Fluorescent sensors for the detection of chemical warfare agents

Along with biological and nuclear threats, chemical warfare agents are some of the most feared weapons of mass destruction. Compared to nuclear weapons they are relatively easy to access and deploy, which makes them in some aspects a greater threat to national and global security. A particularly hazardous class of chemical warfare agents are the nerve agents. Their rapid and severe effects on human health originate in their ability to block the function of acetylcholinesterase, an enzyme that is vital to the central nervous system. This article outlines recent activities regarding the development of molecular sensors that can visualize the presence of nerve agents (and related pesticides) through changes of their fluorescence properties. Three different sensing principles are discussed: enzyme-based sensors, chemically reactive sensors, and supramolecular sensors. Typical examples are presented for each class and different fluorescent sensors for the detection of chemical warfare agents are summarized and compared.     

化学恐怖威胁源特征研究

化学武器的使用形态最早可以追溯到公元前431年斯巴达人向雅典人投射的沥青和硫磺混合抛射物.两次世界大战期间,氯气、芥子气等攻击手段在战场上被大规模使用.1995年东京地铁沙林事件发生后,化学武器作为一种非常规的恐怖袭击形式引发广泛关注.化学恐怖威胁源是关乎化学恐怖袭击的元要素,把握其特征对于防范、处置化学恐怖事件及建设...     

Innovation in Crop Protection: Trends in Research

In the absence of the remarkable levels of growth in the yields of important crops, neither the rapid increase in living standards in industrialized countries nor the adequate standard of nutrition for the greater part of the world's population would have been possible. Alongside high-yielding varieties, improved agricultural techniques, and rapid mechanization, the chemical industry has also contributed substantially to progress in agriculture since roughly the middle of the nineteenth century. From the chemists "kitchens" came two "magic weapons": artificial fertilisers and chemical agents for crop protection. Today both have become indispensable to modern yield- and quality-orientated agriculture. This review spans the development of the crop-protection industry from its earliest beginnings to the present day and attempts to portray how the research-based crop-protection industry is prepared for current and future challenges. Considerable space is thus dedicated to the discussion of trends in research.     

Identification and quantitative determination of diphenylarsenic compounds in abandoned toxic smoke canisters

Knowledge of the exact nature of the constituents of abandoned chemical weapons (ACW) is a prerequisite for their orderly destruction. Here we report the development of analytical procedures to identify diphenylchloroarsine (DA/Clark I), diphenylcyanoarsine (DC/Clark II) and related substances employed in one of the munitions known as "Red canister". Both DA and DC are relatively unstable under conventional analytical procedures without thiol derivatization. Unfortunately however, thiol drivatization affords the same volatile organo-arsenic derivative from several different diphenylarsenic compounds, making it impossible to identify and quantify the original compounds. Further, diminishing the analytical interference caused by the celluloid powder used as a stacking material in the weapons, is also essential for accurate analysis. In this study, extraction and instrumental conditions have been evaluated and an optimal protocol was determined. The analysis of Red canister samples following this protocol showed that most of the DA and DC associated with pumice had degraded to bis(diphenylarsine)oxide (BDPAO), while those associated with celluloid were dominantly degraded to diphenylarsinic acid (DPAA).     

Utilisation of separation methods in the analysis of chemical warfare agents

Chemical warfare agents and their degradation products represent a broad group of compounds with different chemical properties (polarity, volatility, thermostability, etc.). These chemicals often have to be detected and determined in complex matrices and therefore highly efficient separation techniques hyphenated to selective and sensitive detectors play an indispensable role. This review offers an overview of selected papers devoted to the title subject. It cannot be considered as a comprehensive literature compilation but should allow the reader to obtain an insight into the application of separation techniques in the important area of human protection and control of chemical weapons.     

Chemical Ionization Methods in Selective Chromatography–Mass Spectrometry of Alkylphosphonic Acid Derivatives

Control over the destruction of chemical weapons requires analyses of various complex samples like water, soils, paint coats, mechanical rubber articles, vegetation, etc. aimed at the detection and determination of toxic substances related to chemical weapons. This paper considers the developed procedures of chromatographic–mass spectrometric analysis with positive- and negative-ion chemical ionization. These procedures eliminate false positive and negative results in determining complex samples containing trace organophosphorus compounds.     

Monitoring Chemical Warfare Agents: A New Method for the Detection of Methylphosphonic Acid

Methylphosphonic acid (MPA) is the degradation product of many chemical warfare agents. The convenient detection of this substance would aid in field testing to confirm illicit manufacture and use of banned chemical weapons. Efficient functionalization of MPA with an aromatic diazo compound allowed binding by monoclonal antibodies elicited by using an analogous hapten (see scheme). An ELISA assay was rapid, sensitive, and specific.     

Chemical network algorithms for the risk assessment and management of chemical threats

A network of chemical threats: Current regulatory protocols are insufficient to monitor and block many short-route syntheses of chemical weapons, including those that start from household products. Network searches combined with game-theory algorithms provide an effective means of identifying and eliminating chemical threats. (Picture: an algorithm-detected pathway that yields sarin (bright red node) in three steps from unregulated substances.).     

A new incorporation mechanism for trivalent actinides into bioapatite: a TRLFS and EXAFS study

One of the most toxic byproducts of nuclear power and weapons production is the transuranics, which have a high radiotoxicity and long biological half-life due to their tendency to accumulate in the skeletal system. This accumulation is inhomogeneous and has been associated with the chemical properties and structure of the bone material rather than its location or function. This suggests a chemical driving force to incorporation and requires an atomic scale mechanistic understanding of the incorporation process. Here we propose a new incorporation mechanism for trivalent actinides and lanthanides into synthetic and biologically produced hydroxyapatite. Time-resolved laser fluorescence spectroscopy and extended X-ray absorption fine structure have been used to demonstrate that trivalent actinides and lanthanides incorporate into the amorphous grain boundaries of apatite. This incorporation site can be used to explain patterns in uptake and distribution of radionuclides in the mammalian skeletal system.     

Chemisches bei Caesar. De bello Gallico...

In his “Gallic War”, Caesar alredy mentioned several materials, the production of which required a certain chemical knowledge, for example iron needed for weapons, woad for body painting, or wine. In this article the knowledge in manufacturing these and some other products at the time of the ancient Romans is described, with special regard to Pliny the Elder's Historia naturalis. It becomes evident that it is worth looking at the works of ancient authors from a chemical‐historical point of view.     

Globale und regionale Klimapolitik

Climate change is a global challenge. So far, global agreements fail to limit the temperature rise to 2°C or 1,5°C. With its products as well as its innovative production processes, the chemical industry makes a decisive contribution to climate protection. Appropriate regional and global policy frameworks are indispensable in order for the chemical industry to fully exploit its innovation potential. EU regional measures should not be an additional burden to the most efficient producers compared to their global competitors.     

A New Approach to the Asymmetric Synthesis of 3-Methylpyrrolidine Alkaloids

3-Methylpyrrolidine alkaloids 1-5,isolated from the poison gland of several species of ants Leptothoracini (Myrmicinae), have been found to be pheromones and chemical weapons of them^[1,2].Since these alkaloids are only available at nanogram scale, the development of asymmetric synthesis is of importance, in particular for evaluating their bioactivities.     

Technological advancements for the detection of and protection against biological and chemical warfare agents

There is a growing need for technological advancements to combat agents of chemical and biological warfare, particularly in the context of the deliberate use of a chemical and/or biological warfare agent by a terrorist organization. In this tutorial review, we describe methods that have been developed both for the specific detection of biological and chemical warfare agents in a field setting, as well as potential therapeutic approaches for treating exposure to these toxic species. In particular, nerve agents are described as a typical chemical warfare agent, and the two potent biothreat agents, anthrax and botulinum neurotoxin, are used as illustrative examples of potent weapons for which countermeasures are urgently needed.     

Biology evolves to fight chemistry

A human enzyme variant, PON1-G3C9, accidentally catalyzes the hydrolysis of organophosphorus chemical weapons. In this issue of Chemistry & Biology, Goldsmith and coworkers describe a new PON1 variant with improved hydrolysis by several hundred fold; enough that it may protect animals from a toxic dose.     

Design and synthesis of an alpha,alpha-difluorophosphinate hapten for antibody-catalyzed hydrolysis of organophosphorus nerve agents

In a new approach to the safe neutralization of organophosphorus chemical weapons, we designed a hapten to elicit catalytic antibodies with phosphatase activity. Here we report the synthesis of this alpha,alpha-difluorophosphinate hapten 6. Various methods for the introduction of the key alpha,alpha-difluoromethyl feature into the phosphinate hapten are discussed. The best results were obtained with the electrophilic gem-difluorinating agent N-fluorobenzenesulfonimide.     

Biosensors in forensic analysis. A review

Forensic analysis is an important branch of modern Analytical Chemistry with many legal and socially relevant implications. Biosensors can play an important role as efficient tools in this field considering their well known advantages of sensitivity, selectivity, easy functioning, affordability and capability of miniaturization and automation. This article reviews the latest advances in the use of biosensors for forensic analysis. The different methodologies for the transduction of the produced biological events are considered and the applications to forensic toxicological analysis, classified by the nature of the target analytes, as well as those related with chemical and biological weapons critically commented. The article provides several Tables where the more relevant analytical characteristics of the selected reported methods are gathered.     

Md-simulation of α-keratin intermediate filaments

In recent years powerful computer systems have become readily accessible to simulate complex chemical problems. Based on the primary structure of the intermediate filament monomer unit of wool, small sequences are selected. Their molecular dynamic behaviour is simulated, in order to investigate the secondary and tertiary structure as well as their stability. The simulations are carried out for a helical segment and a linker segment, selecting the ideal α-helix as start conformation. In vacuum all simulations show an unstable α-helix due to shifts of the intrahelical hydrogen bonds. So a new helical structure with a larger helix diameter is formed. However in simulations with surrounding water the α-helix remains stable throughout the simulation time. Up to now it has not been possible to dectect any fundamental difference in the molecular dynamic behaviour of the helical and the linker segment.     

Supramolecular Sensing of a Chemical Warfare Agents Simulant by Functionalized Carbon Nanoparticles

Real-time sensing of chemical warfare agents by optical sensors is today a crucial target to prevent terroristic attacks by chemical weapons. Here the synthesis, characterization and detection properties of a new sensor, based on covalently functionalized carbon nanoparticles, are reported. This nanosensor exploits noncovalent interactions, in particular hydrogen bonds, to detect DMMP, a simulant of nerve agents. The nanostructure of the sensor combined with the supramolecular sensing approach leads to high binding constant affinity, high selectivity and the possibility to reuse the sensor.     

Recent developments in methods of chemical analysis in investigations of firearm-related events

A review of recent (approximately the last ten years) developments in the methods used for chemical analysis in investigations of firearm-related events is provided. This review discusses:examination of gunshot (primer) residues (GSR) and gunpowder (propellant) residues on suspects and their clothing;detection of firearm imprints on the hands of suspects;identification of the bullet entry holes and estimation of shooting distance;linking weapons and/or fired ammunition to the gunshot entries, and estimation of the time since discharge.     

Depleted uranium: possible health effects and experimental issues

In 2000, cases of cancer have been reported among Italian troops involved in the peace-keeping missions in Bosnia and Kosovo, and a Committee of Enquiry was set-up to study all these cases of tumour pathology and to verify the existence of a correlation, if any, with depleted uranium (DU) weapons used in the area. This paper reviews the results of epidemiological finding, indicating that the only type of cancer for which a statistically significant excess was observed was Hodgkin's lymphoma (HL). Referring to these data, a critical review of the current knowledge and postulates on uranium exposure is also presented to clarify why, up to this time, several problems have prevented from ascertaining whether or not lymphatic cancers are correlated with DU exposure. Moreover, the paper analyses and discusses up-to-date monitoring results in the contaminated countries and reviews advanced techniques to detect DU in biological and environmental samples, including gamma spectroscopy, a relatively manageable technique.