Department of Chemistry, Materials Chemistry Centre, University College London, 20 Gordon St., London WC1H 0AJ, UK.
Department of Electronic and Electrical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
Nanoscale. 2017 Nov 2;9(42):16459-16466. doi: 10.1039/c7nr05057g.
Surface-enhanced Raman spectroscopy (SERS) has been widely utilised as a sensitive analytical technique for the detection of trace levels of organic molecules. The detection of organic compounds in the gas phase is particularly challenging due to the low concentration of adsorbed molecules on the surface of the SERS substrate. This is particularly the case for explosive materials, which typically have very low vapour pressures, limiting the use of SERS for their identification. In this work, silver nanocubes (AgNCs) were developed as a highly sensitive SERS substrate with very low limit-of-detection (LOD) for explosive materials down to the femtomolar (10 M) range. Unlike typical gold-based nanostructures, the AgNCs were found suitable for the detection of both aromatic and aliphatic explosives, enabling detection with high specificity at low concentration. SERS studies were first carried out using a model analyte, Rhodamine-6G (Rh-6G), as a probe molecule. The SERS enhancement factor was estimated as 8.71 × 10 in this case. Further studies involved femtomolar concentrations of 2,4-dinitrotoluene (DNT) and nanomolar concentrations of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), as well as vapour phase detection of DNT.
表面增强拉曼光谱（SERS）已被广泛应用于痕量有机分子检测的灵敏分析技术中。由于吸附在 SERS 基底表面上的分子浓度较低，因此在气相中检测有机化合物具有挑战性。对于爆炸材料来说尤其如此，因为它们的蒸汽压通常非常低，这限制了 SERS 对其进行识别的应用。在这项工作中，银纳米立方（AgNCs）被开发为一种高灵敏度的 SERS 基底，对爆炸材料的检测下限（LOD）低至飞摩尔（10 M）范围。与典型的基于金的纳米结构不同，AgNCs 被发现适合于检测芳香族和脂肪族爆炸物，能够在低浓度下进行高特异性检测。首先使用模型分析物罗丹明-6G（Rh-6G）进行 SERS 研究，作为探针分子。在这种情况下，SERS 增强因子估计为 8.71×10。进一步的研究涉及飞摩尔浓度的 2,4-二硝基甲苯（DNT）和纳摩尔浓度的 1,3,5-三硝基六氢-1,3,5-三嗪（RDX），以及 DNT 的气相检测。
