Utilizing Molecular Hyperpolarizability for Trace Analysis: A Surface-Enhanced Hyper-Raman Scattering Study of Uranyl Ion
Utilizing Molecular Hyperpolarizability for Trace Analysis: A Surface-Enhanced Hyper-Raman Scattering Study of Uranyl Ion
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DOI：
10.1021/acsomega.8b01147
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发表时间：
2018-06
期刊：
影响因子：
4.1
通讯作者：
M. J. Trujillo;J. Camden
中科院分区：
文献类型：
--
作者：
M. J. Trujillo;J. Camden
表面增强超拉曼散射（SEHRS）是表面增强拉曼散射（Sers）的非线性模拟，它提供了由分子超极化引起的独特光谱特征。在这项工作中，我们探讨了表面结合的铀酰离子的Sers和SEHRS光谱之间的差异。利用独特的SEHRS波段痕量检测的铀酰离子，我们获得了优异的灵敏度（检测限= 90 ppb），尽管超拉曼效应的极端弱点。我们观察到，结合铀酰离子的羧酸基团的4-巯基苯甲酸（4-MBA）导致显着的变化，在SEHRS光谱，而表面增强拉曼散射（Sers）光谱相同的复杂的变化不大。Sers和SEHRS光谱也被检查作为两个取代基位置的函数，使用2-MBA，3-MBA，和4-MBA，和碳链长度，使用4-巯基苯乙酸和4-巯基苯丙酸。这些结果表明，SEHRS的独特功能，可以产生更多的信息比Sers在某些情况下，代表SEHRS的非共振分子的痕量分析的第一个应用。
Surface-enhanced hyper-Raman scattering (SEHRS), the nonlinear analog of surface-enhanced Raman scattering (SERS), provides unique spectral signatures arising from the molecular hyperpolarizability. In this work, we explore the differences between SERS and SEHRS spectra obtained from surface-bound uranyl ion. Exploiting the distinctive SEHRS bands for trace detection of the uranyl ion, we obtain excellent sensitivity (limit of detection = 90 ppb) despite the extreme weakness of the hyper-Raman effect. We observe that binding the uranyl ion to the carboxylate group of 4-mercaptobenzoic acid (4-MBA) leads to significant changes in the SEHRS spectrum, whereas the surface-enhanced Raman scattering (SERS) spectrum of the same complex is little changed. The SERS and SEHRS spectra are also examined as a function of both substituent position, using 2-MBA, 3-MBA, and 4-MBA, and the carbon chain length, using 4-mercaptophenylacetic acid and 4-mercaptophenylpropionic acid. These results illustrate that the unique features of SEHRS can yield more information than SERS in certain cases and represent the first application of SEHRS for trace analysis of nonresonant molecules.