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Central Forensic Science Laboratory, Government of India, 30, Gorachand Road, Kolkata-700 014, India E-mail : bagchiseema@gmail.com, sujitclahiri@yahoo.com Fax : 91-33-22849442 Geological Survey of India, Government of India, Kolkata-700 069, India E-mail : cashu@rediffmail.com Chemical Examination Laboratory, Excise Department, Government of West Bengal, Kolkata-700 046, India E-mail : kuiladk@rediffmail.com More than 1650 pre blast and post blast exhibits were analyzed using routine analytical procedures supplemented by advanced analytical techniques like Ion-Chromatography (IC) (mainly), Scanning Electron Microscope with Energy Dispersive X-ray Analyzer (SEM-EDXA), Fourier Transforms Infrared Spectroscopy (FTIR), Atomic Absorption Spectrometer (AAS) (for a number of samples) for inorganic constituents and High Performance Liquid Chromatography (HPLC), High Performance Thin Layer Chromatography (HPTLC), Gas Chromatograph-Mass Spectrometer (GC-MS), UV-Visible Spectrophotometer, Fourier Transform Infrared Spectroscope (FTIR), Liquid Chromatography-Tandem Mass Spetrometry (LC/MS/MS) for organic constituents. Results of the investigations suggested that high explosives like nitroglycerine, di and tri nitrotoluene (DNT and TNT), tetryl, cyclonite (RDX), pentaerythritol tetranitrate (PETN) were rarely used except in mortars and detonators. Common easily available unrestricted chemicals like potassium nitrate/ chlorate (KNO3/KClO3), arsenic sulphide (As2S3), sulphur, aluminium powder of different mesh size and sodium, calcium, magnesium, barium, strontium (Na+, Ca+, Mg+, Ba+, Sr+) nitrate with varying compositions along with splinters were used. But there were perceptible changes in the modus operandi of the terrorists. There had been a spurt in the use of different types of ammonium nitrate (AN) based explosives like AN, AN+Al, ANFO (ammonium nitrate and fuel oil/ diesel/kerosene), AN+wax, AN based gel/emulsion/slurry explosives with other ingredients. Urea nitrate was also obtained. The article contains a brief ...

The detection of hidden explosives has become an issue of utmost importance in recent years. While terrorism is not new to the international community, recent terrorist attacks have raised the issue of detection of explosives and have generated a great demand for rapid, sensitive and reliable methods for detecting hidden explosives. Counterterrorist Detection Techniques of Explosives covers recent advances in this area of research including vapor and trace detection techniques (chemiluminescence, mass spectrometry, ion mobility spectrometry, electrochemical methods and micromechanical sensors, such as microcantilevers) and bulk detection techniques (neutron techniques, nuclear quadrupole resonance, x-ray diffraction imaging, millimeter-wave imaging, terahertz imaging and laser techniques). This book will be of interest to any scientists involved in the design and application of security screening technologies including new sensors and detecting devices which will prevent the smuggling of bombs and explosives. * Covers latest advances in vapor and trace detection techniques and bulk detection techniques * Reviews both current techniques and those in advanced stages of development * Techniques that are described in detail, including its principles of operation, as well as its applications in the detection of explosives.

Detection and quantification of trace chemicals is a major thrust of analytical chemistry. In recent years much effort has been spent developing detection systems for priority pollutants. Less mature are the detections of substances of interest to law enforcement and security personnel:in particular explosives. This volume will discuss the detection of these, not only setting out the theoretical fundamentals, but also emphasizing the remarkable developments in the last decade. Terrorist events-airplanes blown out of the sky (PanAm 103 over Lockerbie) and attacks on U.S. and European cities (

The detection of hidden explosives has become an issue of utmost importance in recent years. While terrorism is not new to the international community, recent terrorist attacks have raised the issue of detection of explosives and have generated a great demand for rapid, sensitive and reliable methods for detecting hidden explosives. Counterterrorist Detection Techniques of Explosives covers recent advances in this area of research including vapor and trace detection techniques (chemiluminescence, mass spectrometry, ion mobility spectrometry, electrochemical methods and micromechanical sensors, such as microcantilevers) and bulk detection techniques (neutron techniques, nuclear quadrupole resonance, x-ray diffraction imaging, millimeter-wave imaging, terahertz imaging and laser techniques). This book will be of interest to any scientists involved in the design and application of security screening technologies including new sensors and detecting devices which will prevent the smuggling of bombs and explosives. * Covers latest advances in vapor and trace detection techniques and bulk detection techniques * Reviews both current techniques and those in advanced stages of development * Techniques that are described in detail, including its principles of operation, as well as its applications in the detection of explosives.

Testimony issued by the Government Accountability Office with an abstract that begins "Mandated to screen all checked baggage using explosive detection systems at airports by December 31, 2003, the Transportation Security Administration (TSA) deployed two types of screening equipment: explosives detection systems (EDS), which use computer-aided tomography X-rays to recognize the characteristics of explosives, and explosives trace detection (ETD) systems, which use chemical analysis to detect traces of explosive material vapors or residues. This testimony discusses (1) TSA's deployment of EDS and ETD systems and the impact of initially deploying these systems, (2) TSA and airport actions to install EDS machines in-line with baggage conveyor systems, and the federal resources made available for this purpose, and (3) actions taken by TSA to optimally deploy checked baggage screening systems."

Funding: The authors acknowledge funding from the EPSRC DTG (EP/L505079/1) and EPSRC (EP/N509759/1). ; Swabs taken from the surface of a suspicious object are a standard method of identifying a concealed explosive device in security-conscious locations like airports. In this paper we demonstrate a sensitive method to collect and detect trace explosive residues from improvised explosive devices using swabs and an optical sensor element. Swabs coated with a commercial fluoropolymer are used to collect material and are subsequently heated to thermally desorb the explosives, causing the quenching of light emission from a thin film luminescent sensor. We report the sorption and desorption characteristics of swabs loaded with 2,4-DNT tested with Super Yellow fluorescence sensors in a laboratory setting, with detection that is up to three orders of magnitude more sensitive than standard colorimetric tests. The method was then applied in field tests with raw military-grade explosives TNT, PETN and RDX, on various objects containing the explosives, and post-blast craters. We show for the first time results using organic semiconductors to detect sub-milligram amounts of explosive sorbed onto a substrate from real explosives in the field, giving a promising new approach for IED detection. ; Publisher PDF ; Peer reviewed

Surface-enhanced Raman spectroscopy (SERS) measurements of some common military explosives were performed with a table-top micro-Raman system integrated with a Serstech R785 miniaturized device, comprising a spectrometer and detector for near-infrared (NIR) laser excitation (785 nm). R785 was tested as the main component of a miniaturized SERS detector, designed for in situ and stand-alone sensing of molecules released at low concentrations, as could happen in the case of traces of explosives found in an illegal bomb factory, where solid microparticles of explosives could be released in the air and then collected on the sensor's surface, if placed near the factory, as a consequence of bomb preparation. SERS spectra were obtained, exciting samples in picogram quantities on specific substrates, starting from standard commercial solutions. The main vibrational features of each substance were clearly identified also in low quantities. The amount of the sampled substance was determined through the analysis of scanning electron microscope images, while the spectral resolution and the detector sensitivity were sufficiently high to clearly distinguish spectra belonging to different samples with an exposure time of 10 s. A principal component analysis procedure was applied to the experimental data to understand which are the main factors affecting spectra variation across different samples. The score plots for the first three principal components show that the examined explosive materials can be clearly classified on the basis of their SERS spectra.

Aviation safety and security has become a topic of paramount national concern. Informed decision making requires an appreciation of trends in technology in response to projected future terrorist activities. In the area of security, explosive detection is made possible by a bewildering array of newly offered equipment. This document describes the science and engineering of the various technologies. The information presented here was written for airline security, but it applies also to a wide range of military problems. -- Report documentation page. ; ONR# N001400WR20307. ; Approved for public release; distribution is unlimited.

DNT (2,4-dinitrotoluene), a volatile impurity in military-grade 2,4,6-trinitrotoluene (TNT)-based explosives, is a potential tracer for the detection of buried landmines and other explosive devices. We have previously described an Escherichia coli bioreporter strain engineered to detect traces of DNT and have demonstrated that the yqjF gene promoter, the sensing element of this bioreporter, is induced not by DNT but by at least one of its transformation products. In the present study, we have characterized the initial stages of DNT biotransformation in E. coli, have identified the key metabolic products in this reductive pathway, and demonstrate that the main DNT metabolite that induces yqjF is 2,4,5-trihydroxytoluene. We further show that E. coli cannot utilize DNT as a sole carbon or nitrogen source and propose that this compound is metabolized in order to neutralize its toxicity to the cells.