Study On The Application Of Resonance Rayleigh Scattering Spectra In Polysaccharide Analysis With Quantum Dots As Probes

Quantum dots (QDs), which are semiconductor nanoparticles that have all three dimensions confined to the 1-10 nm length scale, have attracted considerable attention because of their unique luminescent properties. QDs have been applied to the detection of biomacromolecules, metal ions, pharmaceuticals, and so on. Therefore, it is significant for further developing new analytical application of QDs.Resonance Rayleigh scattering (RRS) technology was developed during 1990s. As a newly analytical technique, it has been received much attention because of its sensitivity and simplicity Therefore, this technique has been increasingly applied to the determination of macromolecules such as inorganic ions, organic compounds, nucleic acids, proteins, cationic surfactant, and some drugs. In recent years, this technique was applied to study nanometer particle. However, QDs were used as probes for the determination of polysaccharides by resonance Rayleigh scattering has few reports.This paper contained two parts. The first part was the literature review and it includse the preparation and application of quantum dots, the development of resonance Rayleigh scattering technology and the introduction of polysaccharides in common analysis. The second part was research paper. In this paper, quantum dots were used as probes for the determination of two proteoglycans by resonance Rayleigh scattering method.Determination of Dermatan Sulfate:1. Resonance Rayleigh scattering method for the determination of Dermatan Sulfate with CdSe quantum dots as probesThe CdSe quantum dots capped by 2-mercaptoethylamine hydrochloride with an average diameter of 2 rm were synthesized in water solution. It could react with dermatan sulfate (DS) and form the large aggregates by virtue of electrostatic attraction and the hydrophobic force, which induced a great enhancement of RRS. In a certain ranges, the enhancements of scattering intensity (ΔI) were directly proportional to the concentration of DS. This method revealed good sensitiviy, and the detection limit (38) was 1.3 ng mL-1. The optimum conditions of this reaction system and the influencing factors were investigated. In addition, ultraviolet absorption spectra and transmission electron microscope were employed to discuss the reaction mechanism of RRS enhancement. A novel method for the determination of trace DS using CdSe quantum dots probes was developed.2. Resonance Rayleigh scattering spectra of CdTe QDs-DS system and its analytical applicationThe CdTe quantum dots capped by 2-mercaptoethylamine hydrochloride was synthesized in water solution. CdTe QDs can react with dermatan sulfate and form an ion association complex. The linear relactionship between the relative intensity ofΔIRRS and concentration of DS was in the range of 0.2-0.6μg mL-1. A sensitive, simple, and selective method for the determination of DS with CdTe QDs as probe by resonance Rayleigh scattering technique was developed. The optimum conditions and the influence factors were investigated. Moreover, the composition of ion-association complexes and the reaction mechanism were discussed. The method was applied to the determination of DS in human blood with satisfactory results.Determination of Dextran Sulfate Sodium:1. Resonance Rayleigh scattering method for the determination of dermatan sulfate sodium with water solubility CdSe quantum dots as probeIn acetic acid-sodium acetate buffer medium, the surface of QDs was assembled by 2-mercaptoethylamine hydrochloride which showed positive charge. The CdSe QDs could react with dextran sulfate sodium (DSS) and form the large aggregates by virtue of electrostatic attraction and the hydrophobic force, which leads to the remarkable enhancement of RRS. The maximum scattering peak was located at 343 nm. A sensitive and simple method for the determination of DSS with CdSe QDs as probes by resonance Rayleigh scattering technique was developed. The optimum conditions and influence factors of the reactions were investigated. It has been applied to the determination of DSS in human blood and urine samples and this method exhibited satisfactory results.2. Resonance Rayleigh scattering spectra of CdTe QDs-DSS system and its analytical application2-Mercaptoethylamine hydrochloride capped CdTe quantum dots with the diameter of 2-3 nm were synthesized in aqueous solution. At pH 5.0, CdTe QDs could react with DSS and form the large aggregates by electrostatic attraction and the hydrophobic force, which resulted in a great enhancement of resonance Rayleigh scattering. In this paper, the relationship between ultraviolet-visible absorption and resonance Rayleigh scattering was studied. The affecting factors and characteristics of RRS for the interaction of CdTe QDs with DSS were also investigated and a sensitive, simple and fast method for the determination of trace amounts of DSS using the RRS method was developed. It has been applied to the determination of DSS in human blood and urine samples with satisfactory results.