Recent methods for the determination of peroxide-based explosives

A Benzil- and BODIPY-Based Turn-On Fluorescent Probe for Detection of Hydrogen Peroxide

Faced with rising threats of terrorism, environmental and health risks, achieving sensitive and selective detection of peroxide-based explosives (PEs) has become a global focus. In this study, a turn-on fluorescent probe (BOD) based on benzil (H2O2-recognition element) and 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivative (fluorophore) was developed to sensitively and specifically detect hydrogen peroxide (H2O2). The synthesized BOD had a very weak fluorescence due to intramolecular donor-excited photo-induced electron transfer (d-PET) effect; however, it could emit a strong fluorescence since H2O2 selectively oxidized the benzil moiety and released free BODIPY fluorophore (BOD-COOH). As a result, the proposed BOD detected H2O2 in linear detection ranged from 25 to 125 µM with a detection limit of 4.41 µM. Meanwhile, the proposed BOD showed good selectivity toward H2O2, which is not affected by other common reactive oxygen species (ROS) and ions from explosive residues. In addition, a blue shift from 508 to 498 nm was observed in the absorption spectra upon addition of H2O2. More importantly, the BOD was successfully applied for rapid detection of H2O2 vapor with good sensitivity (down to 7 ppb), which holds great potential for practical use in public safety, forensic analysis and environmental monitoring.

Stationary Explosive Trace Detection System Using Differential Ion Mobility Spectrometry (DMS)

Detecting trace amounts of explosives is important for maintaining national security due to the growing threat of terror attacks. Particularly challenging is the increasing use of homemade explosives. Therefore, there is a constant need to improve existing technologies for detecting trace amounts of explosives. This paper describes the design of a stationary device (a gate) for detecting trace amounts of explosives and explosive taggants and the design of differential ion mobility spectrometers with a focus on the gas system. Nitromethane (NM), trimeric acetone peroxide (TATP), hexamine peroxide (HMTD), and explosive taggants 2,3-dimethyl-2,3-dinitrobutane (DMDNB) and 4-nitrotoluene (4NT) were used in this study. Gate measurements were carried out by taking air from the hands, pocket area, and shoes of the tested person. Two differential ion mobility spectrometers operating in two different modes were used as explosive detectors: a mode with a semi-permeable membrane to detect explosives with high vapor pressures (such as TATP) and a mode without a semi-permeable membrane (using direct introduction of the sample into the measuring chamber) to detect explosives with low vapor pressures (such as HMTD). The device was able to detect trace amounts of selected explosives/explosive taggants in 5 s.

Recent development and trends in the detection of peroxide-based explosives

Peroxide-based explosives (PBEs) are increasingly common in criminal and terrorist activity due to their easy synthesis and high explosive power. The rise in terrorist attacks involving PBEs has heightened the importance of detecting trace amounts of explosive residue or vapors. This paper aims to provide a review on the developments of techniques and instruments for detecting PBEs over the past ten years, specifically discussing advancements in ion mobility spectrometry, ambient mass spectrometry, fluorescence techniques, colorimetric methods, and electrochemical methods. We provide examples to illustrate their evolution and focus on new strategies for improving detection performance, specifically in terms of sensitivity, selectivity, high-throughput, and wide explosives coverage. Finally, we discuss future prospects for PBE detection. It is hoped this treatment will serve as a guide to the novitiate and as aid memoire to the researchers.

Thiolated gamma-cyclodextrin-polymer-functionalized CeFe3O4 magnetic nanocomposite as an intrinsic nanocatalyst for the selective and ultrasensitive colorimetric detection of triacetone triperoxide

Explosives are powerful destructive weapons used by criminals and terrorists across the globe and their use within military installation sites poses serious environmental health problems. Existing colorimetric sensors for triacetone triperoxide (TATP) relies on detecting its hydrolysed H₂O₂ form. However, such detection strategy limits the practicability for on-site TATP sensing. In this work, we have developed a novel peroxidase mimic catalytic colorimetric sensor for direct recognition of TATP. Ceria (Ce)-doped Fe₃O₄ nanoparticles (CeFe₃O₄) were synthesized via the hot-injection organic synthetic route in the presence of metal precursors and organic ligands. Thereafter, the organic-capped CeFe₃O₄ nanoparticles were surface-functionalized with amphiphilic polymers (Amp-poly) to render the nanoparticle stable, compact and biocompatible. Thiolated γ-cyclodextrin (γ-CD) was adsorbed on the Amp-poly-CeFe₃O₄ nanocomposite (NC) surface to form a γ-CD-Amp-poly-CeFe₃O₄ NC. γ-CD served both as a receptor and as a catalytic enhancer for TATP. Hemin (H), used as a catalytic signal amplifier was adsorbed on the γ-CD-Amp-poly-CeFe₃O₄ NC surface to form a γ-CD-Amp-poly-CeFe₃O₄-H NC that served as a functional nanozyme for the enhanced catalytic colorimetric detection of TATP. Under optimum experimental reaction conditions, TATP prepared in BIS-TRIS-Trisma Ac-KAc-NAc buffer, pH 3, was selectively and ultrasensitively detected without the need for acid hydrolysis based on the catalytic oxidation of 3,3',5,5'-tetramethylbenzidine by H₂O₂ in the presence of the γ-CD-Amp-poly-CeFe₃O₄-H hybrid nanozyme. The obtained limit of detection of ∼0.05 μg/mL when compared with other published probes demonstrated superior sensitivity. The developed peroxidase mimic γ-CD-Amp-poly-CeFe₃O₄-H catalytic colorimetric sensor was successfully applied to detect TATP in soil, river water and tap water samples.

Mechanochemical synthesis of an AIE-TICT-ESIPT active orange-emissive chemodosimeter for selective detection of hydrogen peroxide in aqueous media and living cells, and solid-phase quantitation using a smartphone

We report herein the design and mechanochemical synthesis of a chemodosimeter, benzothiazole-derived unsymmetrical azine protected by 4-bromomethylphenylboronic acid (BTPAB), an orange aggregation-induced emission (AIE), for the selective detection of H2O2 in a turn-on manner.

Expeditious base-free solid-state reaction between phenyl boronates and hydrogen peroxide on silica gel

The expeditious base-free reaction between a phenyl boronate film and H2O2 vapor can be realized on a silica gel surface, playing an important role in sensor manufacturing applications and chemical production.

Direct Electrochemical Determination of Peroxide-Type Explosives Using Well-Dispersed Multi-Walled Carbon Nanotubes/Polyethyleneimine-Modified Glassy Carbon Electrodes

The sensitive and selective determination of peroxide-based explosives (PBEs) in the field/on site is an important analytical challenge. Most methods claiming to detect PBEs are indirect, actually detecting their decomposition product, H₂O₂. Here, we present an electrochemical sensor for direct detection of organic peroxide explosives, that is, triacetone triperoxide (TATP) and hexamethylenetriperoxide diamine (HMTD), using well-dispersed multiwalled carbon nanotubes/polyethyleneimine (MWCNTs/PEI)-modified glassy carbon (GC) electrode, namely, GC/MWCNTs/PEI electrode. This is the first use of the conductive polyelectrolyte PEI as an electrode modifier for pristine PBE sensing. The potential range, scan rate, solvent selection, and supporting electrolyte concentration were optimized for PBEs. As a distinct advantage over other similar methods, our sensor electrode responded to intact TATP solutions in neutral medium, meaning that TATP did not interact with acids/bases that would transform it into H₂O₂. Calibration curves were linear in the range of 10-200 mg L^-1 for TATP and 25-200 mg L^-1 for HMTD. Using differential pulse voltammetry, detection limits of 1.5 mg L^-1 TATP and 3.0 mg L^-1 HMTD were obtained from direct electrochemical reduction in 80/20% (v/v) H₂O-acetone solvent medium. Electroactive camouflage materials such as passenger belongings (e.g., sweetener, detergent, sugar, and paracetamol-caffeine-based analgesic drugs), common ions, and other explosives were shown not to interfere with the proposed method. The nonresponsive behavior of our electrode to H₂O₂ prevents "false positives" from other peroxide materials of everyday use. This electrochemical sensor could also detect other nitro-explosives at different potentials and was statistically validated against standard GC-MS and spectrophotometric methods.

Detection of Triacetone Triperoxide (TATP) and Hexamethylene Triperoxide Diamine (HMTD) from the Gas Phase with Differential Ion Mobility Spectrometry (DMS)

One of the significant problems in the modern world is the detection of improvised explosives made of materials synthesized at home. Such compounds include triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD). An attempt was made to construct an instrument allowing for the simultaneous detection of both compounds despite the large difference of vapor pressure: very high for TATP and very low for HMTD. The developed system uses differential ion mobility spectrometry (DMS) in combination with a specially designed gas sample injection system. The created system of detectors allowed for the detection of a high concentration of TATP and a very low concentration of HMTD. TATP detection was possible despite the presence of impurities—acetone remaining from the technological process and formed as a coproduct of diacetone diperoxide (DADP) synthesis. Ammonia added to the carrier gas improved the possibility of detecting the abovementioned explosives, reducing the intensity of the acetone signal. The obtained results were then compared with the detection capabilities of drift tube ion mobility spectrometer (DT-IMS), which has not made possible such detection as DMS.

Selective dual detection of Hg2+ and TATP based on amphiphilic conjugated polythiophene-quantum dot hybrid materials

The design of multifunctional sensors based on biocompatible hybrid materials consisting of conjugated polythiophene-quantum dots for multiple environmental pollutants is a promising strategy for the development of new monitoring technologies. Herein, we present a new approach for the "on-off-on" sensing of Hg²⁺ and triacetone triperoxide (TATP) based on amphiphilic polythiophene-coated CdTe QDs (PQDs, PLQY ∼78%). The emission of the PQDs is quenched by Hg²⁺ ions via electron transfer interactions. Based on the strong interaction between TATP and Hg²⁺ ions, the addition of TATP to the PQD-Hg²⁺ complex results in a remarkable recovery of the PQD emission. Under the optimized conditions, the PQD sensor shows a good linear response to Hg²⁺ and TATP with detection limits of 7.4 nM and 0.055 mg L^-1, respectively. Furthermore, the "on-off-on" sensor demonstrates good biocompatibility, high stability, and excellent selectivity in the presence of other metal ions and common explosives. Importantly, the proposed method can be used to determine the level of Hg²⁺ and TATP in environmental water samples.

Detection of hydrogen peroxide using dioxazaborocanes: elucidation of the sensing mechanism at the molecular level by NMR and XPS measurements

The H₂O₂vapour cleaves the N–B bond and inhibits the fluorescence of the dixazaborocane.

Titanium dioxide nanoparticles-based colorimetric sensors for determination of hydrogen peroxide and triacetone triperoxide (TATP)

Due to its relatively simple preparation and readily available precursors, determination of triacetone triperoxide (TATP) by portable devices has become important. In this work, two different titanium dioxide nanoparticles (TiO₂NPs)-based colorimetric sensors based on complex formation on the solid surface were developed for determination of H₂O₂ and TATP. The first sensor, (3-aminopropyl)triethoxysilane (APTES) modified-TiO₂NPs-based paper sensor (APTES@TiO₂NPs), exploits peroxo-titanate binary complex formation between APTES@TiO₂NPs and H₂O₂ on chromatographic paper. The second sensor, 4-(2-pyridylazo)-resorcinol-modified-TiO₂NPs-based solid sensor (PAR@TiO₂NPs), relies on the formation of a ternary complex between Ti(IV), PAR and H₂O₂. The developed sensors were also applied to TATP determination after acidic hydrolysis of samples to H₂O₂. The limits of detection (LODs) of APTES@TiO₂NPs-based paper sensor were 3.14 × 10^-4 and 5.13 × 10^-4 mol L^-1 for H₂O₂ and TATP, respectively, whereas the LODs of PAR@TiO₂NPs solid sensor were 6.06 × 10^-7 and 3.54 × 10^-7 mol L^-1 for H₂O₂ and TATP, respectively. Possible interferences of common soil ions, passenger belongings used as camouflage materials during public transport (e.g., detergent, sweetener, acetylsalicylic acid and paracetamol-caffeine based analgesic drugs) and of other explosives were examined. The developed methods were statistically validated using t- and F- tests against the titanyl sulfate (TiOSO₄) colorimetric literature method.

Novel synthesis of a Cu2O–graphene nanoplatelet composite through a two-step electrodeposition method for selective detection of hydrogen peroxide

Optimized electrodeposition technique for the synthesis of Cu₂O–graphene composite for H₂O₂sensing.

Electronic Tongue-A Tool for All Tastes?

Electronic tongue systems are traditionally used to analyse: food products, water samples and taste masking technologies for pharmaceuticals. In principle, their applications are almost limitless, as they are able to almost completely reduce the impact of interferents and can be applied to distinguish samples of extreme complexity as for example broths from different stages of fermentation. Nevertheless, their applications outside the three principal sample types are, in comparison, rather scarce. In this review, we would like to take a closer look on what are real capabilities of electronic tongue systems, what can be achieved using mixed sensor arrays and by introduction of biosensors or molecularly imprinted polymers in the matrix. We will discuss future directions both in the sense of applications as well as system development in the ever-growing trend of low cost analysis.

Color manipulation through microchip tinting for colorimetric detection using hue image analysis

Colorimetry with microfluidic devices has been proven to be an advantageous method for in situ analyses where limited resources and rapid response for untrained users are desired. Image analysis using a small camera or cell phone can be easily incorporated for an objective readout, eliminating variations from normal differences in color perception and environmental factors during analysis. The image analysis using the parameter hue, for example, has been utilized as a highly effective, objective analysis method that correlates with the psychological way color is perceived. Hue analysis, however, is best used for colorimetric reactions that result in distinct changes from one color to a markedly different color and can be inadequate to distinguish between subtle or monotonal (colorless-to-colored) color changes. We address this with three unique color manipulation (i.e., tinting) techniques that provide greater discrimination with such color changes, thus yielding improved limits of detection for various colorimetric reactions that may have previously been limited. Tinting is invoked through dyeing the reagent substrate, colored printing the device, or colored lighting during image capture, and is shown to effectively shift the background color of the reaction detection area. Hydrogen peroxide, a constituent of peroxide-based explosives, is associated with a monochromatic color change upon reaction, and this is used to demonstrate the effectiveness of the tinting methods in improving the limit of detection from an undetectable color change to 0.1 mg mL^-1.

Design, synthesis and properties of a reactive chromophoric/fluorometric probe for hydrogen peroxide detection

A succinct chromophoric/fluorometric probe, AVPM, for sensitive and selective H₂O₂detection.

Colorimetric Sensor Arrays for the Detection and Identification of Chemical Weapons and Explosives

There is a significant demand for devices that can rapidly detect chemical–biological–explosive (CBE) threats on-site and allow for immediate responders to mitigate spread, risk, and loss. The key to an effective reconnaissance mission is a unified detection technology that analyzes potential threats in real time. In addition to reviewing the current state of the art in the field, this review illustrates the practicality of colorimetric arrays composed of sensors that change colors in the presence of analytes. This review also describes an outlook toward future technologies, and describes how they could possibly be used in areas such as war zones to detect and identify hazardous substances.

Electronic tongue for nitro and peroxide explosive sensing

This work reports the application of a voltammetric electronic tongue (ET) towards the simultaneous determination of both nitro-containing and peroxide-based explosive compounds, two families that represent the vast majority of compounds employed either in commercial mixtures or in improvised explosive devices. The multielectrode array was formed by graphite, gold and platinum electrodes, which exhibited marked mix-responses towards the compounds examined; namely, 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), pentaerythritol tetranitrate (PETN), 2,4,6-trinitrotoluene (TNT), N-methyl-N,2,4,6-tetranitroaniline (Tetryl) and triacetone triperoxide (TATP). Departure information was the set of voltammograms, which were first analyzed by means of principal component analysis (PCA) allowing the discrimination of the different individual compounds, while artificial neural networks (ANNs) were used for the resolution and individual quantification of some of their mixtures (total normalized root mean square error for the external test set of 0.108 and correlation of the obtained vs. expected concentrations comparison graphs r>0.929).

Enhanced electrospray ionization mass spectrometric detection of hexamethylene triperoxide diamine (HMTD) after oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD)

RATIONALE

Hexamethylene triperoxide diamine (HMTD) is one of the peroxide-based explosives that are difficult to detect using standard analytical methodologies.

METHODS

It was analyzed by electrospray ionization mass spectrometry (ESI-MS) on a UPLC-TOF instrument. Alkali metal salts were used to promote the formation of ions.

RESULTS

In the full scan positive ion mode a 3 ng (13 pmol) limit of detection was achieved if [HMTD + Me](+) ions (Me = Li, Na, K) were detected. It was found that HMTD easily undergoes oxidation to tetramethylene diperoxide diamine dialdehyde (TMDDD) in the source as well as in the samples. TMDDD can be detected as [TMDDD + Me](+) ions, but better ionization efficiency leads to the detection limit of TMDDD at the 2 pg (0.01 pmol) level. In butyl acetate the yield of oxidation of HMTD to TMDDD reaches 25% within 20 min at 120 °C, which offers a simple way of improving the detection limit of HMTD by two orders of magnitude.

CONCLUSIONS

A simple procedure of detection of HMTD that matches the most sensitive methods available was developed. It uses standard equipment available in many laboratories. It was shown that the frequently reported [HMTD-H](+) cation observed by various authors was in fact a misinterpretation of the results, and should be attributed to [TMDDD + H](+).

Borate ester endcapped fluorescent hyperbranched conjugated polymer for trace peroxide explosive vapor detection

The hyperbranched polymer S1/ZnO nanorod array composite is very promising for a highly sensitive fluorescence device for detecting peroxide explosives.

Hierarchical supramolecules and organization using boronic acid building blocks

Current progress on hierarchical supramolecules using boronic acids has been highlighted in this feature article. The feasibility of the structure-directing ability is fully discussed from the standpoint of the generation of new smart materials.

Development of a molecularly imprinted polymer-based sensor for the electrochemical determination of triacetone triperoxide (TATP)

The explosive triacetone triperoxide (TATP), which can be prepared from commercially readily available reagents following an easy synthetic procedure, is one of the most common components of improvised explosive devices (IEDs). Molecularly-imprinted polymer (MIP) electrochemical sensors have proved useful for the determination of different compounds in different matrices with the required sensitivity and selectivity. In this work, a highly sensitive and selective molecularly imprinted polymer with electrochemical capabilities for the determination of TATP has been developed. The molecular imprinting has been performed via electropolymerisation onto a glassy carbon electrode surface by cyclic voltammetry from a solution of pyrrole functional monomer, TATP template and LiClO4. Differential Pulse Voltammetry of TATP, with LiClO4 as supporting electrolyte, was performed in a potential range of -2.0 V to +1.0 V (vs. Ag/AgCl). Three-factor two-level factorial design was used to optimise the monomer concentration at 0.1 mol∙L(-1), template concentration at 100 mmol∙L(-1) and the number of cyclic voltammetry scan cycles to 10. The molecularly imprinted polymer-modified glassy carbon electrode demonstrated good performance at low concentrations for a linear range of 82-44,300 µg∙L(-1) and a correlation coefficient of r(2) = 0.996. The limits of detection (LoD) and quantification (LoQ) achieved were 26.9 μg∙L(-1) and 81.6 μg∙L(-1), respectively. The sensor demonstrated very good repeatability with precision values (n = 6, expressed as %RSD) of 1.098% and 0.55% for 1108 and 2216 µg∙L(-1), respectively. It also proved selective for TATP in the presence of other explosive substances such as PETN, RDX, HMX, and TNT.

Fluorescence ratiometric sensor for trace vapor detection of hydrogen peroxide

Trace vapor detection of hydrogen peroxide (H2O2) represents a practical approach to nondestructive detection of peroxide-based explosives, including liquid mixtures of H2O2 and fuels and energetic peroxide derivatives, such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), and hexamethylene triperoxide diamine (HMTD). Development of a simple chemical sensor system that responds to H2O2 vapor with high reliability and sufficient sensitivity (reactivity) remains a challenge. We report a fluorescence ratiometric sensor molecule, diethyl 2,5-bis((((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)oxy)carbonyl)amino)terephthalate (DAT-B), for H2O2 that can be fabricated into an expedient, reliable, and sensitive sensor system suitable for trace vapor detection of H2O2. DAT-B is fluorescent in the blue region, with an emission maximum at 500 nm in the solid state. Upon reaction with H2O2, DAT-B is converted to an electronic "push-pull" structure, diethyl 2,5-diaminoterephthalate (DAT-N), which has an emission peak at a longer wavelength centered at 574 nm. Such H2O2-mediated oxidation of aryl boronates can be accelerated through the addition of an organic base such as tetrabutylammonium hydroxide (TBAH), resulting in a response time of less than 0.5 s under 1 ppm of H2O2 vapor. The strong overlap between the absorption band of DAT-N and the emission band of DAT-B enables efficient Förster resonance energy transfer (FRET), thus allowing further enhancement of the sensing efficiency of H2O2 vapor. The detection limit of a drop-cast DAT-B/TBAH film was projected to be 7.7 ppb. By combining high sensitivity and selectivity, the reported sensor system may find broad application in vapor detection of peroxide-based explosives and relevant chemical reagents through its fabrication into easy-to-use, cost-effective kits.

Porphyrin nanoassemblies via surfactant-assisted assembly and single nanofiber nanoelectronic sensors for high-performance H₂O₂ vapor sensing

Porphyrins are recognized as important π-conjugated molecules correlating supramolecular chemistry, nanoscience, and advanced materials science. So far, as their supramolecular nanoassemblies are addressed, most efforts focus on the photo- or opto-related subjects. Beyond these traditional subjects, it is strongly desired to develop advanced porphyrin nanoassemblies in some other new topics of paramount importance. By means of a surfactant-assisted assembly, we herein show that porphyrins of different central metal ions, 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (H2TPyP), zinc 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (ZnTPyP), and oxo-[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(IV) (TiOTPyP), could be organized to form irregular aggregates, short nanorods, and long yet straight nanofibers, respectively. Remarkably, in terms of an organic ribbon mask technique, we show that such long yet straight TiOTPyP nanofibers could be integrated into single nanofiber-based two-end nanoelectronics. Such simple nanodevices could serve as high-performance sensors of a satisfactory stability, reproducibility, and selectivity for an expeditious detection of vapor-phase H2O2. This provides a new alternative for a fast sensing of vapor-phase H2O2, which is currently an important issue in the fields of anti-terrorism, industrial healthcare, etc. In contrast to the traditional investigations focusing on the photo- or opto-related topics, our work endows porphyrin nanostructures with new opportunities as advanced nanomaterials in terms of portable yet high-performance nanoelectronic sensors, which is an issue of general concern in modern advanced nanomaterials.

Synthesis of a borylated boron–dibenzopyrromethene dye enabling the visual detection of H2O2 vapor

A boron–dibenzopyrromethene dye with a pinacolboryl group has been newly synthesized for the use as a reaction-based chemosensor. A TLC plate coated by the dye enables us to detect H₂O₂ vapor visually.

Direct electrochemistry of cytochrome c immobilized on a graphene oxide–carbon nanotube composite for picomolar detection of hydrogen peroxide

A new bionanocomposite electrode based on cytochrome c immobilized graphene oxide-multiwalled carbon nanotube is used to fabricate a highly selective and sensitive amperometric biosensor for the picomolar level detection of hydrogen peroxide which may find application in bioimaging and healthcare

Time-resolved, laser initiated detonation of TATP supports the previously predicted non-redox mechanism

Our previously reported computational study of the decomposition pathways of triacetone triperoxide (TATP), 1, predicted that unlike most energetic materials, which involve self-combustion of fuel and oxidants, 1 decomposes via a thermoneutral, non-redox pathway that involves entropy burst. These predictions are now corroborated by time-resolved monitoring of deflagration or detonation of 1 using a fast video camera following initiation by a short pulse focused laser beam. While a fireball always accompanies the explosion of 1 under air, the formation of a fireball is totally prevented under a nitrogen atmosphere. These observations indicate that combustion of the gaseous primary products occurs as a secondary event only in the presence of exogenous oxygen. The composition of the product mixture was found to depend on the experimental conditions. With long pulse focused laser beam (150 μs at 1064 nm) at either 210 or 110 mJ, the small amounts of charcoal needed for initiation suggest that the energy required to initiate 1 by pulse laser is 4-10 mJ, much smaller than the energy required for initiation by either mechanical stress or electric discharge. This time-resolved study highlights the very unusual properties of the peroxide based explosives.

Tetrathiafulvalene-capped hybrid materials for the optical detection of explosives

Mesoporous silica microparticles capped with TTF moieties and containing a ruthenium dye in the pores were used for the turn-on optical detection of the nitroaromatic explosives Tetryl and TNT via a selective pore uncapping and release of the entrapped dye.