过氧化丙酮类炸药的检测方法研究进展

恐怖袭击是当今世界安全的重大隐患之一,过氧化物炸药因其难以被常规手段检测的特点常被不法分子使用,其中过氧化丙酮类炸药是恐怖分子常用的爆炸物质.本文主要简述了近20年来关于过氧化丙酮类炸药的不同检测方法,主要包括传统检测技术如荧光检测技术和质谱、色谱、拉曼光谱等波谱技术以及基于电化学法、化学比色法、物理传感器和生物免疫的...     

Highly sensitive electrochemical detection of trace liquid peroxide explosives at a Prussian-blue 'artificial-peroxidase' modified electrode

A highly sensitive electrochemical assay of the peroxide-based explosives triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) at a Prussian-blue (PB) modified electrode is reported. The method involves photochemical degradation of the peroxide explosives and a low potential (0.0 V) electrocatalytic amperometric sensing of the generated hydrogen peroxide at the PB transducer and offers nanomolar detection limits following a short (15 s) irradiation times. The electrochemical sensing protocol should facilitate rapid field screening of peroxide explosives.     

Rapid screening of explosives in ambient environment by aerodynamic assisted thermo desorption mass spectrometry

Rapid, direct, and trace detection of explosives in an open environment is of particular need in homeland and/or transportation security. In this work, an aerodynamic assisted thermo desorption mass spectrometry method was developed for the direct quantitative analyses of explosives from a distance. Remote non‐volatile explosive sensing was achieved for 2, 4, 6‐trinitrotoluene, trinitrohexahydro‐1, 3, 5‐triazine, 8701 (main ingredient: RDX 98.5%), and C4 (a type of plastic explosive) with a distance of 0.65 m. Furthermore, a close to 324 cm² effective sampling area could be achieved, and the limits of detection are in the ng range. This device can be deployed in airports and subway stations for high‐throughput and automatic luggage/personnel screening of prohibited articles, such as explosives and illicit drugs. Copyright © 2016 John Wiley & Sons, Ltd.     

A review of biosensors and biologically-inspired systems for explosives detection

This article provides a review of the published literature describing the use of biosensors and biologically-inspired systems for explosives detection. The review focusses on the use of antibodies, enzymes, biologically-inspired synthetic ligands and whole-cell biosensors, providing a flavour of the range of technology, formats and approaches that can be used to detect explosives using biological systems.     

Non-aerosol detection of explosives with a continuous flow immunosensor

Contamination of groundwater, soil, and the marine environment by explosives is a global issue. Identification, characterization and remediation are all required for a site recognized as contaminated with 2,4,6-trinitrotoluene (TNT) or hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). For each step, a method to accurately measure the contaminant level is needed. This paper reviews some of the current methods with emphasis on a single biosensor developed in our laboratory. Current regulatory methods require samples to be sent off-site to a certified laboratory resulting in time delays up to a month. A continuous flow biosensor for detection of explosives has been developed and tested for the rapid field screening of environmental samples. The detection system is based on a displacement immunoassay in which monoclonal antibodies to (TNT) and RDX are immobilized on solid substrates, allowed to bind fluorescently labeled antigens, and then exposed to explosives in aqueous samples. Explosive compounds present in the sample displace proportional amounts of the fluorescent label, which can then be measured to determine the original TNT or RDX concentration. The system can accurately detect ppb to ppt levels of explosives in groundwater or seawater samples and in extracts of contaminated soil. The biosensor has applications in environmental monitoring at remediation sites or in the location of underwater unexploded ordnance.     

Ultrasensitive detection of aliphatic nitro-organics based on “turn-on” fluorescent sensor array

The broad class of explosives includes nitro aromatics as well as challenging aliphatic nitro-organics whose detection is important from counter-terrorism and national security perspectives. Here we report a turn-on fluorescent sensor array based on aggregation-induced emission (AIE) fluorophores as receptors. To achieve a good sensing system with fast response, good sensitivity and low detection limit, three receptors with abundant chemical diversities for target analytes were synthesized. The turn-on response of the individual receptor showed highly variable and cross-reactive analyte-dependent changes in fluorescence. The excellent ability to identify a variety of explosives, especially the challenging aliphatic nitro-organics (2,3-dimethyl-2,3-dinitrobutane (DMNB), 1,3,5-trinitro-1,3,5-triazinane (RDX), cyclotetramethylene tetranitramine (HMX) and entaerythritol tetranitrate (PETN)), was demonstrated in qualitative and quantitative analyses with 100% accuracy. The fluorescence signal amplification in the presence of explosives allows for application of these receptors in a sensor microarray suitable for high-throughput screening. These results suggested that the cross-reactive sensor array based on AIE fluorophores could find a wide range of applications for sensing various analytes or complex mixtures.     

Formation of charges of plastic industrial explosives by extrusion

Principles of application of extrusion technology for the formation of charges of industrial plastic explosives are considered, including analysis of extruder operation and modeling of extrusion process.     

Environmental monitoring approaches used during bioremediation of soils contaminated with hazardous explosive chemicals

Defense sites are contaminated with explosives, which are released during manufacturing, firing, testing and training operations; loading, assembly and packing activities; and demilitarization operations. Explosive chemicals are hazardous in nature. Contamination of the soil and the underlying groundwater by explosives pose serious threat to human and animal health and the eco-system. Bioremediation is an eco-friendly technology as it exploits nature’s own agents- the microbes in degrading the contaminant of interest. This waste treatment technology has been extensively studied for degrading the explosive pollutant. Environmental monitoring, a process of systematic collection of data and analysis is essential in performance evaluation of any waste treatment system. This paper gives a comprehensive overview on the environmental monitoring approaches used during bioremediation of explosives contaminated soil. Biogeochemical factors viz., presence and survivability of microbes, bioavailability of the contaminant, pH, temperature, moisture content, redox conditions, presence/addition of substrate and nutrients and presence of intermediates/co-contaminants in the soil environment that are reported to affect the bioremediation of explosives are highlighted. Details on physical, chemical and biological parameters monitored during bioremediation are included. Advancements in instrumental techniques are evolving rapidly and its application in bioremediation approaches promise an enhanced understanding of the mineralization of explosive in the soil environment. Recent developments in application of advanced analytical instrumentation techniques, future research insights with recommendations, which will illuminate the selection of appropriate monitoring tool for evaluating bioremediation are also summarized.     

A critical review of ion mobility spectrometry for the detection of explosives and explosive related compounds

Ion mobility spectrometry has become the most successful and widely used technology for the detection of trace levels of nitro-organic explosives on handbags and carry on-luggage in airports throughout the US. The low detection limits are provided by the efficient ionization process, namely, atmospheric pressure chemical ionization (APCI) reactions in negative polarity. An additional level of confidence in a measurement is imparted by characterization of ions for mobilities in weak electric fields of a drift tube at ambient pressure. Findings from over 30 years of investigations into IMS response to these explosives have been collected and assessed to allow a comprehensive view of the APCI reactions characteristic of nitro-organic explosives. Also, the drift tube conditions needed to obtain particular mobility spectra have been summarized. During the past decade, improvements have occurred in IMS on the understanding of reagent gas chemistries, the influence of temperature on ion stability, and sampling methods. In addition, commercial instruments have been refined to provide fast and reliable measurements for on-site detection of explosives. The gas phase ion chemistry of most explosives is mediated by the fragile CONO(2) bonds or the acidity of protons. Thus, M(-) or M.Cl(-) species are found with only a few explosives and loss of NO(2), NO(3) and proton abstraction reactions are common and complicating pathways. However, once ions are formed, they appear to have stabilities on time scales equal to or longer than ion drift times from 5-20 ms. As such, peak shapes in IMS are suitable for high selectivity and sensitivity.     

High-throughput walkthrough detection portal for counter terrorism: detection of triacetone triperoxide (TATP) vapor by atmospheric-pressure chemical ionization ion trap mass spectrometry

With the aim of improving security, a high‐throughput portal system for detecting triacetone triperoxide (TATP) vapor emitted from passengers and luggage was developed. The portal system consists of a push‐pull air sampler, an atmospheric‐pressure chemical ionization (APCI) ion source, and an explosives detector based on mass spectrometry. To improve the sensitivity of the explosives detector, a novel linear ion trap mass spectrometer with wire electrodes (wire‐LIT) is installed in the portal system. TATP signals were clearly obtained 2 s after the subject under detection passed through the portal system. Preliminary results on sensitivity and throughput show that the portal system is a useful tool for preventing the use of TATP‐based improvised explosive devices by screening persons in places where many people are coming and going. Copyright © 2011 John Wiley & Sons, Ltd.     

A method for detecting explosives

Bombs concealed in luggage have threatened human life and property throughout the world's traffic. The plastic explosives could not be checked by the X-ray detecting device. A method has been tested in the present work for non-destructive detection of explosives. A neutron generator and relevant apparatus have been used as a tool to find explosives, regardless of the bomb's shape and the packing materials. It seems that this method is a promising one because of the strong transmission ability of both the incident and output specific radiations and low background.     

Study of initiation reactivity of some plastic explosives by vacuum stability test and non-isothermal differential thermal analysis

On the basis of measurements of 18 high explosives by means of the Czech Vacuum Stability Test (VST) STABIL, a relationship has been specified between the results of this test and those of Russian manometric method. The said relationship was used to predict the Arrhenius parameters (E_a and log A values) of four plastic explosives based on RDX and one high explosive based on PETN (Semtex). The slopes E_aR⁻¹ of Kissinger's equation were specified by means of non-isothermal differential thermal analysis (DTA) and evaluation of the measurement results by means of the Kissinger method. The role played by binders and plasticizers in thermal decomposition of nitramines was pointed out on the basis of relationship between the E_a values obtained from VST and the E_aR⁻¹ values obtained from DTA, both for plastic explosives, eight nitramines, Composition B and PETN. The relationships between the E_aR⁻¹ values and thermostability threshold was specified for the given group of explosives. The relationship classify some of the studied plastic explosives as belonging to nitramines with steric hindrance in the molecule (CPX, TNAZ and HNIW). The relationship between E_aR⁻¹ values and drop energies, E_dr, sharply differentiates between plastic explosives and individual nitramines. From the relationship between the E_dr and D² values it was found that the increasing performance of the studied nitramines and plastic explosives is connected with the decrease in their impact sensitivity. Also specified are the approximate linear dependences between the peak temperatures of exothermic decomposition of all the explosives studied and their ignition temperatures, T_ig, or critical temperatures, T_c; these dependences were applied to prediction of T_ig and T_c of both the studied plastic explosives and some of the nitramines.     

Combined time- and space-resolved Raman spectrometer for the non-invasive depth profiling of chemical hazards

A time-resolved inverse spatially offset Raman spectrometer was constructed for depth profiling of Raman-active substances under both the lab and the field environments. The system operating principles and performance are discussed along with its advantages relative to traditional continuous wave spatially offset Raman spectrometer. The developed spectrometer uses a combination of space- and time-resolved detection in order to obtain high-quality Raman spectra from substances hidden behind coloured opaque surface layers, such as plastic and garments, with a single measurement. The time-gated spatially offset Raman spectrometer was successfully used to detect concealed explosives and drug precursors under incandescent and fluorescent background light as well as under daylight. The average screening time was 50 s per measurement. The excitation energy requirements were relatively low (20 mW) which makes the probe safe for screening hazardous substances. The unit has been designed with nanosecond laser excitation and gated detection, making it of lower cost and complexity than previous picosecond-based systems, to provide a functional platform for in-line or in-field sensing of chemical substances.     

Fabric analysis by ambient mass spectrometry for explosives and drugs

Desorption electrospray ionization (DESI) is applied to the rapid, in-situ, direct qualitative and quantitative analysis of mixtures of explosives and drugs from a variety of fabrics, including cotton, silk, denim, polyester, rayon, spandex, leather and their blends. The compounds analyzed were 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 the drugs of abuse: heroin, cocaine, and methamphetamine. Limits of detection are in the picogram range. DESI analyses were performed without sample preparation and carried out in the presence of common interfering chemical matrices, such as insect repellant, urine, and topical lotions. Spatial and depth profiling was investigated to examine the depth of penetration and lateral resolution. DESI was also used to examine cotton transfer swabs used for travel security sample collection in the screening process. High throughput quantitative analysis of fabric surfaces for targeted analytes is also reported.     

Sensitive Voltammetric Sensing of the 2,3‐Dimethyl‐2,3‐dinitrobutane (Dmnb) Explosive Taggant

The highly sensitive voltammetric detection of the 2,3‐dimethyl‐2,3‐dinitrobutane (DMNB), a required additive to commercial plastic explosives, is described. The protocol relies on a fast square‐wave voltammetric measurement of the DMNB explosive taggant at an unmodified carbon fiber electrode using a phosphate buffer (pH 7.0) solution. Different solutions and working electrodes were evaluated. Under the optimal conditions, a linear response is observed over the 300–3000 μg/L DMNB concentration range examined, with a detection limit of 60 μg/L. A highly stable response, with a relative standard deviation (RSD) of 2.6%, is observed for 30 repetitive measurements. Such electrochemical approach offers great promise for a simple, rapid, sensitive and inexpensive field screening of plastic explosives. Preliminary data illustrate the utility of electrochemical detection for electrophoretic microchips for the simultaneous measurements of DMNB, cyclotrimethylenetrinitramine (RDX) and pentaerythritoltetranitrate (PETN).     

Screening people for illicit substances: a survey of current portal technology

The need to implement more effective, cost efficient, non-intrusive ways of screening people for concealed drugs, explosives and weapons is a major security initiative for the U.S. and elsewhere. A new generation of portals suitable for security checkpoints is under development. These will be able to find contraband with high probabilities of detection, and low false-alarm rates. Some portals image the body using either low dose X-rays or millimeter wave interrogation, and analyze the radiation back-scattered from the body, providing images of concealed objects. Other portals operate essentially as anomaly detectors, finding objects on the human body. A series of portals is also under development that can harvest and analyze vapors or particles of the contraband substances. Some of the issues surrounding portal development include perceived safety issues, privacy issues, and operational issues such as ease of operation, non-invasiveness, and ease of interpretation. It is believed that portal technology will mature, and the cost of portals will fall sufficiently to make widespread deployment of portals at security checkpoints a reality within the next decade.     

Theoretical studies of energy transfer rates of secondary explosives

Understanding the mechanism of shock-induced chemical reaction in secondary explosives is necessary to pursue the development and the safe use of new explosives having high performance and low sensitivity. In an effort to understand the mechanism, the energy transfer rates of such secondary explosives as PETN(I), PETN(II), delta-HMX, alpha-HMX, beta-HMX, RDX, ANTA, DMN, and NM have been evaluated based on the formula derived by Fried and Ruggiero [Fried, L. E.; Ruggiero, A. J. J. Phys. Chem. 1994, 98, 9786]. The energy transfer rates were determined in terms of the density of vibrational states and the unharmonic vibron-phonon coupling term, which were calculated by using a flexible potential containing both intra- and intermolecular terms. For the secondary explosives, a good correlation was found between the energy transfer rates and the impact sensitivity. The energy transfer rates are several times faster for the explosives with higher sensitivity such as PETN, HMX, and RDX than those with lower sensitivity such as ANTA, DMN, and NM. The calculations presented suggest the energy transfer rate in secondary explosive crystals is a significant factor in their sensitivity and introduction of double bond, or hydrogen bonds, or caged structure into secondary explosives is expected to decrease the sensitivity.     

Determination of explosives in environmental water samples by solid-phase microextraction-liquid chromatography

When explosives are present in natural aqueous media, their concentration is usually limited to trace levels. A preconcentration step able to remove matrix interferences and to enhance sensitivity is therefore necessary. In the present study, we evaluated solid-phase microextraction (SPME) technique for the recovery of nine explosives from aqueous samples using high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Several parameters, including adsorption and desorption time, coating type, rate of stirring, salt addition, and pH, were optimized to obtain reproducible data with good accuracy. Carbowax coating was the only adsorbent found capable of adsorbing all explosives including nitramines. Method detection limits (MDL) were found to range from 1 to 10 microg/L, depending on the analyte. SPME/HPLC-UV coupling was then applied to the analysis of natural ocean and groundwater samples and compared to conventional solid-phase extraction (SPE/HPLC-UV). Excellent agreement was observed between both techniques, but with an analysis time around five times shorter, SPME/HPLC-UV was considered to be applicable for quantitative analysis of explosives.     

Micellar electrokinetic chromatography and capillary electrochromatography of nitroaromatic explosives in seawater

The ability to separate nitroaromatic and nitramine explosives in seawater sample matrices is demonstrated using both MEKC and CEC. While several capillary-based separations exist for explosives, none address direct sampling from seawater, a sample matrix of particular interest in the detection of undersea mines. Direct comparisons are made between MEKC and CEC in terms of sensitivity and separation efficiency for the analysis of 14 explosives and explosive degradation products in seawater and diluted seawater. The use of high-salt stacking with MEKC results, on average, in a three-fold increase in the number of theoretical plates, and nearly double resolution for samples prepared in 25% seawater. By taking advantage of long injection times in conjunction with stacking, detection limits down to sub mg/L levels are attainable; however, resolution is sacrificed. CEC of explosive mixtures using sol-gels prepared from methyltrimethoxysilane does not perform as well as MEKC in terms of resolving power, but does permit extended injection times for concentrating analyte onto the head of the separation column with little or no subsequent loss in resolution. Electrokinetic injections of 8 min at high voltage allow for detection limits of explosives below 100 microg/L.     

"One-step" simplified electrochemical sensing of TATP based on its acid treatment

A fast, simple and sensitive electrochemical method for sensing peroxide-based explosives based on their acid treatment is reported. The method relies on the high electrocatalytic activity of Prussian-blue (PB)-modified electrodes towards the acid-generated hydrogen peroxide in the harsh acidic medium (down to pH 0.3) used for releasing hydrogen peroxide. Such effective operation of PB electrochemical sensors in strongly acidic media eliminates the need for an additional neutralization step required in analogous peroxidase-based assays (due to acid-induced enzyme deactivation processes). Factors affecting the efficiency of the acid pre-treatment of triacetone triperoxide (TATP) have been examined and optimized to allow its sensitive measurement down to the 50 ng level within 60 s. Chronoamperometric detection of microgram amounts of solid TATP, following a one-minute acid mixing and placing a 20 microL droplet onto a disposable PB-modified screen-printed electrode is illustrated. Similar results were obtained for the peroxide explosive hexamethylene triperoxide diamine (HMTD). By greatly simplifying the analytical procedure, such an acid-operated "artificial peroxidase" electrocatalytic transducer holds great promise for designing "one-step", user-friendly, miniaturized, cost-effective devices for field screening of peroxide explosives.