Synthesis Of Fluorescent Indicators For Phosphate And Study On Its Photochemical Sensor And

Phosphorus is not only the important resource element in oceanic environment, but a restrictive nutrition element in water system. Its ebb and flow, and the state of phosphate determines the oceanic productivity and the maintenance of oceanic zoology system. Especially near the shallow sea, the phosphorus pollution has seriously influenced the oceanic zoology and development of fishery because of large amount of consumption of the phosphorus-containing scours and fertilizers in the past decades. As a result, people have paid more and more attention to the development of phosphate sensor apparatus which can be used to determine the concentration distribution and its change of phosphate in the seawater on line and in real time. In the first chapter, we explained the necessity and imminence of the phosphate detection in three areas including the form of existence and inter-transform of phosphorus in nature, the origin, the status quo and results of phosphorus pollution and the significance of phosphate detection. As followed, the traditional detection technologies and the developments of fluorescent indicator of phosphate were reviewed from two aspects of spectro-photometry and molecular fluorescence photometry. At last we summarized the application development and the compare of advantage and disadvantage of the electrochemical sensor, the biochemical sensor and the photochemical sensor in the field of phosphate detection in the past years. In the second chapter, we introduced with the emphasis on the synthesis methods of three newly reported phosphate fluorescent indicators, of which, the sensitivity and selectivity were the best of all candidates: Tri[N'-naphthyl-N-(2-ethyl)urea]amine, Tri[5-chlorine-1-sulfanilamide-naphthyl-ethyl]amine, 1,8-N,N'-diimidazole-cyclo-dianthracene. Meanwhile, the FTIR, UV, MS and fluorescence spectrum were utilized to analyze the three final products and many mid-products roundly. In addition, the fluorescent response behaviors of three indicators, in both organic solution and aqueous solution after they were fixed on the sol-gel membrane, were examined to conclude that Tri[N'-naphthyl-N-(2-ethyl)urea]amine is the best phosphate fluoresce-nt indicator to work on the sol-gel membrane. In the third chapter, we discussed the response mechanism of the indicator Tri[N'-naphthyl-N-(2-ethyl)urea]amine and phosphate on sol-gel membrane at first, then we reviewed the organic quality-altering sol-gel technology and the orthoganality experiment method which were utilized in this article to examine the effects of water R(H2O), mellow R(ROH), catalyzer R(HCl), additive R(DCCA) and water-dropping rate, heating temperature, stirring time etc on the membrane quality. In addition, we examined the affecting degrees of many other factors of membrane preparation technics, and optimized them with great improvement. In the optimization of determining system, we examined the effects of system acidity, different buffer solutions, system temperature, membrane thickness etc on the membrane performance in the aqueous solution, then the working curve and limit of detection(LOD) were also examined. At last, we investigated the interference of other ions, stability, reversibility, response time, working life and some other characters of the sensor membrane. In a word, we've carried out large amount of investigations and explorations on developing and synthesizing the sensitive, reversible fluorescent indicators of phosphate, and studied the organic quality-altering sol-gel technology in detail in order to embed the indicator effectively into the sol-gel membrane. Now we've mastered the organic quality-altering sol-gel technology in the preparation of photochemical sensor, and afforded new basis of theories and experiments on studying and developing the real-time and on-line phosphate photochemical sensor.