Construction Of Bimetallic-nanoclusters Ratio Fluorescent Probe And Its Analytical Application

Gold-silver nanoclusters?AuAgNCs?have the advantages of strong photostability,good biocompatibility,and strong catalytic activity,etc.,and have great application potential in analytical detection.The ratio fluorescence sensor has the characteristics of good selectivity,high sensitivity and simple operation.Based on AuAgNCs,a ratio-based fluorescence probe was constructed for the fluorescence sensing of thioacetamide?TAA?and hypoxanthine?Hx?.The main contents of the thesis include:?1?Gold and silver nanoclusters?AuAgNCs@GSH?with double fluorescence emission were synthesized by using Glutathione?GSH?as template and ascorbic acid as reductant at 80°C in water bath.When the excitation wavelength is 360 nm,the fluorescence emission peak lies at 440 nm and 650 nm.The effects of synthesis time and acidity on AuAgNCs@GSH were investigated.The results showed that the fluorescence intensity at 440 nm and 650 nm increased with the increase of water bath time,but the fluorescence intensity at 650 nm kept increasing after 4 hours.It was characterized by fluorescence Spectra,high power transmission electron microscopy,X-ray photoelectron spectroscopy and X-ray diffraction.?2?AuAgNCs@GSH,which was synthesized in water bath for 30 minutes,was used as a ratio fluorescence probe for the determination of TAA.In the presence of TAA,the fluorescence peak at 650 nm shifted to 700 nm,and the fluorescence intensity of the peak increased with the increase of TAA content,the fluorescence intensity of the probe at 440 nm was almost constant.A new method for the determination of TAA by the AuAgNCs@GSH ratio fluorimetry was established.Under the optimal conditions,the linear range of TAA determined by F₇₀₀/F₄₄₀40 is 0.5to 55?M,the detection limit is 0.19?M?3?/S,n=8?.The method has been applied to the determination of real samples,and the recovery rate is between 98.2%and107.2%.Compared with other analytical methods of TAA,AuAgNCs@GSH ratio fluorimetry has wider linear range,lower detection limit and higher sensitivity.?3?AuAgNCs@GSH,which was synthesized in water bath for 4 hours,was used as a ratio fluorescence probe for Hx determination.The results show that the fluorescence intensity at 440 nm increases and the fluorescence at 650 nm decreases with the increase of Hx content.Under the optimal conditions,the linear range of Hx measured by the ratio of fluorescence intensity at 440 nm to 650 nm(F₄₄₀/F₆₅₀)is 0.5to 10?M,and the detection limit of the method is 0.055?M?3?/S,n=8?.The method has been applied to the determination of real samples,and the recovery rate is between 98.43%and 104.05%.