Sensitive and specific detection of explosives in solution and vapour by surface-enhanced Raman spectroscopy on silver nanocubes

Abstract

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.

Photo-induced enhanced Raman spectroscopy (PIERS): sensing atomic-defects, explosives and biomolecules

“…Raman spectroscopy is commonly used for molecular identification and characterization through the activation of specific molecular vibrational modes (allowing "fingerprint" molecular detection). [1][2][3][4] However, common applications of Raman spectroscopy were only developed in the last 50 years, primarily through the discovery of Surface Enhanced Raman Spectroscopy (SERS). Although originally hindered by the intrinsically low Raman cross-sections of most chemicals, the development of SERS substrates enabled significant spectral enhancements allowing detection of much lower analyte concentrations, resulting in what has now become a powerful analytical technique.…”

Diazotization-Coupling Reaction-Based Determination of Tyrosine in Urine Using Ag Nanocubes by Surface-Enhanced Raman Spectroscopy

“…The intensities of Raman peak at 1386 cm −1 for the SERS and normal Raman spectra were 51852 and 2139, the enhancement factor was 10 9 . The detailed calculation process can be found in previous work [ 17 , 31 , 32 ]. where I SERS is the SERS intensity of the analyte (in this case R6G).…”

“…The light field is located at the corner, which greatly enhances the strength of the electric field and generates the hot spot effect. AgNCs have been used to detect 2,4-dinitrotoluene (DNT) [ 17 ] and pesticides [ 18 ], and they have potential biosensing applications [ 19 ].…”

Durable Antimicrobial Behaviour from Silver-Graphene Coated Medical Textile Composites

“…However, the relative weakness of the bands for rGO samples indicates that the amount of impregnated/coated material is insufficient for a strong signal. However, silver-containing samples display a large signal enhancement, which is due to AgNP hot spots, i.e., it is a surface enhanced Raman spectroscopy (SERS) effect, and serves to mask most other signals [121][122][123]. The non-uniform enhancement of the respective Raman bands is a feature of SERS and makes it difficult to extract further I D /I G data.…”