Synthesis And Analytical Applications Of Novel Iridium Electrochemiluminescence Coordination Compound

ECL is a detection method which through the generation of an optical signal triggered by an electrochemical reaction, it has attracted extensive studies for its advantages like high sensitivity and wide linear range. The iridium complex and ruthenium tris(bipyridine) (Ru(bpy)₃²⁺) are the most extensively studied complexes. However, because the reaction takes place in solid-liquid interface, it consumes more reagent than other methods. Furthermore, these reagents are very expensive, This disadvantage continue to bring high-cost analysis and restrict its application. Therefore, the ECL reagent immobilized which can not only overcome those problems, but also simplify the device cause great interest. Take Ru(bpy)₃²⁺ for instance, it has been immobilized in Langmuir–Blodgget films, self-assembled films, polymer films, sol–gel composites. But most ruthenium complexes are water soluble, sensitive and the detection limits obtained by these ruthenium derivatives are not satisfactory. Due to metal iridium complexes and bipyridine ruthenium complex is similar to the ground, excited state Eh, and most iridium complexes are insoluble in water, iridium complexes have been studied intensively recently. Moreover, the research and applications of solid-state Electrochemiluminescence of iridium complexes is most important.Iridium complexes also have excellent ECL response to amines, however, most amines are exist in mixture. For this reason, amines can not be detected directly by ECL, it restricts the application of ECL. Molecularly imprinting technique is the way which get through the sol-gel process to lead the target molecules up to inorganic network structure, after the template is removed from the insoluble network materials, sites which are complementary to the template are left. Therefore, amines can be detected directly through the way which coupled with ECL and MIT, the study of MIT will be the key to achieve this aim.The main results were given as follows:1. Synthesized a novel iridium coordination compound--(pq)₂Ir(N-phMA). The properties like electrochemical natrue in liquid phase and solid phase, UV-Vis absorption spectroscopy, fluorescence spectrum and ECL were researched.2. The polymerization of (pq)₂Ir(N-phMA) and styrene, (pq)₂Ir(N-phMA) and PVA-SbQ were obtained, ECL of polymerization was also studied. Constructed the multi-walled carbon nanotubes/Ployvinyl alcohol/(pq)₂Ir(N-phMA) modified electrode. Steady ECL of (pq)₂Ir(N-phMA) solid phased was obtained. It was found that melamine can be sensitively detected as a coreactant in the ECL reaction of (pq)₂Ir(N-phMA). The equation of linear regression was mensurated when melamine detected by this modified carbon electrode. The ECL show a good liner relationship to lgC at the range of 1.0×10^-3～1.0×10^-6 mol/L when melamine act as coreactant. The equation of linear regression was y=64.78lgC+410.26(R = 0.9953), the limit of detection achieved 10^-9 mol/L. Another modified carbon electrode of (pq)₂Ir(N-phMA) was constructed through voltolization. Effect of different electrodes, different number of circle and pH on modified carbon electrode were compared, so did the electrodes before and after voltolization. The possiblely mechanization of voltolization was speculated.3. Based on sol-gel molecular imprinting technology, a sensitive and selective electrochemical method for the direct determination of melamine in complex matrix was developed. The recovery of melamine achieved 97.50%～103.30%, The equation of linear regression was i=10.78lgc+99.76(R=0.9973) at the range of 1.0×10^-3～1.0×10^-6 mol/L.The experiment conditions were optimized. The electrochemical behavior of melamine was initially studied, and a possible oxidation mechanism was proposed.