A positively charged silver nanowire membrane for rapid on-site swabbing extraction and detection of trace inorganic explosives using a portable Raman spectrometer

Abstract

The sensitive and on-site detection of inorganic explosives has raised serious concerns regarding public safety. However, high stability and non-volatility features currently limit their rapid on-site detection. Surface-enhanced Raman spectroscopy (SERS) is emerging as a powerful technique for the trace-level detection of different molecules. Plasmonic Ag nanowires were produced by a hydrothermal synthesis method using polyvinylpyrrolidone (PVP) as a negatively charged stabilizer. Here, we report a rapid detection method for inorganic explosives based on a simple surface swab with a positively charged diethyldithiocarbamate-modified Ag nanowire membrane coupled with SERS. This membrane, serving as an excellent SERS substrate with high uniformity, stability, and reusability, can capture both typical oxidizers in inorganic explosives and organic nitro-explosives, via electrostatic interaction. The detection level of perchlorates (ClO 4 − ), chlorates (ClO 3 − ), nitrates (NO 3 − ), picric acid, and 2,4-dinitrophenol is as high as 2.0, 1.7, 0.1, 45.8, and 36.6 ng, respectively. In addition, simulated typical inorganic explosives such as black powders, firecrackers, and match heads could also be detected. We believe that this membrane represents an attractive alternative for rapid on-site detection of inorganic explosives with high efficiency.

Synthesis of “walnut‐like” BiOCl/Br solid solution photocatalyst by electrostatic self‐assembly method

“…As can be seen from Figure , the BiOX compound crystallized in the tetragonal PbFCl‐type, and the space group was D 4 h 7 . BiOX has A 1g , B 1g , and E g representing three central symmetric vibration modes, all of which are composed of two distinct bands and two weak bands . Due to the symmetry vibration often results in more intense Raman band than the asymmetry vibration, therefore, for the pure BiOCl, at 59.96 cm −1 , 143.23 cm −1 belt, respectively, attributed to Bi‐Cl of A 1g stretching and A 1g stretching mode, 199.20 cm −1 weak band Raman peaks due to Bi‐Cl E g vibration mode, 386.95 cm −1 weak belt to E g by oxygen and B 1g belt movement vibration patterns of ploidy.…”

“…BiOX has A 1g , B 1g , and E g representing three central symmetric vibration modes, all of which are composed of two distinct bands and two weak F I G U R E 1 X-ray diffraction (XRD) patterns of BiOCl photocatalysts F I G U R E 2 Raman spectra of BiOCl photocatalysts bands. 10,15,[43][44][45] Due to the symmetry vibration often results in more intense Raman band than the asymmetry vibration, therefore, for the pure BiOCl, at 59.96 cm −1 , 143.23 cm −1 belt, respectively, attributed to Bi-Cl of A 1g stretching and A 1g stretching mode, 46 199.20 cm −1 weak band Raman peaks due to Bi-Cl E g vibration mode, 386.95 cm −1 weak belt to E g by oxygen and B 1g belt movement vibration patterns of ploidy. With the increase of X, the Bi-X Raman peak shifts to the low frequency direction, which may be that Br − enters the lattice of BiOCl, causing lattice vibration, 47 thus indicating the formation of solid solution.…”

Natural Deposition Strategy for Interfacial, Self‐Assembled, Large‐Scale, Densely Packed, Monolayer Film with Ligand‐Exchanged Gold Nanorods for In Situ Surface‐Enhanced Raman Scattering Drug Detection

“…Eur.J. SERS as a reliable molecular vibrational detection methodh olds great promise foru se on complex biological systems due to high sensitivity and selectivity.O wing to miniaturization, portability, and large spot area, ap ortable Raman spectrometer has been widely applied to drug abuse, [24] pollutants, [25] explosives, [26] and food safety. These resultsd emonstrate the feasibility of the automatic self-assembly deposition method, natural deposition, with good reliability and reproducibility.T oc omparet he performance of the substrate, untreated Au NRs obtained by centrifugation and drying werea lso measured to obtain the refer-ence information.…”

DART-MS analysis of inorganic explosives using high temperature thermal desorption

“…Traditional analytical techniques for the detection of explosive compounds have been geared toward the detection of the organic components and require significant adjustments from typical operating procedures for the analysis of inorganics. 1–3 The trace detection of the inorganic oxidizer component of fuel-oxidizer mixtures has progressed in recent years and includes colorimetric, 4 capillary electrophoresis (CE), 5,6 Raman spectroscopy, 7,8 ion chromatography (IC), 9 acidic reagent chemical conversion for thermal desorption (TD) ion mobility spectrometry (IMS) 10 and mass spectrometry (MS), 11–13 electrospray ionization (ESI) MS, 14,15 and ambient mass spectrometry. 16–21 …”