Effect of membrane properties on the odor emanating from training aids for explosive-detecting canines.

Canines are widely used for real-time detection of explosives and have proven to be on par with instrumental methods. Canines are thought to rely largely upon detection of volatile chemical constituents of the explosives, though not necessarily the explosive itself. Hence, it is crucial to understand the odor available to them as generated by training aids.

Screening of volatiles from explosive initiators and plastic-bonded explosives (PBX) using headspace solid-phase microextraction coupled with gas chromatography - mass spectrometry (SPME/GC-MS).

The detection of explosives and explosive devices based on the volatile compounds they emit is a long-standing tool for law enforcement and physical security. Toward that end, solid-phase microextraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS) has become a crucial analytical tool for the identification of volatiles emitted by explosives. Previous SPME studies have identified many volatile compounds emitted by common explosive formulations that serve as the main charge in explosive devices.

Superhydrophobic Surface Modification of Polymer Microneedles Enables Fabrication of Multimodal Surface-Enhanced Raman Spectroscopy and Mass Spectrometry Substrates for Synthetic Drug Detection in Blood Plasma.

Microneedles are widely used substrates for various chemical and biological sensing applications utilizing surface-enhanced Raman spectroscopy (SERS), which is indeed a highly sensitive and specific analytical approach. This article reports the fabrication of a nanoparticle (NP)-decorated microneedle substrate that is both a SERS substrate and a substrate-supported electrospray ionization (ssESI) mass spectrometry (MS) sample ionization platform. Polymeric ligand-functionalized gold nanorods (Au NRs) are adsorbed onto superhydrophobic surface-modified polydimethylsiloxane (PDMS) microneedles through the control of various interfacial interactions.

Characterization of an odor permeable membrane device for the storage of explosives and use as canine training aids.

The storage and use of explosives is regulated at the state and federal level, with a particular focus on physical security and rigorous accounting of the explosive inventory. For those working with explosives for the training and testing of explosive-detecting canines, cross-contamination is an important concern. Hence, explosives intended for use with canine teams must be placed into secondary storage containers that are new, clean, and airtight.

Studies into exfoliation and coating of Egyptian blue in methanol for application to the detection of latent fingermarks.

We have recently demonstrated that coated exfoliated Egyptian blue powder is effective for detecting latent fingermarks on a range of highly-patterned non-porous and semi-porous surfaces. In this extension of that work, we present our studies into an alternative approach to prepare exfoliated Egyptian blue coated with cetrimonium bromide and Tween® 20 using a simpler technique. The quality of the latent fingermarks developed with these exfoliated powders and the commercial powder were compared in acomprehensive study.

Quantitative analysis of smokeless powder particles in post-blast debris via gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV).

Forensic analysis of smokeless powder particles recovered from the debris of an improvised explosive device can provide information about the type of smokeless powder used and can aid investigation efforts. In this study, quantitative methods were used to yield information about the difference in the chemical composition of the particles pre- and post-blast. The technique, gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV), was able to quantify nitroglycerin, 2,4-dinitrotoluene, diphenylamine, ethyl centralite, and di-n-butyl phthalate in pre- and post-blast smokeless powder particles using heptadecane as an internal standard.

A systematic study of the absorbance of the nitro functional group in the vacuum UV region.

The nitro functional group (NO) features strongly in compounds such as explosives, pharmaceuticals, and fragrances. However, its gas phase absorbance characteristics in the vacuum UV region (120-200 nm) have not been systematically studied. Gas chromatography/vacuum UV spectroscopy (GC/VUV) was utilized to study the gas phase VUV spectra of various nitrated compounds (e.

Gas Chromatography-Mass Spectrometry Paired with Total Vaporization Solid-Phase Microextraction as a Forensic Tool.

Gas Chromatography - Mass Spectrometry (GC-MS) is a frequently used technique for the analysis of numerous analytes of forensic interest, including controlled substances, ignitable liquids, and explosives. GC-MS can be coupled with Solid-Phase Microextraction (SPME), in which a fiber with a sorptive coating is placed into the headspace above a sample or immersed in a liquid sample. Analytes are sorbed onto the fiber which is then placed inside the heated GC inlet for desorption.

Tracking the Progression of Triple Negative Mammary Tumors over Time by Chemometric Analysis of Urinary Volatile Organic Compounds.

Previous studies have shown that volatile organic compounds (VOCs) are potential biomarkers of breast cancer. An unanswered question is how urinary VOCs change over time as tumors progress. To explore this, BALB/c mice were injected with 4T1.

A critical comparison of vacuum UV (VUV) spectrometer and electron ionization single quadrupole mass spectrometer detectors for the analysis of alkylbenzenes in gasoline by gas chromatography: Experimental and statistical aspects.

Recent advances in benchtop vacuum ultraviolet (VUV) spectrometers have yielded effective universal detectors for gas chromatography (GC). The ability of these detectors to acquire absorbance spectra from 125 nm to 430 nm poses an alternative to the gold standard of mass spectrometry (MS) as a sensitive and selective GC detector. The applications of GC/VUV extend into many areas.

Enhancing Nonfouling and Sensitivity of Surface-Enhanced Raman Scattering Substrates for Potent Drug Analysis in Blood Plasma via Fabrication of a Flexible Plasmonic Patch.

Surface-enhanced Raman scattering (SERS) is an ultrasensitive analytical technique, which is capable of providing high specificity; thus, it can be used for toxicological drug assay (detection and quantification). However, SERS-based drug analysis directly in human biofluids requires mitigation of fouling and nonspecificity effects that commonly appeared from unwanted adsorption of endogenous biomolecules present in biofluids (e.g.

Detection of ɣ-hydroxybutyric acid (GHB) and ɣ-butyrolactone (GBL) in alcoholic beverages via total vaporization solid-phase microextraction (TV-SPME) and gas chromatography-mass spectrometry.

Total Vaporization Solid-Phase Microextraction (TV-SPME) relies on the same technique as standard SPME but completely vaporizes a sample extract, and analytes are sorbed directly from the vapor phase. On-fiber derivatization may also be performed using TV-SPME, where the fiber is first exposed to the headspace of a vial containing the derivatization agent, then exposed to a new vial containing the sample. ɣ-Hydroxybutyric acid (GHB) and ɣ-butyrolactone (GBL) are drugs of concern in that they may be used in drug facilitated sexual assault by surreptitiously spiking them into a victim's beverage.

Thermal and spectroscopic analysis of nitrated compounds and their break-down products using gas chromatography/vacuum UV spectroscopy (GC/VUV).

Gas chromatography/vacuum UV spectroscopy (GC/VUV) was utilized to study various explosives and pharmaceuticals in the nitrate ester and nitramine structural classes. In addition to generating specific VUV spectra for each compound, VUV was used to indicate the onset of thermal decomposition based upon the appearance of break-down products such as nitric oxide, carbon monoxide, formaldehyde, water, and molecular oxygen. The effect of temperature on decomposition could be fit to a logistical function where the fraction of intact compound remaining decreased as the transfer line/flow cell temperature was increased from 200 °C to 300 °C.

Optimization of the qualitative and quantitative analysis of cocaine and other drugs of abuse via gas chromatography - Vacuum ultraviolet spectrophotometry (GC - VUV).

Gas Chromatography-Vacuum UV Spectroscopy (GC-VUV) has seen increased attention in many areas, however, a statistical optimization of VUV method parameters has not been published. This article presents the first statistical optimization of parameters influencing analytes such as cocaine in the VUV flow-cell. Flow-cell temperature, make-up gas pressure, and carrier gas flow rate from the GC were examined and optimized for the detection of controlled substances.

Identifying Thermal Decomposition Products of Nitrate Ester Explosives Using Gas Chromatography-Vacuum Ultraviolet Spectroscopy: An Experimental and Computational Study.

Analysis of nitrate ester explosives (e.g., nitroglycerine) using gas chromatography-vacuum ultraviolet spectroscopy (GC-VUV) results in their thermal decomposition into nitric oxide, water, carbon monoxide, oxygen, and formaldehyde.

Instrumental and chemometric analysis of opiates via gas chromatography-vacuum ultraviolet spectrophotometry (GC-VUV).

Since its introduction, gas chromatography (GC) coupled to vacuum ultraviolet spectrophotometry (VUV) has been shown to complement mass spectrometry (MS) for materials such as petrochemicals, explosives, pesticides, and drugs. In forensic chemistry, opioids are commonly encountered but rarely are the samples pure. This work focuses on GC-VUV analysis applied to naturally occurring (e.

Preparation and characterization of micro-bore wall-coated open-tubular capillaries with low phase ratios for fast-gas chromatography-mass spectrometry: Application to ignitable liquids and fire debris.

Fast Gas Chromatography (GC) allows for analysis times that are a fraction of those seen in traditional capillary GC. Key modifications in fast GC include using narrow, highly efficient columns that can resolve mixtures using a shorter column length. Hence, a typical fast GC column has an inner diameter of 100-180 μm.

Generating highly specific spectra and identifying thermal decomposition products via Gas Chromatography / Vacuum Ultraviolet Spectroscopy (GC/VUV): Application to nitrate ester explosives.

Gas chromatography/mass spectrometry (GC/MS) is a "workhorse" instrument for chemical analysis, but it can be limited in its ability to differentiate structurally similar compounds. The coupling of GC to vacuum ultraviolet (VUV) spectroscopy is a recently developed technique with the potential for increased detection specificity. To date, GC/VUV has been demonstrated in the analysis of volatile organic compounds, petroleum products, aroma compounds, pharmaceuticals, illegal drugs, and lipids.

Fabrication of a self-assembled and flexible SERS nanosensor for explosive detection at parts-per-quadrillion levels from fingerprints.

Apart from high sensitivity and selectivity of surface-enhanced Raman scattering (SERS)-based trace explosive detection, efficient sampling of explosive residue from real world surfaces is very important for homeland security applications. Herein, we demonstrate an entirely new SERS nanosensor fabrication approach. The SERS nanosensor was prepared by self-assembling chemically synthesized gold triangular nanoprisms (Au TNPs), which we show display strong electromagnetic field enhancements at the sharp tips and edges, onto a pressure-sensitive flexible adhesive film.

Identification of 1-(2,3-dihydro-1H-inden-5-yl)-2-(ethylamino)pentan-1-one (bk-IVP) in a Seized Drug Exhibit.

To circumvent the law by evading regulation and obscuring their identities in routine analyses, numerous substituted cathinones have entered the illicit drug market. These compounds have been coined "bath salts" by users. In the described case, the laboratory received an unknown white powder for controlled substances identification.

Optimization of total vaporization solid-phase microextraction (TV-SPME) for the determination of lipid profiles of Phormia regina, a forensically important blow fly species.

A new method has been developed for the determination of fatty acids, sterols, and other lipids which naturally occur within pupae of the blow fly Phormia regina. The method relies upon liquid extraction in non-polar solvent, followed by derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) w/ 1% trimethylchlorsilane (TMCS) carried out inside the sample vial. The analysis is facilitated by total vaporization solid-phase microextraction (TV-SPME), with gas chromatography-mass spectrometry (GC-MS) serving as the instrumentation for analysis.

Mapping smokeless powder residue on PVC pipe bomb fragments using total vaporization solid phase microextraction.

Quantitating post-blast explosive residue is not a common practice in crime labs as it is typically not legally relevant. There is value in quantitation, however, if the distribution of residues on Improvised Explosive Devices (IEDs) can help guide future sample collection and/or method development. Total vaporization solid phase microextraction gas chromatography mass spectrometry (TV-SPME/GC/MS) was used to quantify residues of double-base smokeless powder (DBSP), which includes nitroglycerin (NG), diphenylamine (DPA), and ethyl centralite (EC) on post-blast PVC pipe bomb fragments.

A Comprehensive Study of the Alteration of Ignitable Liquids by Weathering and Microbial Degradation.

The differing effects of weathering and microbial degradation are described here in a comprehensive study that involved 50 different ignitable liquids from the Ignitable Liquids Database and Reference Collection. Examples of ignitable liquid residues from each of the main classes established by the American Society of Testing and Materials are presented. Weathering was accomplished via evaporation, whereas microbial degradation was carried out on soil at room temperature for periods of up to 21 days.

Factors Affecting Species Identifications of Blow Fly Pupae Based upon Chemical Profiles and Multivariate Statistics.

Alternative methods for the identification of species of blow fly pupae have been developed over the years that consist of the analyses of chemical profiles. However, the effect of biotic and abiotic factors that could influence the predictive manner for the tests have not been evaluated. The lipids of blowfly pupae (, , , and ) were extracted in pentane, derivatized, and analyzed by total-vaporization solid phase microextraction gas chromatography-mass spectrometry (TV-SPME GC-MS).