| The preparation of chemical and biological sensors is one of the hot topics of the field of Analytical Chemistry. There are many reports on various kinds of chemical and biological sensors in literature. Oxygen is considered to be one of the most important elements for one to be alive. So the preparation of oxygen sensors, especially dissolved oxygen sensors with high sensitivity, have gradually become the major interest aims of the field of optical chemosensor. The sensitivity of the existed dissolved sensors is not satisfying. Much more work need to be done. The paper aims at the support system of immobilized sensitive material, so as to develop new useful oxygen sensors. The Ru( Ⅱ) diimine complexes are the most widely used of all the oxygen sensitive materials. There are many reports about detection on gaseous oxygen and dissolved oxygen in literature, and the response of the sensors to oxygen based on the sensitive material of the Ru( Ⅱ) complexes accord with Stern-Volmer equation. However, the question confronted with frequently is that the salt such as chloride is dissolvable. So the dyes may be leak when it is immobilized in the medium of hydrophobe. The paper has researched various oxygen sensors, in which [Ru(bpy)3]Cl2 adsorbed onto silica particles codoped with various metal-ions as support system. The results of the response of the system to oxygen showed that the responses were different when different kinds of metal ions were codoped. Compared with reference, the fluorescence intensity was enhanced after codoped with Co2+ , Sn2+ , Th4+ , Zr4+ ,Bi3+(5.0×10-4mol/L),La3+(10-3mol/L )and decreased after codoped with Pb2+,Ti4+,Mn2+,Fe3+,Ce4+(5.0×10-4mol/L),Ag+(2.5×10-4mol/L).The experiments of codoping with different concentration of Ag+ and La3+ were shown that the relative fluorescence intensity was all decreased after different concentration of Ag+ were codoped with , but the result was contrary for La3+. We suggest that the former has formed dark-brown Ag2O which can adsorb a part of excited light, given rise to the decrease of fluorescence intensity. The increase of the latter probably because the energy transfer of La increased the fluorescence. In addition, the paper has adopted the electroless composite plating method as to achieve the co-sediment of silica particles, Ni and [Ru(bpy)3]Cl2 through the research and improvement of the techniques of electroless composite plating, the composite coating of Silica-Ni-P was obtained. After the coating was dipped in 6.053×10-4mol/L ethanolic solution of [Ru(bpy)3]Cl2 for ten minutes, red fluorescence was observed under the UV light. The Silica-Ni-P composite coating can be excited by 469nm and has the maximal emission peak at 603nm, the response to oxygen shows that the coating has good response to dissolved oxygen and accords with Stern-Volmer equation. The sample coating has good repeatability and photostability. The support system offers a number of advantages over the other immobilization , such as silicone rubber, porous glass: (1) there are many exiguous pores in copper-screen, in which silica gel can be inlayed, so that sensitive materials can contact the oxygen fully. (2) the composite coating is tough, inert,and completely solid, so it can avoid the water vapour go into the support system, and the sensitive dye leach out; (3) its fluorescence can be efficiently quenched by O2.
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