modified graphite electrode is developed. The ECL behavior of luminal with hydrogen peroxide at a graphite electrode modified with gold nanoparticles(GN-GE) in 0.10M neutral phosphate buffer solution (pH 7.4, containing 0.10M KC1) is investigated. While an applied potential is scanned from 0 to 0.85 V, a sharp ECL peak is observed on the GN-GE at 0.65 V(vs. Ag/AgCl/sat. KC1) and a tiny shoulder ECL peak is observed at the GE. Moreover, the cyclic voltammetric measurements of luminol and hydrogen peroxide are made at the GE and the GN-GE. Although the oxidation current peaks of luminol decrease, the oxidation peak of the hydrogen peroxide drastically increases at the GN-GE. Based on the increased ECL, a highly sensitive ECL method for the determination of luminol is developed at the GN-GE. The ECL signals responded linearly to the concentration of luminol from 4 × 10-12mol/L to 1 × 10-10mol/L with the detection limit of 2.0 x 10-12mol/L.The enhanced ECL of lucignin on gold-nanoparticles modified glassy carbon electrode (GCGN) is investigated, the enhanced ECL is considered to be derived from the decomposition of a dioxetane-type intermediate formed by the radical-radical coupling reaction between an electrogenerated superoxide ion (02") and a one-electron reduced form of Luc2+(i.e.a radical cation, Luc+). The ECL intensity at nanogold-modified electrodes is about ten times higher than that at the bare electrode. The enhancement of ECL at the nanogold-modified electrodes may be due to the concentration effect of positively charged Luc2+ ions and the adsorption prevention effect of ECL product i.e. N-methylacridone. A novel ECL method for thedetermination of lucignin is developed based on enhanced ECL of lucignin on gold-nanoparticles modified glassy carbon electrode. The analytical conditions were optimized. The ECL signals responded linearly to the concentration of lucignin from 8.0×10-7~ 7.0×10-5mol/L with the detection limit of 2.0×10-12mol/L. 3×10-7 mol/L.Eelectrogenerated chemiluminescence of tris(2.2'-bipyridyl)ruthenium(II) coated with overxidized polypyrrole on a glassy carbon are investigated, a novle method of preparing a glassy carbon modified with overoxidized polypyrrole coated tris(2,2'-bipyridyl)ruthenium(II) is described. The overoxidized polypyrrole films containing Ru(bpy)s2+ is used for ECL determination of TPA and oxalic acid. Moreover, comparing with the previous report of nafion films using modification of electrode, the surface of overcxidized polypyrrole films is positive charge in acid solution and negative charge in alkali solution. A novel ECL method for the determination of TPA and oxalic acid is developed based on ECL of tris(2,2'-bipyridyl)ruthenmm(II) coated with overxidized polypyrrole on a glassy carbon. The analytical conditions were optimized. The ECL signals responded linearly to the concentration of TPA from 8.0×104~5.0×10-6 M mol/L with the detection limit of 2×10-6mol/L. 3×10-7 mol/L and oxalic acid from 5.0×10-4 -2.0×10-5mol/L with the detection limit of 7×10-6mol/L.