Electrochemiluminescence Studies Of Chlorophyll (a+b) Potassium Salt In Aqueous Solution And An Optical Oxygen Sensor Based On The Quenching Of Fluorescence From A Ruthenium (Ⅱ) Complex Ru(bpy)₂(dpp)～(2+)

Two parts are included in this thesis. In the first part of this thesis,the electrochemiluminescence(ECL) behavior of chlorophyll potassium salt in aqueous solution was studied under conventional cyclic voltammetry(CV). In the second part of this thesis,we mainly concentrated on the study of an optical oxygen sensor based on fluorescence quenching of Ru(bpy)2(dpp)2+ immobilized on sol-gel-derived porous silica coatings.Electrochemiluminescence (ECL) is a new analytical technique, which is developed based on the combination of electrochemistry with chemiluminescence. It not only has high sensitivity, but also is easier to control the process of chemiluminescence by adjusting the potentials. Therefore, it has been attracted by more and more chemists.Since the luminol-based ECL phenomena was firstly observed by Harvey in 1929,the ECL was paid much attention by the analysts,and a lots of analytes had been detected with ECL analytical technique during the 1980s and 1990s. This approach has many obvious advantages over other analytical methods,and it has been applied successfully to many fields, such as life science, clinical medicine,environment, immunoassays and DNA probe analysis etc. Nowadays, analysts are working on biological chip and exploiting ECL substance etc.ECL measures relative dynamic luminescence and electrochemical parameters during the process of electrochemical reaction. There are many factors, which would affect the result of measurement, and the preconditions of analytical application can be optimized to improve the selectivity and reliability of the method. Though combining flow injection analysis (FIA) with ECL redounds to reproducibility and relative easiness to be automatically controlled, it is not propitious to biological and pharmic applications due to the sample volumes and reagent consumption. Therefore, the study was focus on static ECL in the whole thesis.The electrochemiluminescence (ECL) behavior of chlorophyll potassium salt in aqueous solution was studied under conventional cyclic voltammetry (CV). The ECL response of O2 and CO2 was 40 times as weak as that of N2. A possible mechanism for the behavior was proposed and the difference of ECL intensity between N2, O2 and CO2 is explained. It gives a potentially fast and inexpensive method for the application in gas sensors.In the second part, a dissolved oxygen sensor based on the quenching of fluorescence from a ruthenium (Ⅱ) complex Ru(bpy)2(dpp)2+ immobilized in a sol-gel silica film is reported. Sol–gel-derived silica films were fabricated by dip-coating on to glass substrates. Organically modified sol-gel precursors methyltriethoxysilane (MTEOS) was used in the sol-gel process. The results indicate that the MTEOS-based film doped with Ru(bpy)2(dpp)2+ has a sensitive response to dissolved oxygen. It shows a good linear response in the range of 0 to 39.91 ppm of dissolved oxygen. The sensor exhibits good reproducibility, high photostability, no hysteresis and long lifetime.