Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu 610031, China.
Department of Chemistry, University of Victoria, Victoria, BC V8W 3V6, Canada.
ACS Sens. 2020 Sep 25;5(9):2933-2939. doi: 10.1021/acssensors.0c01412. Epub 2020 Aug 31.
The advent of miniaturized, fiber-based, Raman spectrometers provides a clear path for the wide implementation of surface-enhanced Raman scattering (SERS) in analytical chemistry. For instance, miniaturized systems are especially useful in field applications due to their simplicity and low cost. However, traditional SERS substrates are generally developed and optimized using expensive Raman microscope systems equipped with high numerical aperture (NA) objective lenses. Here, we introduced a new type of SERS substrate with intrinsic Raman photon directing capability that compensates the relatively low signal collection power of fiber-based Raman spectrometers. The substrate was tested for the detection of buried 2,4-dinitrotoluene in simulated field conditions. A linear calibration curve ( = 0.98) for 2,4-dinitrotoluene spanning 3 orders of magnitude (from μg kg to mg kg) was obtained with a limit of detection of 10 μg kg within a total volume of 10 μL. This detection level is 2 orders of magnitude lower than that possible with the current state-of-the-art technologies, such as ion mobility spectrometry-mass spectrometry. The approach reported here demonstrated a high-performance detection of 2,4-dinitrotoluene in field conditions by a SERS platform optimized for miniaturized Raman systems that can be deployed for a routine inspection of landmine-contaminated sites and homeland security applications.
微型化、基于光纤的拉曼光谱仪的出现为表面增强拉曼散射（SERS）在分析化学中的广泛应用提供了明确的途径。例如，由于其简单性和低成本，微型系统在现场应用中特别有用。然而，传统的 SERS 衬底通常是使用配备高数值孔径（NA）物镜的昂贵拉曼显微镜系统来开发和优化的。在这里，我们引入了一种新型的 SERS 衬底，具有内在的拉曼光子导向能力，可以补偿基于光纤的拉曼光谱仪相对较低的信号收集能力。该衬底在模拟现场条件下对埋藏的 2,4-二硝基甲苯的检测进行了测试。在总共 10 μL 的体积内，2,4-二硝基甲苯的线性校准曲线（ = 0.98）跨越 3 个数量级（从μg kg 到 mg kg），检测限为 10 μg kg。这种检测水平比目前最先进的技术（如离子迁移谱-质谱）低 2 个数量级。这里报道的方法通过为微型化拉曼系统优化的 SERS 平台在现场条件下实现了 2,4-二硝基甲苯的高性能检测，该平台可用于对受地雷污染地区的例行检查和国土安全应用。
