Abstract

Plasmonic nanoparticles functionalized by organic molecules appear to be a promising approach for developing detection systems for effective, simple, sensitive, selective, and cost-effective colorimetry and surface-enhanced Raman scattering (SERS) agents to generate characteristic color patterns and spectral fingerprints of metal ions for their identification and quantification in aqueous solution. In order to achieve this goal, silver nanoparticles functionalized with lignin(L-AgNPs) were synthesized by a microwave-assisted method and used for the determination of Co(II), Cr(III), and Mn(II) in aqueous solution using colorimetry and SERS. In the presence of the L-AgNPs colloidal solution, water samples containing Mn(II) ions turn black, while those containing Cr(III) ions become reddish brown. Moreover, in water samples with Co(II) ions, the addition of L-AgNPs solution leads to formation of a brown precipitate and the water samples become transparent. The ultraviolet-visible spectra of the Co(II)-, Cr(III)-, and Mn(II)-spiked water mixed with L-AgNPs colloidal solution show that these metal ions modify the localized surface plasmon resonance (LSPR) band of L-AgNPs which is caused by the aggregation induced by metal ions in the colloidal solution. The potential of the synthesized L-AgNPs colloidal solution has also been explored for SERS measurements of the metal ions. In the presence of L-AgNPs, significant enhancement in the Raman signal is observed for Mn(II) which is not seen in case of other metal ions showing its selectivity for this ion. The study is helpful in conceptualizing, designing, and fabricating nanoparticles for colorimetry- and SERS-based devices for metal sensing applications.

摘要

通过有机分子功能化的等离子体纳米颗粒似乎是开发检测系统的有效方法，该检测系统可用于有效，简单，灵敏，选择性和具有成本效益的比色法和表面增强拉曼散射（SERS）试剂，以产生金属的特征颜色图案和光谱指纹离子用于水溶液中的鉴定和定量。为了实现这一目标，通过微波辅助方法合成了用木质素（L-AgNPs）功能化的银纳米颗粒，并将其用于测定水溶液中的Co（II），Cr（III）和Mn（II）。比色法和SERS。在存在L-AgNPs胶体溶液的情况下，含有Mn（II）离子的水样品会变成黑色，而含有Cr（III）离子的水样品会变成红棕色。此外，在含有Co（II）离子的水样品中，L-AgNPs溶液的添加导致形成棕色沉淀，水样变为透明。掺有L-AgNPs胶体溶液的掺Co（II）-，Cr（III）-和Mn（II）的水的紫外-可见光谱表明，这些金属离子修饰了L-AgNPs的局部表面等离振子共振（LSPR）谱带。 L-AgNPs是由胶体溶液中金属离子诱导的聚集引起的。还已经探索了合成的L-AgNPs胶体溶液的潜力，用于金属离子的SERS测量。在存在L-AgNP的情况下，观察到Mn（II）的拉曼信号显着增强，这在其他金属离子显示出对该离子的选择性的情况下是看不到的。该研究有助于概念化，设计，