Quantification of Functional Groups on Self-Assembled Monolayers

• Main Authors: LIU, WAN-CHUN, 劉婉君
• Other Authors: Chau, Lai-Kwan
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/03330135748177677730

碩士 === 國立中正大學 === 化學暨生物化學研究所 === 103 === Functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical or physical reactions of those molecules. Commonly, a functional group can link to a specific molecule by covalent bonding, such as thiol to noble metal. Also, some functional groups allow conjugation of peptides, proteins, antibodies, or DNA to a surface. Since the chemical characteristics of a surface are dependent on the surface density of a functional group, the characterization and quantification of functional groups on surfaces is therefore highly important. Thiol is a common functional group which is widely used in analytical chemistry. There are a number of ways to quantify the number of thiol in liquid or sol-gel, for instances, high-performance liquid chromatography (HPLC), electro-chemical analysis, capillary electrophoresis (CE), mass spectrometry (MS) and fluorescence spectrometry. However, there have been a few investigations about the quantification of the surface density of thiol on solid substrates. Therefore, a method to quantify the surface density of thiol group on substrates for biosensors, including surfaces devised from (3-Mercaptopropyl)trimethoxy-silane (MPTMS), (3-Mercaptopropyl)methyldimethoxysilane (MPDMS) and Mercaptopropyl-silatrane (MPS) was proposed and investigated. In this work, we have successfully used the Ellman’s reagent and UV/VIS absorption spectroscopy to quantify the coverage of thiol group on glass substrates modified by the three different mercaptosilanes. Futhermore, we have used Toluidine Blue O (TBO) to quantify the carboxylic acid (－COOH) functional group of a mixed self-assembled monolayer (SAM), 11-Mercapto-undecanoic acid (MUA) and 6-mercapto-1-hexanol (MCH), on gold nanoparticle surface, by UV/VIS absorption spectroscopy and infrared spectroscopy.