HEPES-Au NPs-assisted growth of Au nanostructures for sensing Hg(II) ions

• Main Authors: Yang,Pei-Chia, 楊珮佳
• Other Authors: Lin,Yang-Wei
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/b328az

碩士 === 國立彰化師範大學 === 化學系 === 107 === In this study, Hg(II) label-free colorimetric nanosensor was researched and developed by using Hg(II) versus the growth of gold nanoparticles (Au NPs) obstruction and integrated Surface-Enhanced Raman Scattering (SERS) for further determination. The study of the effect of Au NPs on the Raman signal strength of 4-Mercaptobenzoic acid (4-MBA) probe molecules in SERS signals for different concentrations of Hg(II). Under optimal conditions, Ultraviolet-visible spectroscopy (UV-Vis) can be used to detect the Hg(II) concentration range of 10 nM~100 μM with a detection limit of 7 nM, showing good selectivity and sensitivity for Hg(II) test. The electric field of SERS on the rough metal surface enhances the Localized Surface Plasmon Resonance (LSPR) that occurs. The effect of enhancing the SERS signal depends on the size, shape and aggregation of the nanoparticles. If the metal nanoparticles have a larger size, the absorption peak will move toward the longer wavelength region, which may produce a stronger LSPR at 1590 cm-1 under Laser excitation. Under optimized conditions, this study was provided with detecting a linear range of Hg(II) from 0.1 nM to 1.0 μM with a detection limit of 0.06 nM. The results of this study show the possibility of quantitative analysis of different Hg(II) concentrations using the developed method. With SERS activity of the Au NPs were modified by 4-MBA, no matter the sensitivity or on the detection limitation was with better effect while in comparison with the UV-Vis absorption spectrum, and the detection limitation of SERS was nearly 100 times more than that of UV-Vis. In addition, the SERS test was conducted by using hydrophobic test paper in comparison with the test paper without the hydrophobic field, the Au NPs were concentrated in the center of the test paper. This not only controls the distribution range of the Au NPs, to make the distribution density uniformly but also makes the signal peak more stable, to expand the range of spectral integral area values for better sensitivity. Finally, in the application of real water samples, the measurements of UV-Vis and SERS are 64~126% and 75~117%, respectively, and both are with good recovery percentage. In the future, we hope to further study this material, improve the detection sensitivity of Hg(II), and extend it to the aspects of bio-imaging, drug carriers and antibacterial experiments, and use its advantages to develop more comprehensive applications.