Synthesis Of Gold And Silica Nanoparticles And Their Applications In The Detection Of Pharmaceutical And Environmental Samples

Drugs and the environment are related to people’s health and safety,improper usage of drugs and environmental pollution will do great harm to people’s life and health.So it is very important to detect drugs and environmental pollutants.The reported determination methods for drugs and environmental pollutants mainly include electrochemical method,high performance liquid chromatography,optical analysis and others,among those,fluorescence analysis is widely used for it is simple and sensitive.These reported methods have advantages of a high sensitivity or low detective limits etc,mean while some of them are also have problems such as unstability or inconvenience in operation,therefore,it is important to develop new detection methods.With the development of nanomaterials,many nanomaterials are used in fluorescence analysis in recent years and have greatly enhanced the application range and detection capability of fluorescence analysis.Among those nanomaterials,gold and silica nanoparticles are widely used for their unique optical properties and the excellent biocompatibility.Based on these,gold and functional porous silica nanoparticle were synthesized and used in fluorescence analysis in our work.On one hand,based on the fluorescence quenching of gold nanoparticles,methods for the determination of thiol-based tablets with label-free gold were established;on the other hand,functional porous fluorescence silica nanoparticles were prepared and used for environmental sample analysis for increase the detection sensitivity of fluorescence analysis.The main work is as follows:1.Synthesis of gold nanoparticles and its application in drug analysisGold nanoparticles were synthesized by sodium citrate reduction method and characterized by transmission electron microscopy and ultraviolet-visible absorption spectroscopy.The results showed that the synthesized gold nanoparticles are spherical particles in a single dispersed state,with a size of 13 nm,an absorption peak of about 520nm,which are consistent with the literature reporte.Based on the effect of AuNPs fluorescence resonance energy transfer on fluorescence quenching of rhodamine B（RhB）and the difference of fluorescence quenching ability of AuNPs with different sizes,a fluorescence analysis method for the rapid determination of methimazole in tablets was established.Under the selected conditions,the concentration of methimazole has a good linear relationship with the fluorescence change value of the system within the range 4.4×10^–88.8×10^–6mol/L with the correlation coefficient was 0.999,and the detection limit（3s/k）was 3.3×10^–88 mol/L.The method has been applied to the determination of methimazole tablets with a recovery of 96.7%⁹9.2%.Based on the enhancement of fluorescence signal of the AuNPs-calcein system by adding penicillamine,a quantitative method for the determination of penicillamine was established and the determination mechanism was explored.The results showed that the system had a good liner relationship between fluorescence recovery value and the concentration of penicillamine,and the recovery was 98.8%¹02.4%.2.Preparation of fluorescent silica nanoparticles and its application in environment analysisIn this work,functional porous silica nanoparticles（SiO₂）with chitosan as template were synthesized with inverse microemulsion method,then Rhodamine B were loaded to the nanoparticle for prepare the functional fluoresce silica nanoparticles.The prepared nanoparticles were characterized by fluorescence spectroscopy,transmission electron microscopy,and fourier transform infrared spectroscopy.The results showed that the size of the synthesized nanoparticles ranges from 50 to 60 nm,the Chitosan/SiO₂nanoparticles have porous structure and RhB/Chitosan/SiO₂ nanoparticles have the same fluorescent properties with Rhodamine B.Based on the fluorescence quenching effect of Cu²⁺on RhB/Chitosan/SiO₂fluorescent nanoparticles,a fluorescence analysis method for the quantitative determination of Cu²⁺was established.The determination mechanism was discussed and the experimental conditions were optimized.Under the optimum conditions,the fluorescence quenching value of the system is linearly correlated with the concentration of Cu²⁺in the range 2.4×10^–72.5×10^–5mol/L with the detection limit（3s/k）of 2.2×10^–7mol/L and the recovery of 96.9%¹03.7%.Based on the interaction between RhB/Chitosan/SiO₂ fluorescent nanoparticles and picricacid,a quantitative method for the determination of picricacid was established,and the experimental mechanism was discussed.The results showed that the linear range of the method was 5.0×10^–66.0×10^–4mol/L,the correlation coefficient was 0.999,and the detection limit（3s/k）was 3.0×10^–66 mol/L.