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The Study On The Application Of Nanoparticles In Metal Ions And The Small Molecule Analysis

Posted on:2011-11-14Degree:MasterType:Thesis
Country:ChinaCandidate:Z H QinFull Text:PDF
GTID:2121360302997985Subject:Analytical Chemistry
Abstract/Summary:PDF Full Text Request
Because of the good electrical properties, optical properties, magnetism and so on, metal nanoparticles have been widely applied in the fields of environment, material, medicine, biology, etc. Although these applications in the methods have good sensitivity and selectivity, they are cost- and time-consuming and need espensive instrument. In this dissertation, we develop two simple and rapid methods utilizing the especial interaction of gold nanoparticles (Au-NPs) or silver nanoparticles(Ag-NPs) with metal ions and the other small molecule, based on the investigation of many literatures. Meanwhile, the synthesis of Ag-NPs in soluble starch solution and their applications were studied. The main contents are as follows:(1) Au-NPs self-assembled and formed a network structure. At pH 5.33, citrate-capped Au-NPs which displayed negative charge could react with melamine through electrostatic interactions and self-assemble to form a network structure. Therefore, a new absorption peak at approximately 700nm was appeared and its intensity enhanced following with the concretion of melamine. The enhanced absorption intensity (AA) at 700nm was linear with the concentration of melamine over the range of 0.03-0.3μg·mL-1. This method could be used to detect synthetic samples, and the recovery was larger than 95%.(2) A new method of detecting mercury ions have been developed in this contribution with Ag-NPs. When mercury ions were added into the Ag-NPs solution, the solution displayed color change rapidly and blue-shift in the maximum absorption wavelength. Furthermore, the blue-shift was in proportion to the mercury concentration in the range of 2.0×10-7-6.0×10-6mol·L-1. Therefore, we proposed a highly rapid, simple and selective method for mercury, with a detection limit (3σ/κ) of 6.6 nM.(3) In this essay, the synthetic method of Ag-NPs in soluble starch solution and their applications were studied. The different concentrations of Ag-NPs solution were prepared in the 1% soluble starch solution, which using Sodium citrate as reducing agent to reduce the silver nitrate solution. We studied out that this kind of Ag-NPs could have special respond to hydrogen peroxide, and this phenomenon in the Ag-NPs solution of 2mM concentration was very notable.
Keywords/Search Tags:Au-NPs, melamine, Ag-NPs, blue-shift, soluble starch
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