Fu Hao, Bao Haoming, Zhang Hongwen, Zhao Qian, Zhou Le, Zhu Shuyi, Wei Yi, Li Yue, Cai Weiping
Key Lab of Materials Physics, Anhui Key Lab of Nanomaterials and Nanotechnology, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences, Hefei 230031, P. R. China.
University of Science and Technology of China, Hefei 230026, P. R. China.
ACS Omega. 2021 Jul 12;6(29):18928-18938. doi: 10.1021/acsomega.1c02179. eCollection 2021 Jul 27.
Practical application of surface-enhanced Raman spectroscopy (SERS) is greatly limited by the inaccurate quantitative analyses due to the measuring parameter's fluctuations induced by different operators, different Raman spectrometers, and different test sites and moments, especially during the field tests. Herein, we develop a strategy of quantitative SERS for field detection via designing structurally homogeneous and ordered Ag-coated Si nanocone arrays. Such an array is fabricated as SERS chips by depositing Ag on the template etching-induced Si nanocone array. Taking 4-aminothiophenol as the typical analyte, the influences of fluctuations in measuring parameters (such as defocusing depth and laser powers) on Raman signals are systematically studied, which significantly change SERS measurements. It has been shown that the silicon underneath the Ag coating in the chip can respond to the measuring parameters' fluctuations synchronously with and similar to the analyte adsorbed on the chip surface, and the normalization with Si Raman signals can well eliminate the big fluctuations (up to 1 or 2 orders of magnitude) in measurements, achieving highly reproducible measurements (mostly, <5% in signal fluctuations) and accurate quantitative SERS analyses. Finally, the simulated field tests demonstrate that the developed strategy enables quantitatively analyzing the highly scattered SERS measurements well with 1 order of magnitude in signal fluctuation, exhibiting good practicability. This study provides a new practical chip and reliable quantitative SERS for the field detection of real samples.
表面增强拉曼光谱（SERS）的实际应用受到极大限制，因为不同操作人员、不同拉曼光谱仪、不同测试地点和时间所引起的测量参数波动会导致定量分析不准确，尤其是在现场测试中。在此，我们通过设计结构均匀且有序的镀银硅纳米锥阵列，开发了一种用于现场检测的定量SERS策略。通过在模板蚀刻诱导的硅纳米锥阵列上沉积银，将这种阵列制作为SERS芯片。以4-氨基硫酚作为典型分析物，系统研究了测量参数（如离焦深度和激光功率）的波动对拉曼信号的影响，这些波动会显著改变SERS测量结果。结果表明，芯片中银涂层下方的硅能够与吸附在芯片表面的分析物同步且类似地响应测量参数的波动，并且用硅拉曼信号进行归一化可以很好地消除测量中高达1或2个数量级的大幅波动，实现高度可重复的测量（大多数情况下，信号波动<5%）以及准确的定量SERS分析。最后，模拟现场测试表明，所开发的策略能够很好地对信号波动为1个数量级的高度分散的SERS测量进行定量分析，具有良好的实用性。本研究为实际样品的现场检测提供了一种新型实用芯片和可靠的定量SERS方法。
