Study On Electrochemiluminescence Of Water-soluble Fluorescence Nanoparticles And Its Analytical Application

Electrogenerated chemiluminescence (ECL) has become an important and valuable detection method in analytical chemistry in recent years. In order to meet the needs of actual detecting, studing of new ECL reagents and establishing of new ECL system had been the hotspot of ECL research. Semiconductor nanomaterials are of considerable interest owing to their outstanding characteristics. Since 2002, Bard and coworkers pioneer a new field for study the ECL by mix ECL and semiconductor nanomaterials. Based on the above background, this work studied the ECL of CdTe quantum dots (QDs), ZnSe QDs and carbon dots (CNCs) and its analytical application. The main concents and results are listed as below:1. Water-soluble CdTe QDs was prepared in ambient atmospheric conditions with one-step synthetic route. The ECL behavior of CdTe QDs was investigated, and a novel method of detection of Hg2+ was also developed. In the optimized condition, the concentration of Hg2+ showed good linear relationship with the ECL intensity of ZnSe QDs at the range of 1.17×10-8～3.55×10-7 mol/L. The mentioned method showed good reproducibility and selectivity, and it was applied to the determination of Hg2+ in crude salt and refined salt with satisfactory results. As a result, the QDs ECL analysis is of great applicable value.2. Water-soluble ZnSe QDs with the property of blue-emitting and low-toxicity were prepared. The ECL of the as-prepared ZnSe QDs as well as its mechanism was also investigated. It was found that the NaOH can enhance the ECL intensity, which suggested that the surface state of ZnSe QDs must be changed and a covering of Zn(OH)2 was formed. In addition, the ECL intensity was greatly enhanced in the presence of H2O2, and the dynamic range is from 6.10×10-7～3.12×10-4 mol/L H2O2. On this basis, we developed a novel method detecting H2O2, and the detection limit (at S/N=3) is 2.00×10-7 mol/L. This method showed a good reproducibility and selectivity. As a novel biosensor, it was used to detect H2O2 in the pig kidney (pk-15) cell, vero cell and mineral water, respectively. As a novel ECL biosensor, ECL of ZnSe QDs was used to detect H2O2 in pk-15 cell, vero cell and mineral water sample and showed a satisfactory result.3. Water-soluble CNCs was prepared by electrochemical oxidation of graphite. The ECL behavior of CNCs was investigated using glass carbon electrode, Au electrode, ITO electrode and Pt electrode. In addition, the effect of K2S2O8, a coreactant commonly used in ECL systems, was also investigated. It was found that K2S2O8 could enhance the ECL intensity of CNCs. Further more, glassy carbon electrode was modified with the water-soluble CNCs successfully, and its potential application was discussed.