A Luminol-Based Flow-Injection Electrochemiluminescent System To Determine Reactive Oxygen Species

Electrochemiluminescence involves the generation of species at electrode surfaces that then undergo electron-transfer reactions to form excited states that emit light. Flow injection analysis is an automated method in which a sample is injected into a continuous flow of a carrier solution that mixes with other continuously flowing solutions before reaching a detector. Flow injection analysis combined with electrochemiluminescent detection, which is a quick analytical technology with high sensitivity and wide linear range, is being used in environmental analysis, food chemistry, life science and so on. A facile and masterly luminol-based flow injection electrochemiluminescent system for the determination of ROSs was developed in this research. The thesis is composed of four parts.In the first part, both electrochemiluminescence and flow injection analysis were reviewed, including the fundamental theory, history, characteristics and so on. And the goal and significance of this paper were introduced.In the second part, a flow injection analytic system with an electrochemiluminescent detector has been established. The system based on a specially designed flow-through ECL cell, which possessed simple structure, rapid response and high sensitivity. With luminol as electrochemiluminescent reagent, the stable background was gained.In the third part, the response of hydrogen peroxide was investigated on proposed FIA-ECL system with a pulse ptential. After optimizing the experimental conditions such as electric parameters, the buffer condition and the flow rate etc, it was proved that the proposed FIA-ECL system worked well for quantified assay. And the method was successfully used to monitor ROSs in the water vapour of ultrasonic humidifier.In the fourth part, the system was used to determine ROSs in trace level in potentiostatic mode. Comparison with reported papers, the results indicated that the proposed FIA-ECL system had lowest detection limit of 3.0×10^-9 mol/L for H₂O₂ which reached to the level of chemiluminescence (CL). Ultimately, the amount of reactive oxygen species with H₂O₂ as index in real samples as tap water, drinking water, river water and water vapour of ultrasonic humidifier were detected with the recovery of 92.0% to 106%.