Study On The Synthesis Of Fluorescence Carbon Dots And The Applications In Biochemical And Environment Analysis

Carbon dots (CDs) is a new fluorescence carbon nanomaterial, which possesses upconversion and quantum size effects. With the unique optical properties it has been widely investigated and applied in the fields of chemistry and biology sensors, bioimaging, environment detection, and so on. In this dissertation, we mainly describe the preparation and application of CDs. We explore one new route to synthesize fluorescent carbon dots by convenient and fast method, and study the application of the CDs for biochemistry and environment detection. The main contents are as follows:(1) One-step ultrasonic systhesis fluorescent Carbon dots and its bioimaging application. The fluorescent carbon dots (CDs) was facilely synthesized from candle soot by a one-step violet acid assisted ultrasonic treatment with average diameter less than 10 nm. Compared with traditional fluorescent dyes and Quantum dots (QDs), the as-prepared CDs not only had excellent yellow to orange photoluminescent properties, but also it was effective fluorescent reagent for bioimaging due to its anti-photobleaching, low cytotoxicity and biocompatibility. Moreover, the fluorescence intensity of the CDs was responsive to pH value under acidic conditions, suggesting a potential pH sensor.(2) Quantitative determination of fluoride with a composite fluorescent probe of carboxylate carbon dots-aluminum(Ⅲ). Carboxyl-carbon dots (CDs) were prepared and used to construct a composite fluorescent probe of CDs-aluminum(Ⅲ) based on coordination between carboxy groups and aluminum(Ⅲ). The probe was used to quantitatively detect fluoride ions (F-) in environmental samples by exploiting the competition between F- and carboxy groups on the CDs for Al3+. It was found that Al3+ coordinated with the carboxylate groups on the surface of CDs, inducing aggregation and fluorescence quenching. F- coordinates more strongly with Al3+ than the CDs, which causes the aggregation of CDs to dissociate, allowing recovery of fluorescence. The increasing fluorescence of the CDs gave a novel method for quantitatively detecting F- in the linear range of 4.0×10-5～6.0×10-3 mol/L. This method could be applied for simple and rapid determination of F- in waste water from glassworks, with recovery of 93%～106%, and relative standard deviation of less than 7.6%.(3) The research is about the energy transfer between the fluorescence carbon dots and Au nanoparticles. In the article, we firstly study the energy transfer between the two different nanoparticles by using fluorescence carbon dots as energy donor and Au nanoparticles as acceptor. The the composite fluorescence probe was designed by Au nanoparticles and fluorescence carbon dots. Owing to the specific interaction between the Au nanoparticles and the sulphur of the mercaptopurine, we established a method for quantitatively mercaptopurine detection. The liner range of the method is 5.0×10-6～6.0×10-5 mol/L with the correlation coefficient of 0.9906.