The effect of the pH on the interaction of L-arginine with colloidal silver nanoparticles. A Raman and SERS study
The effect of the pH on the interaction of L-arginine with colloidal silver nanoparticles. A Raman and SERS study
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DOI：
10.1002/jrs.4331
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发表时间：
2013-08-01
影响因子：
2.5
通讯作者：
Campos-Vallette, M. M.
中科院分区：
文献类型：
--
作者：
Garrido, C.;Aguayo, T.;Campos-Vallette, M. M.
利用拉曼光谱和表面增强拉曼散射（SERS）光谱研究了pH值（7 ~ 9）对精氨酸（Arg）与胶体银纳米粒子（AgNps）相互作用的影响。为了在溶液中获得可重复的SERS光谱，实现了一种新的方法。讨论了精氨酸浓度对AgNps稳定性的影响。当胶体溶液的pH值增加到Arg- pKa(2)值的极限时，可诱导出优先且稳定的Arg-金属相互作用。研究了不同pH条件下Arg-AgNps体系的电位测量，提供了Arg-AgNps相互作用的信息；pH值的增加有利于相互作用。在pH值为7时，SERS光谱表明该分子仅通过胍片与Ag表面相互作用。当pH值增加到9时，分子在表面呈现新的构象；金属与分析物的相互作用通过胍、羧酸盐和脂肪族部分得到验证。此外，使用扩展的Huckel方法对Ag与Ag表面相互作用的模型进行的理论计算支持观察到的SERS结果。版权所有：John Wiley & Sons， Ltd。
Raman and surface enhanced Raman scattering (SERS) spectroscopies were used to study the pH effect (7 to 9) on the interaction of arginine (Arg) with colloidal Ag nanoparticles (AgNps). A new methodology was implemented in order to obtain reproducible SERS spectra in solution. The dependence of the Arg concentration on the stability of the AgNps is discussed. A pH increasing of the colloidal solution to the limits of the Arg pKa(2) value induces a preferential and stable Arg-metal interaction. potential measurements of the Arg-AgNps system at different pH conditions studied provide information about the Arg-AgNps interaction; the pH increasing favors the interaction. SERS spectra at pH 7 indicate that the molecule interacts with the Ag surface only through the guanidinium fragment. By increasing the pH to 9, the molecule adopts a new conformation on the surface; the metal-analyte interaction is verified through the guanidinium, carboxylate and the aliphatic moieties. In addition, theoretical calculations performed by using the extended Huckel method for a model of Arg interacting with an Ag surface support the observed SERS results. Copyright (c) 2013 John Wiley & Sons, Ltd.