| Quantum dots (QDs) is a kind of inorganic semiconductor nanocrystals which is restricted in three-dimension to somewhat spherical shape. Compared with traditional fluorescent dyes and fluorescent proteins, QDs have excellent properties, such as broad excitation spectra, narrow and symmetric emission spectra and high quantum yield. QDs is one of the recent hot topics and have been extensively studied in biological labeling and imaging due to their unique optical properties. However, the study on chemiluminescence (CL) and electrogenerated chemiluminescence (ECL) of QDs is at early stage.CL has many prominent virtues such as high sensitivity, simplified optical setup and very low background signal. It will extend the application of QDs by studying the properties of CL and ECL of QDs. In this paper, a new method for CdSe QDs preparation in water solution was proposed, and CL and ECL of CdSe QDs have been studied. The main concents and results are listed as below:1. CdSe QDs were synthesized in aqueous solution using CdC12 and NaHSe as precursor and mercaptoacetic acid (MAA) as stabilizing agent, which were characterized by ultraviolet-visible (UV-vis) absorption spectra, fluorescence (FL) spectra and CL. The effects of reaction time, temperature, volume of MAA and the molar ratio of Cd:Se on the CL properties were also studied. The results showed that CdSe QDs were mono-dispersed with average size about 1.5 nm. Good CL signal of CdSe QDs can be observed when the ratio of Cd:Se at 2, the volume of MAA at 120μL, the temperature at 30℃and the reaction time at 1 h.2. A nevol CL system of CdSe QDs and hydrogen peroxide has been developed. Influences of some factors on the CdSe QDs CL intensity were investigated, including: the selection of oxidants, the concentration of base medium, the concentrations of oxidant and CdSe QDs, and several surfactants. It was found that hydrogen peroxide could oxidize CdSe QDs to produce CL emission in alkaline aqueous solution, and the cationic surfactant cetyl trimethylammonium bromide could enhance CL intensity to some extent. Furthermore, a possible CL mechanism of CdSe QDs was discussed. The present CL system would further exploit more applications of water-soluble CdSe QDs.3. ECL of water-soluble CdSe QDs in aqueous solution was developed. The ECL emission was observed by scanning CdSe QDs solution using a three-electrode system. Some influence factors such as scan rate, dissolved oxygen and QDs concentration were investigated in detail. Based on the inhibiting ECL of CdSe QDs by pyrogallol (1, 2, 3-trihydroxybenzene), a new method for pyrogallol determination was proposed. A linear relationship between ECL intensity and pyrogallol concentration was obtained in the range from 4.0×10-7 to 2.0×10-5 mol/L with a correlation coefficient of 0.9904. The limit of detection for pyrogallol was 6.6×10-8 mol/L (S/N = 3). A possible mechanism about ECL of QDs was also discussed. The experiment results showed that the ECL spectrum peak is similar to that of the defect FL spectrum peak, indicating the surface defects of QDs played a critical role in the ECL emission process.
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