Study On The Synthesis Of Carbon Dots And Spectroscopy Analysis Of Natural Small Molecule Pharmaceuticals

Carbon dots as a new fluorescent carbon nanomaterial has many advantages, such as tunable excitation and emission wavelengths, resistant to photobleaching, good light stability, no light flickering fluorescent properties, which made it have good potential applications in biochemical analysis, cell imaging, pharmaceutical analysis and other areas. Resonance light scattering technique because of its simple and fast operation, high sensitivity has been widely used in many fields, such as life science, pharmaceutical analysis. In this paper, a highly sensitive method for the determination of Palmatine has been established. Moreover, we explored a new low-temperature rapid synthesis of carbon dots with high quantum yields, and studied its applications in pharmaceutical analysis. The main aspects are as follow:(1) Study on the RLS spectrum of PaH and Morin. At pH4.6HAc-NaAc buffer medium, ion-association complex occurs because of the interaction of Palmatine Hydrochloride (PaH) with morin and results the enhanced resonance light scattering signals at290nm. The enhanced RLS signals is proportional to the concentration of PaH in a range of0.08～1.0umol/L. According to this, a novel RLS detection method for PaH is established. The limit of detection is8.0nmol/L. The reaction mechanism, pH, ionic strength and interference of foreign substances were also studied. This method was successfully applied for the determination of PaH in tablets and capsule with relative standard deviation (RSD)<3.3%.(2) A one-step low-temperature hydrothermal synthesis of carbon dots with highly fluorescent quantum yields. One-step hydrothermal synthesis of highly luminescent carbon dots used citric acid as carbon source and polyethyleneimine as passivation. The synthesis method is simple, economical and environmental friendly. The obtained Carbon dots have upconversion fluorescence properties with fluorescence quantum yields of up to53%. Study particle size, luminescent properties and interference ability of carbon dots. It is found that the particle size of the carbon dots is around4nm and has good water solubility, light stability and biocompatibility. The experiment shows that the carbon dots is sensitive to pH, it will be applied to pH sensing.(3) Study the fluorescent spectrum of the interaction of carbon dots and small molecule natural morin. At pH4.0HAc-NaAc conditions, carbon dots with a large number of amino on the surface interact with negatively charged Morin by the action of electrostatic forces, which result in the quenching of fluorescence signals located at449nm and upconversion fluorescence signals located at451nm. The reduced fluorescence intensity is proportional to the concentration of morin in the range of0～300μmol/L. The limit of detection is0.6μmol/L. A double fluorescence quantitative detection method of Morin is established. Experiment discussed the reaction conditions and the interference of foreign substances. The established method successfully applied to testing Morin content in urine with the recovery of96.2～104.6%, relative standard deviation (RSD)≤4.5%.