Establishment Luminescence Sensors For Some Antibacterial Drugs Based On Type Cdte Quantum Dots

In this paper, glutathione (GSH) capped type CdTe quantum dots (GSH-CdTe QDs), CdTe/CdS quantum dots (GSH-CdTe/CdS QDs) and thioglycolic acid (TGA) capped CdTe/CdS quantum dots (GSH-CdTe/CdS QDs) in aqueous solution. The prepared QDs were characterized by using fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), fluorescence microscope (FM), X-ray powder diffraction (XRD), ultraviolet-visible (UV-vis) absorption and fluorescence spectrometry. The interactions of type CdTe QDs with ellagic acid, benzophenanthridine alkaloids (sanguinarine and chelerythrine) and polymyxin B sulfate were studied by UV-vis absorption, fluorescence and resonance Rayleigh scattering (RRS) spectra. Based on this, the luminescence sensors for ellagic acid, benzophenanthridine alkaloids (sanguinarine and chelerythrine) and polymyxin B sulfate were established based on type CdTe quantum dots. The main work of this thesis is as follows:1Establishment fluorescence sensor for ellagic acid based on glutathione capped CdTe quantum dotsA sensitive and simple method for the determination of ellagic acid (EA) was developed based on the fluorescence quenching effect of EA for glutathione (GSH)-capped CdTe quantum dots (QDs). Under optimum conditions, a good linear relationship was obtained from0.3118to55.0μg·mL-1with correlation coefficient of0.9983, and the detection limit (3σ/K) was0.0936μg·mL-1. The fluorescence quenching mechanism has been proposed on the basis of electron transfer supported by ultraviolet-visible (UV-vis) absorption, fluorescence spectroscopy and the measurement of fluorescence lifetime. The method has been applied to the determination of EA in synthetic samples and fresh urine samples of healthy human with satisfactory results. The proposed method manifested several advantages such as high sensitivity, short analysis time, low cost and ease of operation.2Establishment fluorescence sensor for benzophenanthridine alkaloids based on glutathione capped CdTe/CdS quantum dotsWater-soluble glutathione (GSH)-capped core/shell CdTe/CdS quantum dots (QDs) were synthesized. In pH5.4PBS buffer medium, the interaction between GSH-CdTe/CdS QDs and benzophenanthridine alkaloids (sanguinarine (SA) and chelerythrine (CHE)) was investigated by fluorescence spectroscopy, UV-vis absorption spectroscopy and electrochemical technique. Addition of SA/CHE to GSH-CdTe/CdS QDs results in fluorescence quenching of GSH-CdTe/CdS QDs has been observed. Quenching intensity was in proportional to the concentration of SA/CHE in a certain range. For SA, the linear relationship was obtained from0.011to40μg·mL-1, and the detection limit (3σ/K) was3.4ng·mL-1. For CHE, the linear relationship was obtained from0.073to24μg·mL-1, and the detection limit (3σ/K) was21.9ng·mL-1. Based on the quenching of the fluorescence of GSH-CdTe/CdS QDs by SA/CHE, a novel, simple, rapid and specific fluorescence sensor for SA/CHE was proposed. The fluorescence sensor has been applied to the determination of SA/CHE in fresh urine samples of healthy human with satisfactory results.3Sensitive detection of polymyxin B sulfate using enhanced resonance scattering signals and decreased fluorescence signals with CdTe/CdS quantum dots as probeThioglycolic acid-capped (TGA-capped) CdTe/CdS quantum dots (QDs) were prepared in the water phase. The interaction of TGA-CdTe/CdS QDs with Polymyxin B sulfate (POBS) was investigated by ultraviolet-visible (UV-vis) absorption, fluorescence, resonance Rayleigh scattering (RRS) spectroscopy and the measurement of fluorescence lifetime. Under optimum conditions, not only the UV-vis absorption and fluorescence spectra were changed, but also the RRS intensity was greatly enhanced. These phenomena offered useful techniques for the determination of POBS with fluorescence quenching and RRS methods. The linear ranges and detection limits of POBS were0.09～5.25μg·mL-1and27.5ng·mL-1for the fluorescence quenching technique,0.02～6.0ng·mL-1and6.36ng·mL-1for the RRS technique. Among them, the RRS approach obtained the higher sensitivity. Accordingly, a novel rapid, convenient, and highly sensitive RRS method for the determination of POBS was proposed and applied to detect POBS in pharmaceutical preparations with satisfactory results. Furthermore, the suitable reaction conditions, affecting factors as well as the influence of coexisting substances were studied. Some possible reaction mechanisms were also discussed.