Standoff laser-induced thermal emission of explosives

Galán-Freyle, Nataly Y.; Pacheco‐Londoño, Leonardo C.; Figueroa-Navedo, Amanda M.; Hernández‐Rivera, Samuel P.

doi:10.1117/12.2016067

Cited by 6 publications

(16 citation statements)

References 16 publications

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“…This procedure was demonstrated by Galán et al . with the same methodology . Their experiments were carried out with LITE and are similar to the ones presented in detail for PETN, in which separation and improved chemometrics detection and discrimination have been demonstrated.…”

Section: Resultsmentioning

confidence: 95%

“…Using a laser source to induce thermal emission from target HEMs is therefore highly suitable for stimulating strong IREs remotely. Recent studies involving the use of CO 2 lasers for trace HEM detection have demonstrated an improvement in signal‐to‐noise ratios (S/N), as reported by Galán and collaborators . In one of their studies, the reported S/N for the detection of pentaerythritol tetranitrate (PETN) represented a significant improvement in this spectroscopic figure of merit for the spectroscopic region measured .…”

Section: Introductionmentioning

confidence: 80%

“…The data acquisition for the emission spectra in remote IR detection mode involved three steps (similar to the procedure used by Galan et al . ). Namely, the sample was first heated using the CO 2 laser at a specific power for a given time (induction heating).…”

Section: Methodsmentioning

confidence: 97%

“…The resulting setup was similar to the one used by Galán et al . . The Fourier transform infrared (FT‐IR) spectrometer used was a model EM27 OP/FT‐IR interferometer (Bruker Optics, Billerica, MA, USA).…”

Section: Methodsmentioning

confidence: 99%

“…The laser was then turned off, and the shutter was opened. Finally, thermal emissions were acquired by the telescope‐coupled FT‐IR in the time interval during which the sample was cooling .…”

Section: Methodsmentioning

confidence: 99%

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Chemometrics‐enhanced laser‐induced thermal emission detection of PETN and other explosives on various substrates

Figueroa-Navedo

Galán-Freyle

Pacheco‐Londoño

et al. 2015

Journal of Chemometrics

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Infrared emissions (IREs) of samples of pentaerythritol tetranitrate (PETN) deposited as contamination residues on various substrates were measured to generate models for the detection and discrimination of the important nitrate ester from the emissions of the substrates. Mid-infrared emissions were generated by heating the samples remotely using laser-induced thermal emission (LITE). Chemometrics multivariate analysis techniques such as principal component analysis (PCA), soft independent modeling by class analogy (SIMCA), partial least squares-discriminant analysis (PLS-DA), support vector machines (SVMs), and neural network (NN) were employed to generate the models for the classification and discrimination of PETN IREs from substrate thermal emissions. PCA exhibited less variability for the LITE spectra of PETN/substrates. SIMCA was able to predict only 44.7% of all samples, while SVM proved to be the most effective statistical analysis routine, with a discrimination performance of 95%. PLS-DA and NN achieved prediction accuracies of 94% and 88%, respectively. High sensitivity and specificity values were achieved for five of the seven substrates investigated.

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Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 80%

Section: Methodsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Chemometrics‐enhanced laser‐induced thermal emission detection of PETN and other explosives on various substrates

Figueroa-Navedo

Galán-Freyle

Pacheco‐Londoño

et al. 2015

Journal of Chemometrics

Self Cite

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Quantum cascade laser back‐reflection spectroscopy at grazing‐angle incidence using the fast Fourier transform as a data preprocessing algorithm

Pacheco‐Londoño

Galán-Freyle

et al. 2019

Journal of Chemometrics

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A simple optical layout for a grazing-angle probe (GAP) mount for coupling to a midinfrared (MIR) quantum cascade laser (QCL) spectrometer is described.This assembly enables reflectance measurements at high incident angles. In the case of optically thin films and deposits on MIR reflective substrates, a double-pass effect occurs, which is accompanied by the absorption of deposited samples in a reflection-absorption infrared spectroscopy modality. The optical system allows MIR light to pass through the sample twice.Applications to cleaning validation and detection of traces of explosives using the QCL-GAP is reported. Principal component analysis and partial least squares multivariate chemometrics methods were employed to analyze MIR spectra to evaluate an analytical methodology for confirming the presence of residues of pharmaceutically active ingredients (irbesartan) and of traces of explosives (cyclotrimethylenetrinitramine [RDX]) that have been deposited on metallic substrates. The performance of spectral preprocessing via fast Fourier transform (FFT) analysis was evaluated for the ability to extract more powerful and accurate information from the obtained reflectance spectra.According to the figures of merit of this new technique, FFT with chemometric routines can obtain sensitivity and specificity values of 1.000. The limits of detection that were obtained for irbesartan and RDX were 26 and 8 ng/cm 2 , respectively. The experimental results demonstrate that the proposed system, when used together with proper chemometrics routines, constitutes a powerful tool for the development of methodologies that have lower detection limits for a range of applications that involve detecting traces of analytes that reside on substrates as contaminants. KEYWORDS fast Fourier transform (FFT), grazing angle MIR laser spectroscopy, irbesartan/RDX, partial least squares (PLS), principal component analysis (PCA)

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Broad spectrum infrared thermal desorption of wipe-based explosive and narcotic samples for trace mass spectrometric detection

Forbes

Staymates

Sisco

2017

Analyst

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Wipe collected analytes were thermally desorbed using broad spectrum near infrared heating for mass spectrometric detection. Employing a twin tube filament-based infrared emitter, rapid and efficiently powered thermal desorption and detection of nanogram levels of explosives and narcotics was demonstrated. The infrared thermal desorption (IRTD) platform developed here used multi-mode heating (direct radiation and secondary conduction from substrate and subsequent convection from air) and a temperature ramp to efficiently desorb analytes with vapor pressures across eight orders of magnitude. The wipe substrate experienced heating rates up to (85 ± 2) °C s−1 with a time constant of (3.9 ± 0.2) s for 100% power emission. The detection of trace analytes was also demonstrated from complex mixtures, including plastic-bonded explosives and exogenous narcotics, explosives, and metabolites from collected artificial latent fingerprints. Manipulation of the emission power and duration directly controlled the heating rate and maximum temperature, enabling differential thermal desorption and a level of upstream separation for enhanced specificity. Transitioning from 100% power and 5 s emission duration to 25% power and 30 s emission enabled an order of magnitude increase in the temporal separation (single seconds to tens of seconds) of the desorption of volatile and semi-volatile species within a collected fingerprint. This mode of operation reduced local gas-phase concentrations, reducing matrix effects experienced with high concentration mixtures. IRTD provides a unique platform for the desorption of trace analytes from wipe collections, an area of importance to the security sector, transportation agencies, and customs and border protection.

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Standoff laser-induced thermal emission of explosives

Cited by 6 publications

References 16 publications

Chemometrics‐enhanced laser‐induced thermal emission detection of PETN and other explosives on various substrates

Chemometrics‐enhanced laser‐induced thermal emission detection of PETN and other explosives on various substrates

Quantum cascade laser back‐reflection spectroscopy at grazing‐angle incidence using the fast Fourier transform as a data preprocessing algorithm

Broad spectrum infrared thermal desorption of wipe-based explosive and narcotic samples for trace mass spectrometric detection

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