| Two parts are included in this thesis. In the first part of this thesis, the properties of reactive oxygen species (ROS) and their analytical applications in CL analysis are reviewed. In the second part, we mainly focused on the study of the analytical characteristics of two sorts of ROS, superoxide ion and singlet oxygen, which were used as Chemiluminescence oxidants in CL reaction, respectively.Chemiluminescence is the electromagnetic (ultraviolet, visible, or near infrared) radiation by molecules or atoms resulting from a transition from an electronically excited state to a lower state (usually the ground state) in which the excited state is produced in a chemical reaction. Because the emission intensity is a function of the concentration of the chemical species involved in the CL reaction, measurement of emission intensities can be used for analytical purposes. The usefulness of CL systems in analytical chemistry is based on some special characteristics, such as high sensitivity, excellent detection limits (down to sub-femtomole levels in some cases), dynamic working range over several orders of magnitude, employments of the relatively simple instrumentation and so on. For a reaction to produce detectable CL emission, it must fulfill the following condition: A sine qua non for CL to occur is that the precursor(s) of the light-emitting species must participate in a reaction that releases a considerable amount of energy. For visible emission (say 400-750 nm in wavelength) 171-299 KJ·mo1-1 is required. Secondly, there should be a suitable reaction pathway for the excited state to be formed. Thirdly, a radioactive pathway for the excited state to lose its excess energy should exist, which has high quantum efficiency (quantum yield).ROSs can generate electronically excited products, which emit the weak CL during their decay to the ground state. Although it is not easy to detect the light emission directly by CL techniques, it can be enhanced by CL reagents, such as luminol, lucigenin and so on. The purpose of this thesis was to study the CL analytical performances when ROS were used in CL reaction as the oxidants.In this thesis, superoxide ions, produced by electro-reducing oxygen in aqueous solution, and singlet oxygen, generated by photochemical reaction of hematoporphyrin, were used in CL reaction as oxidant respectively. Under this situation, the CL characteristics were studied in detail. The works are included in the followings:1. A novel method for immobilization of carbon nanotubes (CNTs) on the surface of graphite electrode was proposed, because the CNTs-CTAB complex can be well dispersed into liquid paraffin. We further found that superoxide ion was electrogenerated on this CNTs-modified electrode, which can reacted with sulfide ion combing with a weak but fast electrogenerated chemiluminescence (ECL) emission, and this weak ECL signal could be enhanced by the oxidative products of rhodamine B. In addition, the rate constant of this electrochemical reaction k0 was investigated and confirmed that the speed of electrogenerating superoxide ion was in accordance with the subsequent fast CL reaction. Thus, the fast CL reaction of superoxide ion with target brought in the possibility of high selectivity based on time-resolved, relative to other interferences. Based on these findings, an excellently selective and highly sensitive ECL method for sulfide ion was developed. Under the optimum conditions, the enhancing ECL signals were linear with the sulfide ion concentration in the range from 6.0×10-10 to 1.0×10-8 mol·L-1, and a 2.0×10-10 mol·L-1 detection limits (3σ) was achieved.2. Coupling of a photochemical reaction with conventional CL reaction, the generation of CL emission was initiated by the forward photochemical reaction products. Therefore, the photochemical reaction products of hematoporphyrin, singlet oxygen, was produced and took part in the subsequent CL reaction as an oxidant in situ, combining with a strong CL emission. Based on these considerations, the conventional CL reagents can be mixed in advance in static solution and the generation of CL emission was controlled by the first photochemical reaction. On the other hand, we investigated porphyrin and silver bromide in photo-induced CL instead of hematoporphyrin and they promised the similar kinetic curve. Due to the kinetic distinction between background (due to residual photos in solution after illumination) and CL signal, a time-resolved CL analysis for Hp determination was proposed. The photo-induced CL signals were linear with hematoporphyrin concentration in the range from 10 to 1200 ng·mL-1, and a 0.5 ng·mL-1 detection limits was achieved.
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