Preparation Of Functionalized Nano-gold / Silver And Research In Colorimetric Analysis

Nanoparticles,1¹00nm particles, possess very unique physical, chemical,andbiological properties, becoming a hotspot of research in the recent years. Silvernanoparticles （AgNPs） and gold nanoparticles （AuNPs） show different colors whendesperations and aggregation, owing to the surface plasmon resonance （SPR） ofnoble mental nanoparticles. The color is changed by the aggregation of AuNPs orAgNPs functionlized with organic molecules, which can be effect with particularsubstance. AuNPs and AgNPs are widely used in the colorimetric detection based onthis principal. In this article, it was explored that not only the preparation of nakedAuNPs and AgNPs, but also the response between colorimetric sensor anddeterminand, including mental ions and amino acid. There were many advantages inthe colorimetric detection, such as simple manipulation, speediness, andvisualization.I. Colorimetric detection to Cr3+by Tartaric acid-covered silvernanoparticles.Tartaric Acid （TA） was covered on the surface of silver nanoparticles, inorder to synthesis a small TA-AgNPs colorimetric sensor. In the same condition, thecolor change of TA-AgNPs was used to assay15different metal ions. There was anobvious response only to Cr3+without disturbance by the other mental ions, whenthe acidity of solution was in the vicinity of pH8.0. Moreover, there was goodrelationship between A502/A393and the concentration of Cr3+in the range of0.10¹.36μM. The minimum detected concentration by naked eye was0.20μM. Thismethod possessed a lot of advantages such as simple, inexpensive, high selectivity,visualized and so on. It can be used the swift detection in the actual water sample.II.Colorimetric detection to cystein by silver nanoparticles stabilized with tartaric acid.There is a response between AgNPs and cystein （Cys） in acidic condition. It wasreported that AuNPs had been used to detect Cys in acidic solution, but for AgNPs,the stability of method was not as good as expected. So we used TA as stabilizer andacidifier, providing a swift and inexpensive method of colorimetric detection to Cys.The minimum detected concentration by naked eye was located as0.10μM, and theliner range between A518/A394and the concentration of Cys was about0.10⁰.98 μM.III. Colorimetric detection to Pb²⁺ by thiobarbituric acid-modified goldnanoparticles in the presence of glycine. The TBA-Gly-AuNPs colorimetric sensor wasmade by addition of glycine （Gly） and thiobarbituric acid（TBA）into the AuNPssolution. There was an obvious response to Pb²⁺, when the acidy was in the vicinityof pH10.0, and14different kinds of mental ions solution was tested. The A600/A518presented a good linear relationship with Pb2+concentration ranged from6.90to22.90μM, and the minimum detected concentration by naked eyes was located as6.90μM. This method was expected to be used for actual sample analysis.