Near-infrared surface-enhanced Raman scattering of trinitrotoluene on colloidal gold and silver

Kneipp, Katrin; Wei, Xiawei; Dasari, Ramachandra R.; Feld, Michael S.; Gilbert, B.; Janni, James A.; Steinfeld, J. I.

doi:10.1016/0584-8539(95)01474-7

Cited by 98 publications

(82 citation statements)

References 16 publications

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“…2 shows the Raman spectrum of 1 ng of TNT adsorbed on the SERS substrate. [3] The surface-enhanced symmetric stretching vibrations of the nitro group are slightly shifted respect to those of the 'normal' Raman spectrum, with a more pronounced smaller wavenumber component around 1330 cm −1 . The CH 3 symmetric bend shoulder is absent, suggesting a different interplay with the electron-donating methyl group in the TNT molecule when adsorbed on nano-structured substrates.…”

Section: Resultsmentioning

confidence: 99%

“…[12] In the SERS spectra, the vibrational modes of solvent are not observed and this finding can be accounted for considering that its vapour pressure is higher than that of NG. Moreover, since ethanol and methanol do not show any SERS effect, [3] even if the solvent was adsorbed on the substrate, its mass would be too small to be detected by Raman spectroscopy without surface enhancement.…”

Section: Resultsmentioning

confidence: 99%

“…The wavenumbers and relative intensities are in agreement with those in the Raman spectra of this molecule reported previously. [3,10,11,13,14] The TNT molecule can be identified by the symmetric and the asymmetric NO 2 stretching vibrations, observed at 1340, 1360 cm −1 and at 1535, 1620 cm −1 , respectively. The shoulder at 1380 cm −1 may be assigned to the CH 3 symmetric bend, and its presence indicates an interaction with the electrondonating methyl group which sets TNT apart from most of the explosives belonging to nitro aromatic group.…”

Section: Resultsmentioning

confidence: 99%

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Surface‐enhanced Raman spectroscopy for trace‐level detection of explosives

Botti

Cantarini

Palucci

2010

J Raman Spectroscopy

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The detection of explosives and their associated compounds for security screening is an active area of research and a wide variety of detection methods are involved in this very challenging area. Surface-enhanced Raman scattering (SERS) spectroscopy is one of the most sensitive tools for the detection of molecules adsorbed on nano-scale roughened metal surface. Moreover, SERS combines high sensitivity with the observation of vibrational spectra of species, giving complete information on the molecular structure of material under study. In this paper, SERS was applied to the detection of very small quantities of explosives adsorbed on industrially made substrates. The spectra were acquired with a compact Raman spectrometer. Usually, a high signal-to-noise (S/N) spectrum, suitable for identification of explosive molecules down to few hundreds of picograms, was achieved within 30 s. Our measurements suggest that it is possible to exploit SERS using a practical detection instrument for routine analysis.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Surface‐enhanced Raman spectroscopy for trace‐level detection of explosives

Botti

Cantarini

Palucci

2010

J Raman Spectroscopy

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“…[5][6][7][8] The fi rst nanostructures that were used as SERS substrates for analytical applications were random metal nanostructures that can be described by fractal models such as colloidal aggregates or electrochemically roughened surfaces. [ 9 , 10 ] While these substrates have been successfully applied in many important sensing applications, [11][12][13][14] random substrates lack both basic engineering design rules and reproducibility and therefore do not fulfi ll the requirements for all SERS sensing applications. Especially demanding applications such as SERS bacterial pathogen biosensing, in which the unique vibration spectra of bacterial cells and their cell coatings are used for rapid pathogen identifi cation, [ 11 , 12 , 15-18 ] require a high degree of uniformity and reproducibility.…”

Section: Introductionmentioning

confidence: 99%

Engineering Nanoparticle Cluster Arrays for Bacterial Biosensing: The Role of the Building Block in Multiscale SERS Substrates

Yang

Yan

Premasiri

et al. 2010

Adv Funct Materials

110

133

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Noble metal nanoparticle cluster arrays (NCAs) are a novel class of engineered substrates for surface enhanced Raman spectroscopy (SERS), in which the noble metal nanoparticles interact on multiple length scales to create a multiscale E‐field cascade enhancement. In this work the role of the building block for the NCA performance is quantified. Periodic NCAs with constant cluster diameter (D = 200 nm) but variable nanoparticle diameter (d) and intercluster separation (Λ) were assembled on glass and their optical response and SERS enhancement were systematically characterized as a function of D, Λ, and d. An increase of d from 40 to 80 nm and simultaneous decrease of Λ from 200 to 50 nm led to an improvement of the ensemble averaged SERS enhancement factor by a factor of up to ∼8. The coefficient of variation (cv) of the enhancement factors (G) is significantly lower for the d = 80 nm NCAs than for the d = 40 nm and d = 60 nm NCAs. Optimized (D = 200 nm, Λ = 50 nm, d = 80 nm) NCAs show the overall highest signal reproducibility of all investigated NCAs and random nanoparticle substrates and achieve effective single cell detection sensitivity.

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“…Kneipp et al (87) have reported NIR surface-enhanced Raman scattering (SERS) of TNT on colloidal gold and silver. Addition of TNT to colloidal silver produced a strong coagulation, with the resulting particles too big to produce a large signal enhancement.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Laser‐ and Optical‐Based Techniques for the Detection of ExplosivesUpdate based on the original article by David L. Monts, Jagdish P. Singh and Gary M. Boudreaux,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

Hummel

Dubroca

2013

Encyclopedia of Analytical Chemistry

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A wide variety of optical‐ and laser‐based techniques have been and are currently being investigated as means of identifying and characterizing explosive materials. These efforts are hampered by the very low volatility of explosive compounds at room temperature and their tendency to ignite at higher temperatures where their vapor pressures are beginning to reach a regime where the species can be readily detected. Traditional, condensed‐phase absorption spectroscopy (both infrared (IR) and ultraviolet/ visible (UV/VIS)) requires larger samples than are frequently available and, although useful as confirmatory techniques, do not provide signatures that enable unique identification of species. The choice of nontraditional techniques for analysis of explosive materials is dependent upon the amount of sample available, the sample matrix, and sample‐imposed constraints upon the measurement. Raman spectroscopy can identify and quantify condensed phase explosive materials, but the detection limit depends upon substrate, excitation wavelength, and illumination area: limits of detection (LODs) vary from 0.05 ng for 2,4,6‐trinitrotoluene (TNT) on glass to 10 µg for nitroglycerin (NG) on silica gel. The other detection techniques considered require volatilization of either the explosive compound itself or more often of characteristic decomposition products, such as NO, NO 2 , or N 2 O. Using IR irradiation, researchers have demonstrated that photoacoustic spectroscopy (PAS) has detection limits ranging from 0.55 ppb (parts per billion) for vapor‐phase NG with 9 mm excitation to 220 ppm (parts per million) for vaporphase 2,4‐dinitrotoluene (DNT) with 6‐µm excitation. IR laser differential absorption detection of dissociation products NO, NO 2 , and/or N 2 O can achieve detection limits of a few picograms. Laser‐induced fluorescence (LIF) detection of the photofragments (typically NO) of explosive compounds yields detection limits in the tens to hundreds of ppb (by weight) range. Low LODs can be achieved using ion detection techniques: resonance‐enhanced multiphoton ionization (REMPI) spectrometry is capable of LODs for detecting vapor‐phase explosives compounds in the hundredths to tens of ppb range; ion mobility spectrometry (IMS) has vapor‐phase detection limits for common explosive compounds of typically 200 pg, but for some species can be significantly lower: for example, 1 pg for TNT.

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Near-infrared surface-enhanced Raman scattering of trinitrotoluene on colloidal gold and silver

Cited by 98 publications

References 16 publications

Surface‐enhanced Raman spectroscopy for trace‐level detection of explosives

Surface‐enhanced Raman spectroscopy for trace‐level detection of explosives

Engineering Nanoparticle Cluster Arrays for Bacterial Biosensing: The Role of the Building Block in Multiscale SERS Substrates

Laser‐ and Optical‐Based Techniques for the Detection of ExplosivesUpdate based on the original article by David L. Monts, Jagdish P. Singh and Gary M. Boudreaux,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

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