Laboratory-scale techniques for the measurement of a material response to an explosive blast

Laboratory-scale experiments were performed to measure the deformation of thin plates in response to varying explosive impulse. Experiments were conducted with a known explosive mass suspended in air at a known distance from an aluminum witness plate clamped in a “shock-hole” fixture. Through the use of well-characterized PETN and TATP explosive charges, the explosive impulse applied to each witness plate was determined a priori. The witness-plate response was measured using high-speed digital cameras to determine time-resolved, three-dimensional surface motion and maximum plate deformation. The results show that the maximum dynamic plate deformation is a straightforward function of applied explosive impulse, as determined from the explosive characterization. The experimental trend is the same despite the two different explosives used, highlighting that explosive impulse, determined through a blast characterization, is the controlling parameter in material blast response. A new experimental technique is used here to measure the dynamic blast response and the experimental errors are documented. Ultimately, applications of laboratory-scale explosive testing to computational code validation, material response scaling, and high-speed material property definition are discussed.     

Trace detection and discrimination of explosives using electrochemical potentiometric gas sensors

In this article, selective and sensitive detection of trace amounts of pentaerythritol tetranitrate (PETN), 2,4,6-trinitrotoluene (TNT) and cyclotrimethylenetrinitramine (RDX) is demonstrated. The screening system is based on a sampling/concentrator front end and electrochemical potentiometric gas sensors as the detector. Preferential hydrocarbon and nitrogen oxide(s) mixed potential sensors based on lanthanum strontium chromite and Pt electrodes with yttria stabilized zirconia (YSZ) solid electrolyte were used to capture the signature of the explosives. Quantitative measurements based on hydrocarbon and nitrogen oxide sensor responses indicated that the detector sensitivity scaled proportionally with the mass of the explosives (1-3 μg). Moreover, the results showed that PETN, TNT, and RDX samples could be discriminated from each other by calculating the ratio of nitrogen oxides to hydrocarbon integrated area under the peak. Further, the use of front-end technology to collect and concentrate the high explosive (HE) vapors make intrinsically low vapor pressure of the HE less of an obstacle for detection while ensuring higher sensitivity levels. In addition, the ability to use multiple sensors each tuned to basic chemical structures (e.g., nitro, amino, peroxide, and hydrocarbon groups) in HE materials will permit the construction of low-cost detector systems for screening a wide spectrum of explosives with lower false positives than present-day technologies.     

Identification of high explosives using single-particle aerosol mass spectrometry

The application of single-particle aerosol mass spectrometry (SPAMS) to the real-time detection of micrometer-sized single particles of high explosives is described. Dual-polarity time-of-flight mass spectra from 1000 single particles each of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and pentaerythritol tetranitrate (PETN), as well as those of complex explosives, Composition B, Semtex 1A, and Semtex 1H, were obtained over a range of desorption/ionization laser fluences between 0.50 and 8.01 nJ/microm2. Mass spectral variability with laser fluence for each explosive is discussed. The ability of the SPAMS system to identify explosive components in a single complex explosive particle ( approximately 1 pg) without the need for consumables is demonstrated.     

Determination of peroxide-based explosives using liquid chromatography with on-line infrared detection

A nondestructive analytical method for peroxide-based explosives determination in solid samples is described. Reversed-phase high-performance liquid chromatography in combination with on-line Fourier transform infrared (FT-IR) detection is used for the analysis of triacetonetriperoxide (TATP) and hexamethylenetriperoxide diamine (HMTD). In contrast to other liquid chromatographic methods with optical detection, no derivatization or decomposition of the peroxides is required. The peroxides are identified and quantified via their characteristic absorption spectra in the mid-infrared range of the electromagnetic spectrum. The detection limit of 0.5 mmol L-1 for HMTD and 1 mmol L-1 for TATP allows the identification of the explosives in complex matrixes.     

Fast separation and quantification method for nitroguanidine and 2,4-dinitroanisole by ultrafast liquid chromatography-tandem mass spectrometry

Explosives are now persistent environmental pollutants that are targets of remediation and monitoring in a wide array of environmental media. Nitroguanidine (NG) and 2,4-dinitroanisole (DNAN) are two insensitive energetic compounds recently used as munitions explosives. To protect our environment and human health, the levels of these compounds in soils and waters need to be monitored. However, no sensitive analytical methods, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS), have been developed for detecting these new compounds at trace levels and to be concurrently applied to monitor the common explosives. In general, the concentrations of explosives in either soil or water samples are very low and widely distributed. Therefore, a fast and sensitive method is required to monitor those compounds and increase our ability to find and address the threats they pose to human health and ecological receptors. In this study, a fast and sensitive analytical method has been developed to quantitatively determine NG and DNAN in soil, tap water, and river water by using ultrafast LC-MS/MS. To make this method a comprehensive analytical technique for other explosives as well, it has included other commonly used explosives in the method development, such as octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 1,3,5-trinitroper-hydro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), 2-amino-4,6-dinitrotoluene (ADNT), and pentaerythritol tetranitrate (PETN). The method detection limits (MDLs) of these compounds in soil ranged from 0.2 to 5 ppb, and a good linearity was obtained over a concentration range of 0.5-200 ppb. The recoveries of some compounds are equal to or better than the current EPA methods but with much higher sensitivities.     

Trace analysis of peroxide-based explosives

The first method for quantitative trace analysis of peroxide-based explosives is described. A reversed-phase high-performance liquid chromatography method with post-column UV irradiation and fluorescence detection for the analysis of triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) has been developed. After separation, the analytes are degraded photochemically to hydrogen peroxide, which is subsequently determined on the basis of the peroxidase-catalyzed oxidation of p-hydroxyphenylacetic acid to the fluorescent dimer. This two-step reaction scheme in combination with the respective blanks (photochemical reactor switched off) provides for high selectivity. The limits of detection were 2 x 10(-6) mol/L for both TATP and HMTD, respectively. The method has been applied to the analysis of real samples.     

In situ trace detection of peroxide explosives by desorption electrospray ionization and desorption atmospheric pressure chemical ionization

Desorption electrospray ionization (DESI) mass spectrometry is used for the rapid (<5 s), selective, and sensitive detection of trace amounts of the peroxide-based explosives, hexamethylene triperoxide diamine (HMTD), tetracetone tetraperoxide (TrATrP), and triacetone triperoxide (TATP), directly from ambient surfaces without any sample preparation. The analytes are observed as the alkali metal ion complexes. Remarkably, collision-induced dissociation (CID) of the HMTD, TATP, and TrATrP complexes with Na(+), K(+), and Li(+) occurs with retention of the metal, a process triggered by an unusual homolytic cleavage of the peroxide bond, forming a distonic ion. This is followed by elimination of a fragment of 30 mass units, shown to be the expected neutral molecule, formaldehyde, in the case of HMTD, but shown by isotopic labeling experiments to be ethane in the cases of TATP and TrATrP. Density functional theory (DFT) calculations support the suggested fragmentation mechanisms for the complexes. Binding energies of Na+ of 40.2 and 33.1 kcal/mol were calculated for TATP-Na(+) and HMTD-Na(+) complexes, suggesting a strong interaction between the peroxide groups and the sodium ion. Increased selectivity is obtained either by MS/MS or by doping the spray solvent with additives that produce the lithium and potassium complexes of TATP, HMTD, and TrATrP. Addition of dopants into the solvent spray increased the signal intensity by an order of magnitude. When pure alcohol or aqueous hydrogen peroxide was used as the spray solvent, the (HMTD + Na)+ complex was able to bind a molecule of alcohol (methanol or ethanol) or hydrogen peroxide, providing additional characteristic ions to increase the selectivity of analysis. DESI also allowed the rapid detection of peroxide explosives in complex matrixes such as diesel fuel and lubricants using single or multiple cation additives (Na(+), K(+), and Li(+), and NH4(+)) in the spray solvent. Low-nanogram detection limits were achieved for HMTD, TrATrP, and TATP in these complex matrixes. The DESI response was linear over 3 orders of magnitude for HMTD and TATP on paper surfaces (1-5000 ng), and quantification of both peroxide explosives from paper gave precisions (RSD) of less than 3%. The use of pure water and compressed air as the DESI spray solution and nebulizing gas, respectively, showed similar ionization efficiencies to those obtained using methanol/water mixtures and nitrogen gas (the typical choices). An alternative ambient method, desorption atmospheric pressure chemical ionization (DAPCI), was also used to detect trace amounts of HMTD and TATP in air by complexation with gas-phase ammonium ions (NH4(+)) generated by atmospheric pressure ammonia ionization.     

High-sensitivity detection of triacetone triperoxide (TATP) and its precursor acetone

Triacetone triperoxide (C(9)H(18)O(6), molecular mass of 222.24 g/mol) (TATP) is a powerful explosive that is easy to synthesize using commonly available household chemicals, acetone, and hydrogen peroxide 1 2. Because of the simplicity of its synthesis, TATP is often the explosive of choice for terrorists, including suicide bombers. For providing safety to the population, early detection of TATP and isolation of such individuals are essential. We report unambiguous, high-sensitivity detection of TATP and its precursor, acetone, using room-temperature quantum cascade laser photoacoustic spectroscopy (QCL-PAS). The available sensitivity is such that TATP, carried on a person (at a nominal body temperature of 37 degrees C), should be detectable at some distance. The combination of demonstrated detection of TATP and acetone should be ideal for screening at airports and other public places for providing increased public safety.     

Increasing selectivity for TNT-based explosive detection by synchronous luminescence and derivative spectroscopy with quantum yields of selected aromatic amines

The detection of explosive material is at the forefront of current analytical problems. A detection method is desired that is not restricted to detecting only explosive materials, but is also capable of identifying the origin and type of explosive. It is essential that a detection method have the selectivity to distinguish among compounds in a mixture of explosives. The nitro compounds found in explosives have low fluorescent yields or are considered to be non-fluorescent; however, after reduction, the amino compounds exhibit relatively high fluorescence. We discuss how to increase selectivity of explosive detection using fluorescence; this includes synchronous luminescence and derivative spectroscopy with appropriate smoothing. By implementing synchronous luminescence and derivative spectroscopy, we were able to resolve the reduction products of one major TNT-based explosive compound, 2,4-diaminotoluene, and the reduction products of other minor TNT-based explosives in a mixture. We also report for the first time the quantum yields of these important compounds. Relative quantum yields are useful in establishing relative fluorescence intensities and are an important spectroscopic measurement of molecules. Our approach allows for rapid, sensitive, and selective detection with the discrimination necessary to distinguish among various explosives.     

Determination of inorganic improvised explosive device signatures using laser electrospray mass spectrometry detection with offline classification

The mass spectral detection of low vapor pressure, inorganic-based explosive signatures including ammonium nitrate, chlorate, perchlorate, sugar, and the constituents contained within black powder are reported using laser electrospray mass spectrometry. The ambient pressure mass spectrometry technique combining nonresonant, femtosecond laser vaporization with electrospray postionization revealed primary and secondary signatures for trace quantities of inorganic explosives. A mixture of complexation agents in the electrospray solvent enabled the simultaneous detection of vaporized cations, anions, and neutrals in a single measurement. An offline classifier discriminated the inorganic-based explosives based on the mass spectral signatures resulting in high fidelity identification.     

Semi-automated detection of trace explosives in fingerprints on strongly interfering surfaces with Raman chemical imaging

We have previously demonstrated the use of wide-field Raman chemical imaging (RCI) to detect and identify the presence of trace explosives in contaminated fingerprints. In this current work we demonstrate the detection of trace explosives in contaminated fingerprints on strongly Raman scattering surfaces such as plastics and painted metals using an automated background subtraction routine. We demonstrate the use of partial least squares subtraction to minimize the interfering surface spectral signatures, allowing the detection and identification of explosive materials in the corrected Raman images. The resulting analyses are then visually superimposed on the corresponding bright field images to physically locate traces of explosives. Additionally, we attempt to address the question of whether a complete RCI of a fingerprint is required for trace explosive detection or whether a simple non-imaging Raman spectrum is sufficient. This investigation further demonstrates the ability to nondestructively identify explosives on fingerprints present on commonly found surfaces such that the fingerprint remains intact for further biometric analysis.     

Some properties of explosive mixtures containing peroxides Part I. Relative performance and detonation of mixtures with triacetone triperoxide

This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. The detonation energies, E0, and detonation velocities, D, were calculated for the mixtures studied by means of the thermodynamic code CHEETAH. Relationships have been found and are discussed between the RP and the E0 values related to unit volume of gaseous products of detonation of these mixtures. These relationships together with those between RP and oxygen balance values of the mixtures studied indicate different types of participation of AN and UN in the explosive decomposition of the respective mixtures. Dry TATP/UN mixtures exhibit lower RP than analogous mixtures TATP/AN containing up to 25% of water. Depending on the water content, the TATP/AN mixtures possess higher detonability values than the ANFO explosives. A semi-logarithmic relationship between the D values and oxygen coefficients has been derived for all the mixtures studied at the charge density of 1000 kg m(-3). Among the mixtures studied, this relationship distinguishes several samples of the type of "tertiary explosives" as well as samples that approach "high explosives" in their performances and detonation velocities.     

Molecularly imprinted Au nanoparticles composites on Au surfaces for the surface plasmon resonance detection of pentaerythritol tetranitrate, nitroglycerin, and ethylene glycol dinitrate

Molecularly imprinted Au nanoparticles (NPs) composites are generated on Au-coated glass surfaces. The imprinting process involves the electropolymerization of thioaniline-functionalized Au NPs (3.5 nm) on a thioaniline monolayer-modified Au surface in the presence of a carboxylic acid, acting as a template analogue for the respective explosive. The exclusion of the imprinting template from the Au NPs matrix yields the respective imprinted composites. The binding of the analyte explosives to the Au NPs matrixes is probed by surface plasmon resonance spectroscopy, SPR, where the electronic coupling between the localized plasmon of the Au NPs and the surface plasmon wave leads to the amplification of the SPR responses originating from the dielectric changes of the matrixes upon binding of the different explosive materials. The resulting imprinted matrixes reveal high affinities and selectivity toward the imprinted explosives. Using citric acid as an imprinting template, Au NPs matrixes for the specific analysis of pentaerythritol tetranitrate (PETN) or of nitroglycerin (NG) were prepared, leading to detection limits of 200 fM and 20 pM, respectively. Similarly, using maleic acid or fumaric acid as imprinting templates, high-affinity sensing composites for ethylene glycol dinitrate (EGDN) were synthesized, leading to a detection limit of 400 fM for both matrixes.     

火炸药产品用包装物现状及发展趋势

目的总结我国火炸药产品用包装物的现状及发展趋势。方法梳理火炸药产品包装物应具有的基本功能,分析国内火炸药产品包装物及其标准现状,指出现有包装物及其标准存在的问题,总结未来火炸药产品用包装物的发展趋势。结果我国火炸药包装物采用的苏式箱包装、木箱包装和纸桶包装等3种形式,虽然能够满足火炸药产品贮存、运输的要求,但其在结构、材质、加工工艺及使用等方面落后的现状,逐渐暴露出不少问题;火炸药包装物标准使用年限长,至今未换版,在使用过程中也存在一定的争议。结论优化包装物的材料和结构,适应火炸药和弹药的自动化、智能化制造需要是未来火炸药产品包装物发展的重要趋势。     

Desorption electrospray ionization of explosives on surfaces: sensitivity and selectivity enhancement by reactive desorption electrospray ionization

Desorption electrospray ionization (DESI), an ambient mass spectrometry technique, is used for trace detection of the explosives trinitrohexahydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 2,4,6-trinitrotoluene (TNT), Pentaerythritol tetranitrate (PETN), and their plastic compositions (Composition C-4, Semtex-H, Detasheet) directly from a wide variety of surfaces (metal, plastic, paper, polymer) without sample preparation or pretreatment. Analysis of the explosives is performed under ambient conditions from virtually any surface in very short times (<5 s) including confirmatory tandem mass spectrometry (MS/MS) experiments, while retaining the sensitivity and specificity that mass spectrometry offers. Increased selectivity is obtained both by MS/MS and by performing additional experiments in which additives are included in the spray solvent. These reactive DESI experiments (reactions accompanying desorption) produce such ions as the chloride and trifluoroacetate adducts of RDX and HMX or the Meisenheimer complex of TNT. Desorption atmospheric pressure chemical ionization, a variant of DESI that uses gas-phase ions generated by atmospheric pressure corona discharges of toluene or other organic compounds, provides evidence for a heterogeneous-phase (gaseous ion/absorbed analyte) charge-transfer mechanism of DESI ionization in the case of explosives. Plastic explosives on surfaces were analyzed directly as fingerprints, without sample preparation, to test DESI as a possible method for in situ detection of explosives-contaminated surfaces. DESI also allowed detection of explosives in complex matrixes, including lubricants, household cleaners, vinegar, and diesel fuel. Absolute limits of detection for the neat explosives were subnanogram in all cases and subpicogram in the case of TNT. The DESI response was linear over 3 orders of magnitude for TNT. Quantification of RDX on paper gave a precision (RSD) of 2.3%. Pure water could be used as the spray solution for DESI, and it showed ionization efficiencies for RDX in the negative ion mode similar to that given by methanol/water. DESI represents a simple and rapid way to detect explosives in situ with high sensitivity and specificity and is especially useful when they are present in complex mixtures or in trace amounts on ordinary environmental surfaces.     

Sensors--an effective approach for the detection of explosives

The detection of explosives and explosive related illicit materials is an important area for preventing terrorist activities and for putting a check on their deleterious effects on health. A number of different methods, based on different principles, have been developed in the past for the detection of explosives. Sensors are one of those methods of detection which have capability to mimic the canine system and which are known to be the most reliable method of detection. The objective of this review is to provide comprehensive knowledge and information on the sensors operating on different transduction principles, ranging from electrochemical to immunosensors, being used for the detection of explosives as they pose a threat for both health and security of the nation. The review focuses mainly on the sensors developed in the recent 5 years and is prepared through summary of literature available on the subject.     

俄罗斯爆破器材的发展历程与现状

综述了俄罗斯爆破器材的发展历程与现状。概述了俄罗斯工业炸药从达纳迈特炸药到代表当今世界发展趋势的ANFO炸药和乳化炸药的转变和发展过程 ,并介绍了俄罗斯常用工业炸药的品种、性能。同时 ,还介绍了俄罗斯起爆器材及起爆系统的发展概况。最后 ,提出了世界各国爆破器材今后的发展方向。     

俄罗斯爆破器材的发展历程与现状

综述了俄罗斯爆破器材的发展历程与现状。概述了俄罗斯工业炸药从达纳迈特炸药到代表当今世界发展趋势的ANFO炸药和乳化炸药的转变和发展过程 ,并介绍了俄罗斯常用工业炸药的品种、性能。同时 ,还介绍了俄罗斯起爆器材及起爆系统的发展概况。最后 ,提出了世界各国爆破器材今后的发展方向。     

Application of selected-ion flow tube mass spectrometry to the real-time detection of triacetone triperoxide

A fast, efficient, real-time method for the quantitative analysis of the peroxide explosive, TATP, is described. The method utilizes rapid ion-molecule reactions of chemical reagent ions with the vapor above solid TATP. The reactions of three reagent ions (H3O+, O2+, NO+) were examined. Although all three ions exhibited a near-collision-rate reaction with TATP, only NO+ showed product ions that provide unequivocal evidence for a TATP-based explosive. The limit of detection of TATP in the gas phase is 10 ppb (4 x 10(-10) mol L(-1)).     

In-injection port thermal desorption for explosives trace evidence analysis

A gas chromatographic method utilizing thermal desorption of a dry surface wipe for the analysis of explosives trace chemical evidence has been developed and validated using electron capture and negative ion chemical ionization mass spectrometric detection. Thermal desorption was performed within a split/splitless injection port with minimal instrument modification. Surface-abraded Teflon tubing provided the solid support for sample collection and desorption. Performance was characterized by desorption efficiency, reproducibility, linearity of the calibration, and method detection and quantitation limits. Method validation was performed with a series of dinitrotoluenes, trinitrotoluene, two nitroester explosives, and one nitramine explosive. The method was applied to the sampling of a single piece of debris from an explosion containing trinitrotoluene.