Method optimization for quantitative analysis of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) by liquid chromatography-electrospray ionization mass spectrometry

A simple, sensitive LC-ESI-MS method was optimized for quantitative analysis of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) in environmental samples. Under negative ionization mode, HMX can form adduct ions with various organic acids and salts, including acetic acid, formic acid, propionic acid, ammonium nitrate, ammonium chloride, sodium nitrite, and sodium nitrate. Acetic acid was chosen as additive and the ion, [M + CH₃COO]⁻ with m/z = 355 was used for selective ion monitoring (SIM) in this study. Good sensitivity was achieved with low acetic acid concentration in the mobile phase and relatively low capillary temperature. The method detection limit was 0.78 pg for HMX in standard solution. Linearity (R² > 0.9998) was obtained at low concentrations (0.5-50 μg/L). This method has been used to determine HMX concentrations in water samples and lizard egg samples from an animal exposure study.     

Construction and Evaluation of a Fluorescent Sensor for the Detection of High Explosives

A sensor for the detection of airborne nitrate explosives was developed and laboratory tested. The device consisted of a quartz optical fiber, of which a 4-cm length was stripped and treated with an aminoalkylmethoxysilane. A fluorescent surface was produced by chemically attaching a sulfonated polyaromatic fluorophore to the amino group of the silylated quartz. Excitation was effected by radiation admitted through the fiber. When explosive laden air was drawn across the fluorescent surface, the analyte molecules interacted with the fluorophore and caused the emission to be quenched. This signal was monitored as an indicator of the explosive and was shown to be effective for TNT, di- and mononitrotoluenes, Tetryl, RDX, and HMX (marginal). Sensitivities were in the ng/m³range, and the surface could be flushed and restored after a quenching episode. Few interferences were encountered among common substances brought in contact with the surface.     

雷酸家族史话

This article describes an introduction of fulminic acid. The story of fulminic acid and fulminates was introduced from the discovery of mercury fulminate to the concept of isomers and the success of Alfred Nobel in the development of explosives. This process provides a good example of integrating science and technology.     

Selection of phage displayed peptides for the detection of 2,4,6-trinitrotoluene in seawater

We have selected for phage displayed peptides that showed specific binding to a 2,4,6-trinitrotoluene (TNT) derivative, 2,4,6-trinitrobenzene (TNB) in environmentally relevant conditions, and have integrated the selected phage into a continuous flow immunosensor platform for the detection of TNT. A library of 12 random amino acid peptides (12-mers) displayed on phage was panned against TNB coupled to the protein bovine serum albumin (BSA) in a solution of artificial seawater. Eight phage clones, seven of which share an identical amino acid sequence, bound selectively to TNB-BSA in artificial seawater as judged by enzyme-linked immunosorbent assay (ELISA). Addition of TNT, inhibited binding of the phage. Whole phage were labeled with the dye cyanine 5 (Cy5), and incorporated into a flow sensor platform. Labeled phage were loaded onto a TNB-affi-gel packed column, and a reproducible signal, at least five times greater than background, was observed on repeat injections of 10 mg/l TNT dissolved in seawater. This study presents one of the first examples of phage selection in a non-physiological medium, and the first demonstration that dye-labeled phage can be integrated into a continuous flow sensor.     

Kinetic modeling study of the laser-induced plasma plume of cyclotrimethylenetrinitramine (RDX)

A kinetic model of a laser-induced breakdown spectroscopy (LIBS) plume of cyclotrimethylenetrinitramine (RDX) was developed for the analysis of processes responsible for the LIBS signature of explosives. Air and argon were considered as buffer gases. The model includes a set of processes involving ion chemistry, as well as excitation, ionization, and other processes affecting neutral and ion species. Modeling results show that the overall reaction process can be considered a two-stage process. The first stage corresponds to a fast approach to a quasi-stationary state, while the second stage corresponds to the change of quasi-stationary species concentrations due to the change in temperature. As a result of the two-stage process, the initial mechanism of explosive decomposition is not important in determining its signature in the LIBS measurement time window (1–30 μs). The main processes responsible for generation of excited states for the LIBS emission are electron-excitation impact processes. A mechanism for the appearance of a double peak of the C₂ species concentration in the RDX plasma plume was suggested. Double-peak behavior of the C₂ species was previously experimentally observed during laser ablation of graphite.     

Extraction and determination of trace amounts of energetic compounds in blood by gas chromatography with electron capture detection (GC/ECD)

This paper describes an efficient and sensitive method for determining five energetic compounds at trace levels (ng/mL) in blood by gas chromatography with electron capture detection (GC/ECD). For seven test concentrations (1-1250 ng/mL), the average recoveries (%) were 104 ± 16, 108 ± 22, 105 ± 14, 100 ± 22 and 108 ± 16 for hexahydro-1,3,5-trinitroso-1,3,5-triazine (TNX), hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine (DNX), hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine (MNX), hexahydro-1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and 2,4,6-trinitrotoluene (TNT) (n = 84), respectively. Analysis of DNX and RDX produced lower precision than other energetic compounds. Acetonitrile extracts of blood samples should be analyzed immediately as the test compounds can transform into unknown compounds, which lowered the recovery by 0-45% within 10 days at room temperature (∼20 °C). Maintaining sample extracts at 4 °C decreased loss of test compounds. The method described herein was validated by different analysis teams on different days. Two-way ANOVA indicated that there was no significant difference between analysis teams or days of analysis. The method was successfully employed in the analysis of blood samples from a mouse dosing study involving TNX and RDX.     

A theoretical study of explosive sensitizers

Quantum chemical calculations at the HF/6-31G^* and B3LYP/6-31G^* levels have been performed on five explosive sensitizers, ethyl nitrate (EN), n-propyl nitrate (NPN), isopropyl nitrate (IPN), 2-ethylhexyl nitrate (EHN) and tetraethylene glycol dinitrate (TEGDN). Theoretical study has made a detailed molecular-level investigation of the title compounds. Based on the Mulliken populations and bond lengths, the fission of the O₂–N₃ can be acceptable reasonably. Charge distribution analysis indicates that the five nitrates produce NO₂ gas during the dissociation of the O₂–N₃ weak bond. We also order the relative thermal stability of five nitrates on the basis of frontier orbital energy (E _HOMO, E _LUMO) and energy gap (ΔE = E _HOMO − E _LUMO).     

[Mn(CHZ)3](ClO4)2的制备、晶体结构和应用研究

碳酰肼[1]分子中有5个含孤电子对原子, 因此可作为单齿或多齿配体与多种金属离子配位[2～3]; 而且, 碳酰肼是肼的衍生物, 具有强还原性, 可用作含能材料的组分, 所以, 其配合物在含能材料领域引起了极大的关注[3～9]. 通过高氯酸锰水溶液和碳酰肼水溶液直接化合的方法得到了标题化合物的单晶, 测定了其晶体结构, 并研究了其爆炸性能.     

Radiation-based security

The problems presented in different security areas are varied but the solutions that have been offered are generally based upon the same principles. Employing radiation to locate and identify explosives or contraband has been most obvious at airports but other locations are now receiving equal attention. Neutron and X-ray interrogation are the systems most frequently employed. However, the more recently developed approaches such as multi-view dual-energy imaging and the use of high-speed diffraction measurements are the most likely systems to become widely available. This review looks briefly at the neutron and X-ray based systems that have been developed indicating their mode of operation and their advantages and disadvantages. It then summarizes the current state-of-the-art. The paper finishes by looking in some detail at one of the most promising areas of development—in-line diffraction measurements.     

基于爆炸火光光谱分析的大当量爆炸场破片速度测试方法研究

为了解决战斗部爆炸过程中,因爆炸物当量较大造成爆燃火球持续时间长,覆盖面积大,近场位置破片速度参数难于获取的问题,提出一种以激光光幕为有效传感区域的光电收发一体的测试方法。通过分析三种不同类型战斗部爆炸火光特征光谱分布可知,在0.3~1.0 μm波段内火光相对光强度较低。以此为依据,采用定距测时原理和原向反射技术,由固体激光器、菲涅尔透镜、窄带滤光器、高速光电传感器等关键光学元件构建破片速度参数获取的光学系统。系统光路收发一体,结构紧凑,窄带滤光片与激光光源配合使用避开火光光谱,有效抑制背景光的干扰。采用该系统进行了不同型号、当量的战斗部静爆破片速度参数测试现场实验,通过美国NI数据采集系统记录数据并对信号进行去噪和识别,成功获取了较高信噪比的波形信号。实验结果表明：本方案可完成爆心10~15 m附近破片速度的准确测试,最小可测破片尺寸为4 mm,获取破片速度可达1 200 m·s-1,与靶板测试结果对比可知捕获率优于95%。由于采用菲涅尔透镜形成矩形光幕,光幕上下的光强分布一致,水平方向光强均匀度达到80%以上,因此系统还可初步区分预制破片速度与尺寸的对应关系。