Chemical attribution of the homemade explosive ETN - Part II: Isotope ratio mass spectrometry analysis of ETN and its precursors

Analysis and detection of homemade explosive TACP

This paper focuses on tetraamminecopper(II) perchlorate (TACP), a relatively newly used and popular homemade explosive that is insufficiently described in the literature. The compound was analyzed using commonly used forensic laboratory techniques such as FTIR, Raman, XRPD, and DTA. The TACP molecule was labeled with four 15N atoms on ammonia ligands to assign vibrational modes to the resulting bands. The paper also describes the thermal decomposition of TACP using thermoanalytical methods TGA/MS. The TACP decomposes to the final product CuO in six distinct ranges, releasing N2O, NO, HCl, O2, H2O, and NH3. It has been found that TACP is not a stable compound and will decompose spontaneously to ammonia, ammonium perchlorate, and basic copper perchlorate within a few months if exposed to air at room temperature. Residues of precursors have been detected in TACP prepared by four improvised preparation methods published on the Internet. These residues can be used to identify the precursor used in the preparation. The post-blast residues of TACP are of ordinary shape, but the use of TACP as an explosive can be indicated by the presence of a high content of copper and chlorine atoms in post-blast residues. The results of canine detection of TACP indicate that the dog is able to detect TACP, but the dog is likely to focus on the smell of ammonia in the TACP odor.

75 years of forensic profiling: A critical review

The interest in characterization of drugs abused started in 1948 with the aim of determining the origin of opium. After 75 years there is still a great interest in this approach, called geo-profiling, chemical or forensic profiling in the following decades. Recently chemical attribution signatures (CAS) were proposed by the authors who studied "synthesis precursors and byproducts, impurities, degradation products, and metabolites in various biological matrices" of fentanyl. Forensic profiling evolved during these decades: new analytical approaches were tested and it was applied to more and more products, which threaten the health and security of citizens worldwide. In substances of natural origins (e.g. opium, cannabis and cocaine), it is possible to exploit the great variability of both elements and organic chemical compounds and to study chemical compounds such as reagents and solvents, by-products, and cutting agents used in the production chain. Profiles can be used to classify products from different seizures into groups of similar samples (tactical intelligence) or to determine the origin of samples (strategic intelligence). Chromatographic approaches coupled to mass spectrometry are very common to determine organic profiles, while elemental profiles are obtained by nuclear activation analysis, inductively coupled plasma mass spectrometry or ion beam analysis. A very important role in the field is played by isotope ratio analysis. Approaches to obtain forensic profiles are available also for chemical warfare agents, explosives, illegal medicines, doping agents, supplements, food. Chemometrics can be particularly useful to establish the authenticity of products and for the interpretation of large amount of forensic data. The future of forensic profiling is a challenge for forensic sciences. Organized crime is involved in the manufacturing of a large number of illegal products and forensic profiling is a very powerful tool to support the health of citizens and the administration of justice worldwide.

Properties of Erythritol Tetranitrate from Molecular Dynamics Simulation

The nonpolarizable force field for alkyl nitrates developed by Borodin et al. [J. Phys. Chem. B, 2008, 112, 734-742] has been employed to calculate selected properties of crystalline and liquid erythritol tetranitrate (ETN). The set of partial charges proposed by Borodin for pentaerythritol tetranitrate (PETN) was used except for a small correction to the H atom charges to ensure charge neutrality owing to the absence of the neopentyl carbon in ETN. The force field was used to compute the isothermal compression curve, lattice parameters, heat capacity, thermal expansivity, single crystal elastic constants, and Gruneisen parameters of crystalline ETN. The density- and temperature-dependent viscosities of liquid ETN are also reported. We anticipate that these data will be of some utility to the development of equations of state and thermomechanical models for ETN.

[Recent advances in stable isotope ratio analysis of common explosives]

炸药的深度比对与溯源对于爆炸案事件的侦破具有重大意义,以不同地域来源的原料或不同生产工艺生产的炸药,其组成元素的稳定同位素比值具有差异,因而稳定同位素比值可作为炸药深度比对与溯源的重要指标。稳定同位素比值质谱法(IRMS)作为一种高精度的稳定同位素比值测量手段,已逐渐发展成熟,与元素分析仪、气相色谱仪、液相色谱仪等仪器联用,在食品安全、环境保护、法庭科学等领域应用广泛。IRMS在炸药比对与溯源上亦发挥了重要作用,自1975年IRMS被应用于区分不同国家生产的三硝基甲苯(TNT)以来,IRMS已成功用于多种炸药的分析。但目前尚未见有文献系统地总结常见炸药的稳定同位素比值分析研究进展。该文介绍了稳定同位素比值分析的相关原理、仪器组成及特点,分别总结了硝酸铵、黑火药、TNT、太恩、黑索金等常见炸药的稳定同位素比值分析方法,汇总了文献报道的不同国家生产的硝酸铵、黑火药、TNT等炸药的稳定同位素比值。文章就不同炸药的稳定同位素比值差异、炸药生产、存储过程中相关因素对同位素比值的影响,爆炸前后稳定同位素比值的变化情况等内容进行了分析。本文还指出了目前炸药的稳定同位素比值分析研究中存在的问题,对可能的解决办法进行了讨论,对未来的发展方向提出了建议。