Template-assisted Synthesis Of Noble Metals Composite Microspheres As SERS Substrate And Their Application In Detecting Of Pesticide Residue

In recent years, worsening environmental problems have aroused great concern. Among them, the heavyuse of pesticides has posed a serious threat to ecological environment and human health. Especiallypesticide residues in water, which can be enriched through the body, can not only cause chronic toxicityand "three-induced"(carcinogenic, teratogenic, mutagenic) effects, but also lead to endocrine disorders,reproductive and immune dysfunction, seriously threatening the human life and health. At present, ourcountry attaches great importance to excessive pesticide residues in water, for rapid detection of pesticideresidues imminent. Since the the found of Surface Enhanced Raman Scattering (SERS) effect of noblemetal nanostructure, as SERS signal of the analyte to provide a sample Raman "fingerprint" characteristicpeaks, highly sensitive detection and identification of other advantages, the noble metal nanostructurescontrol synthesis and SERS studies are of great concern. SERS effect on this topic in order to control thesynthesis of precious metals uniform microspheres with a focus on using template-assisted method weresynthesized gold (Au) and silica hollow microspheres@silver (SiO2@Ag) composite microspheres, and useits as SERS substrates for pesticide molecules (thiuram) conducted a preliminary exploration study. Themain results are as follows:(1) Based on electrochemical displacement reaction of metals, using uniform lead (Pb) colloidalmicrospheres as chemical template, polyvinylpyrrolidone (PVP) as the surfactant, the particles synthesizedby the control assembly into the hollow microspheres uniformly Au structure. Detailed parameters, such asPb colloidal microspheres, the amount of gold chloride acid and PVP impacts on the structure of Au hollowmicrospheres were explored. The formation mechanism of Au hollow spheres systematic studied; and R6Gand thiuram as detect objects on the Au hollow spheres to research its SERS performance.(2) Based on silica (SiO2) chemical properties, proposed SiO2spheres activation strategy, one-steptowards Ag shell colloidal spheres coated SiO2surface by hydrothermal method. The design idea is: thesurface of SiO2microspheres was activated and generate SiO-groups of the negatively charged while incontaining ammonia solution, positively charged silver enriched with ammonium ions, with the aid of PVP,on the surface of SiO2uniformly generated by the particles of Ag shell. Experiments confirmed the ideadesined is feasible. The experimental parameters such as the ratio of water/alcohol, affect the amount ofPVP, and the reaction time on the morphology of the sample to obtain a homogeneous SiO2@Ag compositemicrospheres detailed studied. To study the SERS performance of SiO2@Ag composite microspheres,thiuram and R6G used as detect objects. Initially realized the detection of thiuram reached lowconcentration of10-8M.