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Chromatography and mass spectrometry of chemical warfare agents, toxins and related compounds: state of the art and future prospects
Abstract
Methods for the identification of chemical warfare agents, toxins, bioregulators and related products are frequently reported in literature. These methods are often based on instrumental analysis using chromatography (gas and liquid) and mass spectrometry. Here, these instrumental techniques are discussed in several applications, new developments and trends based on a review of the literature published since 1990. Apart from new instrumental developments, it is shown that modern analytical chemistry can be successfully applied to perform identification in the broad field of analytes ranging from chemical to biological warfare agents.
... Referring to Ying et al. (2007), analyzing nerve agents in environmental and biological samples is usually carried out using analytical techniques that have a very high sensitivity, reliability and precision [51], such as gas chromatography (GC) [52,53], liquid chromatography (LC) [52,54], gas chromatography mass spectrometry (GCMS) [52,55,56], ion chromatography (IC) [57], atomic emission detection (AED) [58], capillary electrophoresis (CE) [54,59], CE coupled with flame photometry [54], CE with conductivity detection [60]. In spite of these advantages, the techniques require expensive instrumentation and highly trained personnel, as well as being time consuming and incompatible with field analysis. ...
... Referring to Ying et al. (2007), analyzing nerve agents in environmental and biological samples is usually carried out using analytical techniques that have a very high sensitivity, reliability and precision [51], such as gas chromatography (GC) [52,53], liquid chromatography (LC) [52,54], gas chromatography mass spectrometry (GCMS) [52,55,56], ion chromatography (IC) [57], atomic emission detection (AED) [58], capillary electrophoresis (CE) [54,59], CE coupled with flame photometry [54], CE with conductivity detection [60]. In spite of these advantages, the techniques require expensive instrumentation and highly trained personnel, as well as being time consuming and incompatible with field analysis. ...
... Referring to Ying et al. (2007), analyzing nerve agents in environmental and biological samples is usually carried out using analytical techniques that have a very high sensitivity, reliability and precision [51], such as gas chromatography (GC) [52,53], liquid chromatography (LC) [52,54], gas chromatography mass spectrometry (GCMS) [52,55,56], ion chromatography (IC) [57], atomic emission detection (AED) [58], capillary electrophoresis (CE) [54,59], CE coupled with flame photometry [54], CE with conductivity detection [60]. In spite of these advantages, the techniques require expensive instrumentation and highly trained personnel, as well as being time consuming and incompatible with field analysis. ...
A number of recent terrorist attacks make it clear that rapid response, high sensitivity and stability are essential in the development of chemical sensors for the detection of chemical warfare agents. Nerve agent sarin [2-(fluoro-methyl-phosphoryl) oxypropane] is an organophosphate (OP) compound that is recognized as one of the most toxic chemical warfare agents. Considering sarin’s high toxicity, being odorless and colorless, dimethyl methylphosphonate (DMMP) is widely used as its simulant in the laboratory because of its similar chemical structure and much lower toxicity. Thus, this review serves to introduce the development of a variety of fabricated chemical sensors as potential sensing materials for the detection of DMMP in recent years. Furthermore, the research and application of carbon anotubes in DMMP polymer sensors, their sensitivity and limitation are highlighted. For sorption-based sensors, active materials play crucial roles in improving the integral performances of sensors. The novel active materials providing hydrogen-bonds between the polymers and carbon nanotubes are the main focus in this review.
... Les agents neurotoxiques sont des composés stables thermiquement qui présentent une volatilité élevée à température ambiante. De ce fait, ils peuvent être analysés par chromatographie en phase gazeuse (GC) [26][27][28] . C'est une méthode qui permet de séparer divers composés sur une colonne adaptée afin de les identifier suivant leur temps de rétention. ...
... A titre d'exemple, la spectroscopie d'absorption IR 26,31 ou la spectrométrie de masse (MS) 32 sont le plus souvent employées. La GC-MS demeure la méthode de choix pour la détection des organophosphorés au laboratoire 2,29 car elle est caractérisée par une excellente sensibilité alliée à une bonne sélectivité sans équivoque, pour l'identification rapide des agents chimiques de guerre 27,33 . Plus de 60 agents chimiques contenant du Méthylphosphonate et du fluor ont été étudiés par l'équipe de Borret afin de mettre en évidence, sans ambigüité, les organophosphorés tels que le Soman ou le Sarin 34 . ...
... De plus, c'est un appareil onéreux et très complexe qui nécessite une main d'oeuvre qualifiée. 27 ...
La détection d’agents organophosphorés (OPs) demeure l’un des problèmes majeurs à résoudre pour prévenir la menace chimique. A cet effet, la recherche de capteurs sensibles, sélectifs, portables reste d’un grand intérêt. Dans ce projet, notre intérêt s’est porté vers des microleviers dont le principe repose sur la modification de leur fréquence de résonance due à une adsorption de molécules à leur surface. Un concept associant la nanostructuration et la fonctionnalisation a été étudié pour améliorer les performances des leviers. Ainsi, la surface des microleviers a été nanostructurée par voie solvothermale avec des nanobâtonnets de TiO2 pour accroitre leur capacité d’adsorption et leur sensibilité. Ces leviers nanostructurés ont ensuite été fonctionnalisés par des molécules (alcool, oxime) susceptibles de se lier spécifiquement aux OPs pour améliorer leur sélectivité. La nanostructuration et la fonctionnalisation ont été préalablement optimisées sur des surfaces modèles avant d’être transférées sur des leviers. Une étude paramétrique a été menée pour évaluer l’impact des conditions de synthèse sur la morphologie des structures. La capacité de greffage des nanostructures a été évaluée et les meilleures structures ont été reproduites sur les leviers pour les tests de détection d’un simulant d’OPs. Des études plus spécifiques ont également été menées pour comprendre les mécanismes d’interactions entre les OPs et le TiO2.
... This reaction between BChE and neurotoxic CWC Schedule 1A not only highlights the importance of this enzyme as a biomarker, but also illustrates its potential use as a bioscavenger. Therefore, it can be a potential prophylactic measure by reacting in stoichiometric manner with nerve agents [168][169][170][171][172][173][174][175][176][177][178][179][180][181]. Scheme 5. Digestion and fluoride reactivation products from biological matrices. ...
... This reaction between BChE and neurotoxic CWC Schedule 1A not only highlights the importance of this enzyme as a biomarker, but also illustrates its potential use as a bioscavenger. Therefore, it can be a potential prophylactic measure by reacting in stoichiometric manner with nerve agents [168][169][170][171][172][173][174][175][176][177][178][179][180][181]. The knowledge on the reaction between nerve agents and cholinesterases may be useful to identify exposure to such toxic chemicals. ...
... This reaction between BChE and neurotoxic CWC Schedule 1A not only highlights the importance of this enzyme as a biomarker, but also illustrates its potential use as a bioscavenger. Therefore, it can be a potential prophylactic measure by reacting in stoichiometric manner with nerve agents [168][169][170][171][172][173][174][175][176][177][178][179][180][181]. ...
This article describes acetylcholinesterase (AChE), an enzyme involved in parasympathetic neurotransmission, its activity, and how its inhibition can be pharmacologically useful for treating dementia, caused by Alzheimer’s disease, or as a warfare method due to the action of nerve agents. The chemical concepts related to the irreversible inhibition of AChE, its reactivation, and aging are discussed, along with a relationship to the current international legislation on chemical weapons.
Open Access: https://doi.org/10.3390/biom10030414
... Furthermore, traditional analytical techniques for ammonia detection, such as gas chromatography [278][279][280], ion mobility spectroscopy [279], or mass spectrometry [280,281] are limited by their impracticality, slow response time, and large instrument size. ...
... Furthermore, traditional analytical techniques for ammonia detection, such as gas chromatography [278][279][280], ion mobility spectroscopy [279], or mass spectrometry [280,281] are limited by their impracticality, slow response time, and large instrument size. ...
Meat cultivation via cellular agriculture holds great promise as a method for future food production. In theory, it is an ideal way of meat production, humane to the animals and sustainable for the environment, while keeping the same taste and nutritional values as traditional meat and having additional benefits such as controlled fat content and absence of antibiotics and hormones used in the traditional meat industry. However, in practice, there is still a number of challenges, such as those associated with the upscale of cultured meat (CM). CM food safety monitoring is a necessary factor when envisioning both the regulatory compliance and consumer acceptance. To achieve this, a multidisciplinary approach is necessary. This includes extensive development of the sensitive and specific analytical devices i.e., sensors to enable reliable food safety monitoring throughout the whole future food supply chain. In addition, advanced monitoring options can help in the further optimization of the meat cultivation which may reduce the currently still high costs of production. This review presents an overview of the sensor monitoring options for the most relevant parameters of importance for meat cultivation. Examples of the various types of sensors that can potentially be used in CM production are provided and the options for their integration into bioreactors, as well as suggestions on further improvements and more advanced integration approaches. In favor of the multidisciplinary approach, we also include an overview of the bioreactor types, scaffolding options as well as imaging techniques relevant for CM research. Furthermore, we briefly present the current status of the CM research and related regulation, societal aspects and challenges to its upscaling and commercialization.
... Sulfur mustard (bis(2-chloroethyl) sulfide, HD), an organic sulfur compound known for its high toxicity and potential to cause severe damage to skin, [1] eyes, and the respiratory tract, is considered one of the earliest chemical warfare agents (CWAs) used in armed conflicts. [2][3][4][5] Therefore, it is imperative to rapidly convert HD into a non-toxic substance for defensive purposes. [6,7] Among the various degradation pathways for HD, [8] the selective oxidation of sulfides into sulfoxides has attracted extensive attention as it can ensure rapid detoxification and minimize the formation of harmful by-products associated with alternative pathways. ...
The development of novel catalysts for the rapid detoxification of sulfur mustard holds paramount importance in the field of military defense. In this work, titanium dioxide‐phosphomolybdic acid sub‐1 nm nanobelts (TiO2/PMA SNBs) are employed as effective catalysts for the ultra‐fast degradation of mustard gas simulants (2‐chloroethyl ethyl sulfide, CEES) with 100% selectivity and a half‐life (t1/2, time required for 50% conversion) as short as 12 s, which is the fastest time to the best of the knowledge. Even in dark conditions, this material can still achieve over 90% conversion within 5 min. A mechanism study reveals that the rapid generation rate of ¹O2 and O2•− in the presence of TiO2/PMA SNBs and H2O2 plays a crucial role in facilitating the efficient oxidation of CEES. A filter layer of a gas mask loaded with TiO2/PMA SNBs and H2O2/polyvinylpyrrolidone cross‐linked complex (PHP) is constructed, which demonstrates remarkable stability and exhibits exceptional efficacy in the detoxification of CEES in the presence of a small amount of water. This innovation offers great potential for enhancing personal protective equipment in practical applications.
... 신경작용제를 실제 전장에서 신속하게 탐지하기 위 하여 비색 검출법 [1] , 형광 분석법 [2] , 효소 분석법 [3] 및 가스크로마토그래프 질량분석 [4] 등 다양한 방법들이 지금까지 개발되어 왔다. 그러나 이러한 각 탐지 방법 에는 느린 응답, 낮은 감도, 운영 복잡성, 높은 전력, 높은 제작비용 및 탐지 식별성 부족과 같은 실제 전 장에 적용하기 어려운 제한점들이 존재하였고 [5][6][7] , 이 러한 제한점을 극복하고자 최근에는 표적 분석 물질 간의 직접적인 화학적 상호 작용에 의한 전기적 신호 변화를 감지하는 화학 저항 센서들이 연구되어 왔다 [8][9][10][11] . ...
In continuous research of detecting highly toxic chemical warfare agents to ensure preparedness for the future battlefield, flexible and wearable sensor platforms with high sensitivity are still demanding. Herein we demonstrate a facile fabrication of polypyrrole-based chemiresistors on cellulose paper for the detection of nerve gas simulants. In order to optimize electrical properties of sensor platform, conducting polymer made of polypyrrole were first synthesized on flexible cellulose paper and interdigitated electrodes were formed thereon. Following confirmation of polypyrrole and/or oxime moiety through FT-IR analyses, electrical characteristics were measured in the various ratio of monomers between simple pyrrole and oxime-modified one. Typically for the optimized chemiresistor(2:8 molar ratio of simple pyrrole and oxime-modified one), eleven species of chemical warfare agents were examined and enhanced conductivity(104~105 order) was observed for three simulants(diethyl cyanophosphonate, diisopropyl fluorophosphonate and diethyl chlorophosphonate), which was mainly attributed to intermolecular hydrogen bonding, while no significant responses was recorded against sixteen common volatile organic chemicals.
... Various classical analytical methods have been used in the past to track ammonia gas levels. These include the detection of ammonia gas using ion mobility spectrometry, mass spectrometry, and chromatography methods like gas and liquid chromatography [7][8][9]. However, these methods have the disadvantage of using huge instrument setups for gas detection and responding very slowly. ...
Paper-based sensors have emerged as a viable and cost-effective alternative to complex and expensive sensing devices. This study developed a paper-based electronic sensor for detecting ammonia by in-situ synthesizing the emeraldine state of polyaniline (PANi) within a Whatman filter paper matrix. The in-situ polymerization of PANi within the paper matrix resulted in a uniform green-colored PANi coating on the paper surface. Scanning electron microscopy (SEM) studies showed well-distributed rod-shaped PANi molecules on the paper surface. The ammonia paper sensor revealed increased resistance with increasing concentrations of gaseous ammonia. Optimal stoichiometric concentrations of HCl and aniline were determined to achieve a paper sensor with rapid response and recovery times. The selectivity of the paper sensor for ammonia was tested against various volatile organic compounds and moisture, exhibiting a selective response specifically to ammonia among the tested chemicals.
... For several decades, gas chromatography-mass spectrometry (GC-MS) has been widely used to analyze chemical warfare agents (CWAs) (Kientz 1998;Black et al. 1994). GC is commonly utilized as a separation technique and is often combined with various ionization methods, such as flame, photo, and thermal desorption. ...
In the present study, we developed the detection method for gas-phase aromatics and other molecules ionizable by soft X-rays demonstrated using methyl salicylate which is one of the chemical warfare agent simulants by using soft X-ray and aerosol measurement techniques. The aromatic chemical compounds which have the benzene ring are well detected by the soft X-ray assisted detection method which converts gas vapors to nanoparticles through the photochemical processes. The present study reports on the formation of nanoparticles by describing the stage change during the soft X-ray irradiation: particle-free mode; nucleation mode; transition mode; accumulation mode; and stable mode. In a controlled environment, the empirical calibration curves can predict ppbv-level methyl salicylate vapor concentrations using particle number or volume concentration data obtained from the real-time aerosol detection instrument. We expect that this technology can be utilized for calibrating or intercomparing other instruments that measure methyl salicylate concentrations.
... There have been numerous efforts to develop an analytical method for lewisite, specifically L1, all with varying success (Hooijschuur, Kientz, and Brinkman 2002;Östin 2012). Previous techniques that analyze for L1 include gas chromatographymass spectrometry (GC-MS), inductively coupled plasma-mass spectrometry (ICP-MS), and liquid chromatographymass spectrometry (LC-MS) Hooijschuur, Kientz, and Brinkman 2002;Kientz 1998;U.S. EPA 2014;Witkiewicz, Mazurak, and Szulc 1990). ICP-MS uses arsenic (As) speciation to identify the presence of L1; however, if any other forms of As are present, such as naturally occurring metalloid in soils or Asladen pesticides, ICP-MS cannot differentiate and identify the metallic source. ...
The unexpected release of chemicals into the environment requires estimation of human health risks, followed by risk management decisions. When environmental concentrations of toxicants are associated with adverse health risks, the limit for analytical measurement needs to be at or below the risk threshold. The aim of this study was to assess chemical contaminants that have the potential to produce acute adverse human health impacts following oral consumption of contaminated drinking water. The U.S. Environmental Protection Agency's (EPA) Candidate Contaminant List, version 4 (CCL4) and EPA's Selected Analytical Methods (SAM) document were screened to identify 24 chemicals that exist as a solid or liquid at room temperature, with acute oral LD50 (lethal dose in 50% of the test population) values < 500 mg/kg-d and water solubility > 500 mg/L at ambient temperature. While these screening criteria were used to identify prioritized needs for targeted research, it does not imply that other chemicals on the CCL4 and SAM lists are not issues in acute and chronic exposures. Of these 24 most toxic and most soluble chemicals, this evaluation identified 6 chemicals (2-chlorovinylarsonous acid, lewisite, N-nitrosopyrrolidine, N-nitrosodiethylamine, 3-hydroxycarbofuran, and triethylamine) lacking either sufficient toxicity value information or analytical sensitivity required to detect at levels protective against adverse effects in adults for acute exposures. This assessment provides an approach for gap identification and highlights research needs related to water contamination incident involving these six priority chemicals.
... Thus, a rapid and reliable sarin detection system is very significant. Various methods such as mass spectroscopy [7], fluorescent sensors [8], photoluminescent sensors [9], and chromatography [10] have been introduced for nerve agent identification. However, they need expensive instruments, trained personnel, and elaborate sample preparation, so they cannot quickly be utilized for applied applications [11]. ...
The evaluation of sarin nerve agent detection was performed by BN nanoclusters using density functional theory (DFT) calculations. The obtained findings indicate no considerable interaction between B24N24 nanocluster and sarin molecule. Thus, pure B24N24 is not highly sensitive against sarin’s presence regarding weak interactions (−7.68 kcal mol−1). To construct a more suitable BN nanocluster for detection, sarin was adsorbed on the AlB23N24 and GaB23N24 nanoclusters. The investigated adsorption energy of sarin on the AlB23N24 and GaB23N24 surface was −43.91 and −31.83 kcal mol−1, respectively. After adsorption of sarin on the AlB23N24 and GaB23N24, the calculated change in electrical conductivity were 21.59% and 29.01%, respectively. Therefore, a considerable change in electrical conductivity (σ) of AlB23N24 and GaB23N24 was observed while the change of B24N24 is negligible. This change in conductivity can be considered a signal to detect the sarin. However, electrical conductivity in AlB23N24 and GaB23N24 indicated an ideal change but only GaB23N24 nanocluster indicated a suitable short recovery time (approximately 0.03 s for sarin desorption). The UV–vis spectra analysis shows that the sarin/GaB23N24 complex exhibits a blue shift toward lower wavelengths. These results show that it is possible to utilize the GaB23N24 for the detection of toxic sarin molecule.
... There are many studies about the identification of CWC-related compounds in the literature [9,[20][21][22][23][24][25][26][27][28]. Although detailed validation studies have been reported for quantitative analysis, limit of detection, precision (by relative standard deviation or standard deviation) and %recovery studies were performed for qualitative analysis. ...
Performing a detailed qualitative validation, which is carried out by many laboratories in the forensic community, has been the main goal of this study. In this study, a proper and systematic qualitative method validation procedure was proposed, and its application was shown on the analysis of Chemical Weapon Convention (CWC) related compounds in organic samples. All validation steps were described in detail. The study was carried out in pump oil and dichloromethane (DCM). The limit of detection values were determined for each compound and were found in the range of 0.5 – 2.0 µg mL⁻¹ in pump oil and 0.08 – 1.5 µg mL⁻¹ in DCM. The validation parameters were calculated, such as the rates of sensitivity, selectivity, false-negative, false-positive, also accordance and concordance. The predicted and obtained results were compared by using Cohen's Kappa Coefficient Test, and the compatibility of the results was found as "very good". After the validation procedure, all of the validation results were evaluated, and the proposed method was confirmed as appropriate for the analysis of CWC-related compounds in organic samples. The applicability of the validated method was proved by determining the CWC-related compounds in organic samples provided by the Organization for the Prohibition of Chemical Weapons during proficiency tests.
... DMMP as a common additive for stabilizers, textile and anti-electricity emollients, anti-foaming agents, emollients has become an important environmental contaminant and food chain because it is widely consumed [9]. The detection of CWA's has been proven possible by a number of techniques such as gas chromatography [10], liquid chromatography [11], gas chromatography-mass spectroscopy (GC-MS) coupled method [12], ion mobility spectroscopy [13], atomic emission detection (AED) [14], Fourier transform infrared (FTIR) spectroscopy [15], Raman spectroscopy [16], and capillary electrophoresis (CE) [17]. These techniques have been shown to possess high sensitivity, precision, and accuracy, however, prove to pose challenges during field application due to the expense of the; equipment, technical training, and time required to complete the analysis. ...
The external electric field can effectually enhance the electronic and optical features of low dimensional systems. Hence, the corresponding atomic structure and adsorption feature changes of a B12N12 fullerene under different applied external electric fields for dimethyl methylphosphonate (DMMP) detection were evaluated. The adsorption of DMMP on the B12N12 surface has been calculated using density functional theory (DFT) and time dependent density functional theory (TDDFT) by the PBE (Perdew-Burke-Ernzerhof) functional to study the effects of the parallel (EX) and transverse (EY) external electric fields on the structural and optoelectronic features of the pure fullerene. Through the analysis of the binding energy it is found that B12N12 fullerenes, in the presence of a parallel external electric field (EX = 0.15 a.u.), are energetically favored when compared to B12N12 fullerenes in the presence of a transverse external electric field (EY = 0.15 a.u.). The results demonstrate that a transverse external electric field ranging from 0.005 a.u. to 0.015 a.u. could enhance the DMMP sensitivity of the B12N12 fullerene (with a significant reduction of energy band gap), which potentially could aid in the development of a room temperature DMMP gas sensor. The adsorption and desorption of DMMP could be controlled by external electric field too, which has the potential for applications in itself, relative to DMMP collection and storage.
... In 1990, a review of chromatographic methods applied to the determination of both intact CWAs and their markers with the use of flame-photometric, nitrogen-phosphorus, atomic-emission, photoionization, and mass-spectrometric detectors was published [21]. Publications devoted to the use of FTIR-spectrometric [22][23][24][25], mass-spectrometric [26][27][28], and other spectral detectors [29][30][31][32][33][34] for these purposes appeared more recently. ...
... Traditional gas sensing technologies such as gas chromatography, ion mobility spectroscopy and infrared spectroscopy have achieved low-concentration gas detection, but they require the use of bulky and expensive instruments and complicated analysis, resulting in low-efficiency and time-consuming [9][10][11]. Advances in semiconductor technology [12,13] and the design of nanomaterials [14][15][16][17][18] are paving the path for the development of next-generation gas sensors that can outperform commercial analytical instruments in future. ...
In this paper, a novel ammonia detection hybrid film is proposed based on a graphene oxide (GO)/graphene stack, which shows excellent sensing characteristics at room temperature. It is attributed to the cooperation of GO layer serving as molecular capture layer while graphene serving as conductive layer. GO layer is obtained on chemical vapor deposited graphene film by a simple drop-casting method. The prepared GO/graphene hybrid film is directly transferred to the target substrate without any additional transfer vehicle to reduce possible contamination. The success of the transfer depends on the mechanical strength of GO layer. The thickness of GO layer can scale down to 55 nm while sustaining the transfer process. The best ammonia gas sensing performance is obtained at about 275 nm GO layer thickness and the ammonia detection limit is calculated to be 1.5 ppb. In conclusion, the ammonia gas sensing performance of GO/graphene hybrid film can be significantly improved through GO layer thickness optimization.
... CWAs have been widely used/are claimed to be used in many conflicts [130], notable examples being during WWI and Vietnam War. Lewisite (C 2 H 2 AsCl 3 ) is a blister agent that had been developed during WWI and has still been in use during the Iran-Iraq War [11,132]. Yprite (C 4 H 8 Cl 2 S), also known as mustard gas or sulfur mustard, is another well-known blister agent that had been used first time during WWI in Belgium and has been still in use during Iran-Iraq War [64,127]. ...
Military activities drastically affect soil properties mainly via physical/chemical disturbances during military training and warfare. The present paper aims to review (1) physical/chemical disturbances in soils following military activities, (2) approaches to characterization of contaminated military-impacted sites, and (3) advances in human health risk assessment for evaluating potential adverse impacts. A literature search mainly covering the period 2010-2020 but also including relevant selected papers published before 2010 was conducted. Selected studies (more than 160) were grouped as follows and then reviewed: ~40 on the presence of potentially toxic elements (PTEs), ~20 on energetic compounds (ECs) and chemical warfare agents (CWAs), ~40 on human health risk assessment, and generic limits/legislation, and ~60 supporting studies. Soil physical disturbances (e.g. compaction by military traffic) may drastically affect soil properties (e.g. hydraulic conductivity) causing environmental issues (e.g. increased erosion). Chemical disturbances are caused by the introduction of numerous PTEs, ECs, and CWAs; and are of wide nature. Available generic limits/legislation for these substances is limited, and their content do not always overlap. Among numerous PTEs in military-impacted zones, Pb seems particularly problematic due to its high toxicity, abundance, and persistence. For ECs and CWAs, their highly variable physiochemical properties and biodegradability govern their specific distribution, environmental fate, and transport. Most site characterization include proper spatial/vertical profiling, albeit without adequate consideration of contaminant speciation/fractionation. Human health risk assessment studies generally follow a well-agreed framework; however, the depth/adequacy of its use varies. Generic limits/legislation limited to a few countries do not always include all contaminants of concern, their content don’t overlap, and scientific basis is not always clear. Thus, a comprehensive scientific framework covering a range of contaminants is needed. Overall, contaminant speciation, fractionation, and mobility have not been fully considered in numerous studies. Chemical speciation and bioaccessibility, directly affecting results for risk characterization, should be properly integrated into risk assessment processes for accurate results.
... Cyclosarin (GF) is a highly toxic organophosphate that belongs to the member of nerve used in the Gulf War (GW) operations [3,4]. Various methods introduced for nerve agent detection including chromatography [5], mass spectroscopy [6], photoluminescent [7] and fluorescent sensors [8]. By the advent of nanotechnology, nanostructures have attracted an extensive attention as gas sensors because their surface/volume ratio is much higher than that of the conventional micro sensors which makes the large adsorption area available for adsorption process [9][10][11][12][13][14][15][16][17][18]. ...
To find a chemical sensor for detection of Cyclosarin (GF) nerve agent, we studied its interaction with B24N24, AlB23N24, B16N16 and AlB15N16 nanoclusters by means of density functional theory calculations. All calculations were investigated whit the M06 method and 6-311G(d,p) basis set. It was demonstrated that the interaction of GF with AlB23N24 and AlB15N16 is more stable than that of the B24N24 and B16N16. Thermodynamic parameters indicated that the AlB23N24 and AlB15N16 interactions with the GF are exothermic and spontaneous. Despite both AlB23N24 and AlB15N16 demonstrated strong adsorption, the electronic properties calculation indicated that AlB15N16 sensitive to the nerve agent adsorption. Our results predicted AlB15N16 has good potential as a sensor for the detection of GF.
... Other organophosphate compounds of significant concern are G-and Vseries CWAs. Efforts to detect and eradicate CWAs in wartime and civilian environments have prompted extensive studies of their environmental persistence, chronic effects, and degradation/metabolic products [24][25][26]. In the presence of water, many CWAs hydrolyze rapidly and can be difficult to detect as the parent compound [27]. ...
There is a significant concern about the accumulation of hazardous chemicals in the environment. Pharmaceuticals and drugs of abuse (DOA) can reach high levels in waste water and industrial or hospital effluents, for example. Another group of chemicals of concern are organophosphate compounds. Although the stockpiling and manufacture of chemical warfare agents (CWA) has substantially decreased due to the Chemical Weapon’s Convention, nerve agents continue to be used by rogue states and other actors. In this study, two paper spray MS screening procedures were developed to detect these hazardous chemicals in soil without sample preparation. Central nervous system (CNS) depressants, opiates, stimulants, and tricyclic antidepressants were included in the pharmaceutical/DOA screening method. Chemical warfare simulants and hydrolysis products were analyzed using a separate screening method which utilized polarity switching to detect positive and negative ions associated with this class of molecules. For both methods, an aliquot of soil was weighed into a well pressed against the paper spray substrate. A dual extraction/spray solvent was then applied to the soil, extracting the analytes and facilitating electrospray ionization from the paper. A quadrupole-orbitrap mass spectrometer was utilized in MS/MS mode for detection. Limits of detection for the pharmaceuticals and DOA ranged between 0.3 and 40 ng/g for three different soil types. The CWA simulants had limits of detection of 50 ng/g while the hydrolysis products were detected between 1 and 5 ng/g. In order to improve quantitative performance, an offline salting out liquid-liquid (SALLE) extraction with internal standardization was also performed.
... La littérature présente de nombreux autres exemples de séparation par chromatographie en phase gazeuse 53,54,55,56 . A ce titre, l'un des résultats les plus bas en termes de seuil de détection a été obtenu par l'équipe de Y. Zou 57 avec 1 ppt pour le diméthylméthylphosphonate (DMMP), un simulant particulièrement adapté pour les agents de guerre. ...
Le développement d’un système de détection sensible, sélectif, rapide, fiable et portable à coût modéré est devenu une nécessité pour prévenir le risque chimique lors d’attaques operationnelles ou terroristes potentielles. Ainsi, ce projet porte sur l’élaboration d’un capteur pour la détection d’agents chimiques de guerre de type organophosphorés (Sarin, Tabun, Soman, VX). L’utilisation de microleviers comme capteur pour augmenter la sensibilité est une méthode prometteuse. La surface faible des microleviers conventionnels limite, la sensibilité de la méthode. Ainsi, pour augmenter la surface de capture, nous avons crée un réseau de nanotubes de TiO2 verticalement alignés. Cette nanostructuration est réalisée par une anodisation électrochimique d’une couche de titane pour obtenir les nanotubes de TiO2. L’influence des paramètres du dépôt de titane et de l’anodisation a été optimisée sur des surfaces modèles puis les conditions ont été transferées sur les microleviers. Afin d’augmenter la sélectivité des capteurs (mais aussi la sensibilité) une fonctionnalisation a été réalisée avec une famille originale de ligands bifonctionnels capables de promouvoir la reconnaissance moléculaire des composés organophosphorés cibles et adaptés à la liaison avec une surface de TiO2.
... These techniques have certain advantages and drawbacks when used to detect nerve agent molecules. Almost all of these instruments have been discussed at length in various publications, and in numerous applications since the 1990's [49]. Nonetheless, they are unable of being used solely to detect all the various CWA molecules and have to be combined with other techniques to give lower and more reliable detection limits [50]. ...
This review encompasses a literature review of chemical warfare agents (CWAs) and the attendant advantages and limitations of existing techniques (i.e. gas chromatography, liquid chromatography and ion mobility spectrometry) used for the detection of CWAs in previous decades. CWAs include the following agent classes i.e. nerve agents, blister agents, blood agents and incapacitating agents. Nerve agents are among the most toxic and have been used by certain military forces and terrorists in many conflicts and consequently have caused both death and disability to humans. Here, we focus on current developments in biosensor approaches used for the detection of organophosphorus CWAs, especially those that are able to overcome the limitations found in earlier detection techniques. The biosensor approach offers rapid, sensitive, selective, portable, simple and low-cost on-site detection capability that would meet the requirements for CWA detection in the event of future events. The future prospects and challenges of biosensor development for CWA detection is also discussed.
... Alkylphosphonic acids, the nerve agents' hydrolysis degradation products, are specific to their parent nerve agents, and can also be used for such identifications in environmental samples [13]. The developed detection techniques include infrared spectroscopy, ion mobility spectroscopy, capillary electrophoresis (CE), GC-MS, and LC-MS [14,15]. ...
The rapid and reliable detection of chemical and biological agents in the field is important for many applications such as national security, environmental monitoring, infectious diseases screening, and so on. Current commercially available devices may suffer from low field deployability, specificity, and reproducibility, as well as a high false alarm rate. This paper reports the development of a portable lab-on-a-chip device that could address these issues. The device integrates a polymer multiplexed microchip system, a contactless conductivity detector, a data acquisition and signal processing system, and a graphic/user interface. The samples are pre-treated by an on-chip capillary electrophoresis system. The separated analytes are detected by conductivity-based microsensors. Extensive studies are carried out to achieve satisfactory reproducibility of the microchip system. Chemical warfare agents soman (GD), sarin (GB), O-ethyl S-[2-diisoproylaminoethyl] methylphsophonothioate (VX), and their degradation products have been tested on the device. It was demonstrated that the device can fingerprint the tested chemical warfare agents. In addition, the detection of ricin and metal ions in water samples was demonstrated. Such a device could be used for the rapid and sensitive on-site detection of both chemical and biological agents in the future.
... Alkylphosphonic acids, the nerve agents' hydrolysis degradation products, are specific to their parent nerve agents, and can also be used for such identifications in environmental samples [13]. The developed detection techniques include infrared spectroscopy, ion mobility spectroscopy, capillary electrophoresis (CE), GC-MS, and LC-MS [14,15]. ...
... Accordingly, analytical tools that can selectively and sensitively detect these kinds of chemical weapons have been developed for the defense, detoxification, and safe management [3][4][5]. Instrument-based methods, such as mass spectrometry, ion-mobility spectroscopy, and photonic crystals, have been used for the sensing, but these methods have several limitations, such as low sensitivity, limited selectivity, time-consuming process, operational complexity, additional sample pre-treatment steps, and non-portability for real-time on-site application [6][7][8][9][10][11]. In this aspect, fluorogenic and chromogenic molecular sensing systems have gained attention due to their advantages for overcoming the limits of current methods [12][13][14][15]. ...
Diethylcyanophosphonate (DCNP) is a simulant of Tabun (GA) which is an extremely toxic chemical substance and is used as a chemical warfare (CW) nerve agent. Due to its toxic properties, monitoring methods have been constantly come under the spotlight. What we are proposing within this report is a next-generation fluorescent probe, DMHN1, which allows DCNP to become fully traceable in a sensitive, selective, and responsive manner. This is the first fluorescent turn-on probe within the dipolar naphthalene platform induced by ESIPT (excited state intramolecular proton transfer) suppression that allows us to sense DCNP without any disturbance by other similar G-series chemical weapons. The successful demonstrations of practical applications, such as in vitro analysis, soil analysis, and the development of an on-site real-time prototype sensing kit, encourage further applications in a variety of fields.
... Mass spectrometry alone or in combination with chromatography are universal tools for the purpose of specific structures identification and are suitable for the determination of viral, bacterial and toxin agents [8][9][10][11][12]. Applicability for the identification of chemical agents by the same equipment is another advantage of mass spectrometry [13,14]. ...
Biosensors are analytical devices combining a physical sensor with a part of biological origin providing sensitivity and selectivity toward analyte. Biological warfare agents are infectious microorganisms or toxins with the capability to harm or kill humans. They can be produced and spread by a military or misused by a terrorist group. For example, Bacillus anthracis, Francisella tularensis, Brucella sp., Yersinia pestis, staphylococcal enterotoxin B, botulinum toxin and orthopoxviruses are typical biological warfare agents. Biosensors for biological warfare agents serve as simple but reliable analytical tools for the both field and laboratory assay. There are examples of commercially available biosensors, but research and development of new types continue and their application in praxis can be expected in the future. This review summarizes the facts and role of biosensors in the biological warfare agents’ assay, and shows current commercially available devices and trends in research of the news. Survey of actual literature is provided.
... The common chemical warfare agents have varying degrees of volatility and dose, both a vapor hazard as well as a liquid contact hazard. This physical characteristic has made the analysis of chemical warfare agents amenable to the analytical techniques commonly employed for most environmental analyses, namely gas chromatography (GC) and liquid chromatography (LC) with a variety of detectors including mass spectrometry (MS) [3][4][5]. ...
... The reliable detection of chemical warfare agents (CWAs) such as sulfur mustard, 27 lewisite or nerve agents has been driving intensive research efforts in the last two 28 decades. The two main applications are, on the one hand, the sensitive analysis 29 of CWAs and their decomposition products in environmental samples [1] and, on 30 the other hand, the biomonitoring of CWAs [2]. The most evolved technologies 31 currently available are best suited for the retrospective detection exposure to CWAs. ...
Fast, real-time and reliable detection of Chemical Warfare Agents (CWAs) is one of the most important challenges for our societies. The common techniques used to detect CWAs are expensive and require trained personnel, such as gas or liquid chromatography coupled to mass spectrometry or ion mobility spectrometry. For that reason, a lot of research has been conducted in recent years to achieve low-cost and portable technology for monitoring the presence of CWAs in the local environment. According to reported results, carbon nanomaterials have been found to be promising sensitive materials due to their excellent electronic properties and high possibilities for being functionalized, decorated or modified, this achieving tailored surface chemistry. In this chapter we study the use of different carbon nanomaterials (carbon nanotubes, graphene, carbon nanofibers and carbon black) to detect compounds with intrinsic potential to be used as a chemical weapon against military or civilian’s targets. The available technology usually employs chemiresistive, electrochemical, gravimetric and optical sensors to measure the concentration of CWAs at ppm or ppb levels in the environmental or in biological samples. The suitable detection of chemical agents employing inexpensive sensors constitutes an important strategy to enhance population security.
... [23][24][25] Their residues in agricultural products and groundwaterp ose ap otential threat to human health, causing problemss uch as eye pain, abdominal pain, convulsions, and respiratory failure. [26][27][28] Indeed, the high toxicity of OPs to humans had inspired their use as chemical warfare agents( e.g.,t he G-and V-series nerve agents). [29][30][31][32] Mechanistically,t hese pesticides inhibitt he activity of the enzyme acetyl cholinesterase, which causes toxic accumulation of the neurotransmitter acetylcholine and resultsi n seriousu ncontrollable musclec ontractions. ...
Herein, a catalytic chemosensing assay (CCA), based on a bimetallic complex, [RuII(bpy)2(CN)2]2(CuII)2 (bpy=2,2′‐bipyridine), is described. This complex integrates a task‐specific catalyst (CuI‐catalyst) and a signaling unit ([RuII(bpy)2(CN)2]) to specifically hydrolyze methyl parathion, a highly toxic organophosphate (OP) pesticide. The bimetallic complex catalyzed the hydrolysis of the phosphate ester to generate o,o‐dimethyl thiophosphate (DTP) anion and 4‐nitrophenolate. Intrinsically, 4‐nitrophenolate absorbed UV/Vis light at λmax=400 nm, creating the first level of the chemosensing signal. DTP interacted with the original complex to displace the chromophore, [RuII(bpy)2(CN)2], which was monitored by spectrofluorometry; this was classified as the second level of chemosensing signal. By integrating both spectroscopic and spectrofluorometric signals with a simple AND logic gate, only methyl parathion was able to provide a positive response. Other aromatic and aliphatic OP pesticides (diazinon, fenthion, meviphos, terbufos, and phosalone) and 4‐nitrophenyl acetate provided negative responses. Furthermore, owing to the metal‐catalyzed hydrolysis of methyl parathion, the CCA system led to the detoxification of the pesticide. The CCA system also demonstrated its catalytic chemosensing properties in the detection of methyl parathion in real samples, including tap water, river water, and underground water.
... Gas chromatography coupled to mass spectrometry (GC/MS) is the most reliable and primary analytical technique used for retrospective detection and identification of CWAs. 11,12 Direct analysis of contaminated organic samples leads to false negative results and creates difficulties in identification because analyte peaks are masked by the coeluting background peaks. 13 Therefore, extraction and sample cleanup are essential before analysis. ...
Extraction of vesicant class of chemical warfare agents (CWAs) such as sulfur mustard and nitrogen mustards from the environmental matrices is of prime importance, from a forensic and verification viewpoint of the Chemical Weapons Convention (CWC). For extraction of Convention Related Compounds from nonpolar organic medium, commercially available silica cartridges are used extensively, but silica cartridges exhibit limited efficiency toward vesicant classes of compounds. It is expected that sulfur mustard being nonpolar does not retain sufficiently on silica surface, and nitrogen mustards (being basic) are strongly adsorbed on acidic silica surface, resulting in their poor recoveries. Contrary to the expected higher recovery of sulfur mustard over nitrogen mustards, it was observed that the recovery of sulfur mustard was lower than that of nitrogen mustards with the silica based sorbent. The reason for this typical behavior of these agents on silica was investigated. This study was aimed to develop an analytical method for efficient extraction and enrichment of sulfur and nitrogen mustards from hydrophobic matrices. In this work, the polymeric sorbent was synthesized with polar methacrylic acid (MAA) as monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker and used for solid phase extraction (SPE) of sulfur mustard and nitrogen mustards. The extraction efficiency of the polymeric sorbent was optimized and compared with that of silica cartridges. Both classes of analytes were recovered in good amounts from the polymeric sorbent compared to silica. The extraction parameters were optimized for the proposed method which included extraction solvent ethyl acetate and washing solvent n-hexane (1 mL). The recoveries of the analytes ranged from 75 to 87% with relative standard deviations (RSDs) lower than 9%. The limit of detection (LOD) was found to be in the range of 0.075-0.150 μg mL-1, and limit of quantification (LOQ) was >0.25 μg mL-1. The linear dynamic range of optimized method was found to be 0.50-20 μg mL-1 ( r2 = 0.9994) for sulfur mustard and 0.25-20 μg mL-1 ( r2 = 0.9897-0.9987) for nitrogen mustards, respectively.
... To identify the products, gas chromatography coupled with atomic emission spectrometry was used. A gas chromatograph equipped with an atomic emission detector (GC/AED) is particularly useful, because it enables not only the components of a sample to be separated and their elemental composition to be determined, but also their approximate empirical formulas to be calculated [9][10][11][12][13]. ...
Reactions of sulfur mustard with active components of decontaminants ORO and C9 (Polish abbreviations of organic decontaminating solutions) were studied and their products were identified by GC/AED. Quantitative determinations of individual products in the reaction mixtures allowed to evaluate the kinetic parameters of the mustard reactions. The major decontamination product was divinyl sulfide, the product of the elimination reaction. At certain proportions of mustard to the decontaminant's active component, substitution products were also formed.
... The analysis of CWA and their degradation products is well developed and widely used in many laboratories. [1][2][3][4][5][6] Significantly less attention is paid to the chemical substances used to produce CWA. In terms of monitoring of the compliance with the Convention's provisions, the identification of these substances is as important as the identification of the CWA itself. ...
Recent advances in analysis of precursors, simulants and degradation products of chemical warfare agents (CWA) are reviewed. Fast and reliable analysis of precursors, simulants and CWA degradation products is extremely important at a time, when more and more terrorist groups and radical non-state organizations use or plan to use chemical weapons to achieve their own psychological, political and military goals. The review covers the open source literature analysis after the time, when the chemical weapons convention had come into force (1997). The authors stated that during last 15 years increased number of laboratories are focused not only on trace analysis of CWA (mostly nerve and blister agents) in environmental and biological samples, but the growing number of research are devoted to instrumental analysis of precursors and degradation products of these substances. The identification of low-level concentration of CWA degradation products is often more important and difficult than the original CWA, because of lower level of concentration and a very large number of compounds present in environmental and biological samples. Many of them are hydrolysis products and are present in samples in the ionic form. For this reason, two or three instrumental methods are used to perform a reliable analysis of these substances.
... As CBR forensic analysis can be expected to take Wear protection contingency for chemical, bacteriological, radiological, and nuclear crime scene management. a long time (Kientz, 1998;Rahni, 2002;Horita and Vass, 2003), traditional trace evidence could speed the implementation of countermeasures (Fig. 8.3.2), although priority is given to the decontamination procedure even if it might damage evidence (Vogt and Sorensen, 2002). ...
... For instance, ammonia emissions are associated with presence of secondary airborne particulate matters in cars exhaust, explosions in case of leakage in chemical plants for fertilizer production, freshness indicator for spoilage of meats and fish and medical diagnosis of peptic ulcers and renal/liver diseases. For such applications, the use of traditional analytical techniques, such as gas chromatography [2,3], ion mobility spectroscopy [4], or mass spectrometry [5,6] for ammonia detection is limited because of the impracticality associated with the slow response time and the large size of these instruments. Accordingly, there is a need to develop cost-effective ammonia sensing technologies that are suitable for routine sampling and detection of ammonia gas to eventually allow for continuous monitoring of ammonia emissions. ...
Recently, there is an increasing interest in ammonia sensing and detection for a wide range of applications, including food, automotive, chemical, environmental, and medical sectors. A major challenge is to obtain selective, sensitive and environmentally stable sensing polymer/chemical materials that can meet the stringent performance requirements of these application areas. Among various polymer-based sensing materials, polyaniline has emerged as a preferred choice owing to its cost-effectiveness, facile preparation steps, and superior sensing performance towards ammonia.
In this review, advances in polyaniline based ammonia detection sensors are summarized, with a special focus on progresses in polyaniline modification techniques to achieve enhanced sensing performance. These techniques utilize interfacial and high dilution syntheses, multifunctional dopants, template synthesis, self-oxidizing template synthesis, etc., methods Most up-to-date developments in combining polyaniline with other ammonia sensing materials, including polyaniline nanocomposites with metal oxides, graphene, carbon nanotubes and other carbon nanomaterials, are included. These novel nanocomposites have special capabilities of forming p-n nanojunctions or electron interphase interactions for superior detection sensitivity and selectivity. In addition, existing challenges toward understanding, reproducing, and optimizing the design of polyaniline based ammonia sensors are discussed.
Chemical weapons continue to be an ongoing threat that necessitates the improvement of existing detection technologies where new technologies are absent. Lower limits of detection will facilitate early warning of exposure to chemical weapons and enable more rapid deployment of countermeasures. Here, we evaluate two colorimetric gas detection tubes, developed by Draeger Inc., for sarin and sulfur mustard chemical warfare agents and determine their limits of detection using active chemical agent. Being that commercial companies are only able to use chemical agent simulants during sensor development, it is imperative to determine limits of detection using active agent. The limit of detection was determined based on the absence of a reasonably perceptible color response at incrementally lower concentrations. A chemical vapor generator was constructed to produce stable and quantifiable concentrations of chemical agent vapor, with the presence of chemical agent verified and monitored by a secondary detector. The limits of detection of the colorimetric gas detection tubes were determined to be 0.0046 ± 0.0002 and 2.1 ± 0.3 mg/m3 for sarin and sulfur mustard, respectively. The response of the sarin detection tube was readily observable with little issue. The sulfur mustard detection tube exhibited a weaker response to active agent compared to the simulant that was used during development, which will affect their concept of operations in real-world detection scenarios.
Sulfur mustard (SM) is an important chemical warfare agent (CWA) and has been used frequently in various conflicts. It is important to develop a facile, rapid, sensitive and selective detection method for SM. In this work, we constructed a novel fluorescent probe PCS capable of generating active sensing species for rapid and selective detection of SM and its simulant CEES (2-chloroethyl ethyl sulfide). PCS exhibits excellent chemical and photostability and can generate reactive species in situ for rapid (within 90 s, at 60 °C) and selective detection of SM and CEES in solution with high sensitivity (∼nM level). Moreover, PCS could enable the detection of mustards in situ. A test strip with PCS and KOH was prepared and realized the sensitive and selective detection of CEES in the gas phase. In addition, the PCS probe can realize facile and rapid detection of CEES-contaminated surfaces by spraying its sensing system (ethanol solution containing PCS and KOH). The sensing mechanism was well demonstrated through the separation and characterization of the sensing product.
In the field of Chemical Defense toward Nerve Agents, the development of analytical methodologies for analysis of different sample matrices, training of human resources in handling, detection of such toxic chemicals, and design of more effective medical countermeasures may be hampered by the lack of infrastructure and well-prepared human resources. Therefore Nerve Agents Surrogates may be an invaluable alternative to accomplish such tasks, as these compounds present similar behavior and are easier to handle in comparison to actual nerve agents, being useful analytical and toxicological tools for technical purposes.
Chemical warfare (CW) is undoubtedly one of the most devastating weapons as compared to biological and nuclear warfare of mass destruction invented by humans. They are extremely hazardous chemicals that may be dispersed as aerosol or liquid, gas, and agents. These CW agents are either fatal or inefficient on humans. Many harmful substances are well known in the environment, but only a few of them are considered CW agents depending on their properties like the speed of action after diffusion and persistence, and high toxicity. They are cheap and easy to prepare, allowing even small terrorist gangs to cause huge casualties with a small amount. This chapter discusses the characteristics of several CW agents as well as symptoms, side effects, and the organic compounds used as medical equipment for the treatment of CW agent exposure.
Chemical warfare agents (CWAs) induce illness and/or death not only for human beings but also for animals and plants. The explosive compounds, heavy metal ions, and radioactive and organophosphorus compounds are employed in CWAs. The threat posed by CWAs and limitations of a process to recognize them supports the necessity for the sustained design of sensing systems. Moreover, simplicity is very important in determining a target analyte and there is a huge need for novel sensing methods development with smart abilities in homeland security and defense applications for CWAs detection. Sensors are detection means that have noteworthy features such as quick, portable, selective, and sensitive. Nanomaterial-enable sensor platforms are being designed for multiplex-functionality, high-flexibility, and high-efficiency sensing applications. In this chapter, we overview the CWAs and highlight the wide and recent applications of plasmonic nanosensors for CWA.
Herein, a novel blue aggregation-induced enhanced emission (AIEE) material 4-N-(naphthalen-l-yl)-3,5-bis(4-N-phenyl-1-naphthylamine)phenyl-4H-1,2,4-triazole (NDTAZ) is developed and used as a fluorescent chemosensor for sulfur mustard (SM) simulant 2-chloroethyl ethyl sulfide (2-CEES) vapor. The NDTAZ chemosensor is designed by introducing an electron-donating N-phenyl-1-naphthylamine group at 3 and 5 position of 4H-1,2,4-triazole (TAZ) to enhance the nucleophilicity of the TAZ group, and a naphthalene ring is connected to 4 position of the TAZ group to construct an AIEE molecule. The NDTAZ films show extraordinary stability and then are further used as reliable and portable fluorescent chemosensors. Upon exposure to 2-CEES vapor, the NDTAZ chemosensor exhibits an instantaneous fluorescence response (not more than 1 s). What should be noted is that this fluorescent chemosensor realizes the visualized detection of fluorescent color change from blue to green at "room temperature", which is rarely reported. The limit of detection is estimated to be 0.55 ppm, which is below the AEGL-1 (0.6 ppm for 1 min) safety ceiling level to SM exposure. Moreover, the NDTAZ chemosensor shows high selectivity toward 2-CEES vapor over closely related substances, including alkylating agents, aryl halide compounds, sulphur-containing compounds, and nerve agent mimics. More impressively, the NDTAZ chemosensor demonstrates good recyclability by water treatment. Also, the sensing mechanism is adequately proved by using multiple experimental methods and theoretical calculation. In addition, the NDTAZ-based facile filter paper-constructed test strips are fabricated for real-time and on-spot detection of leaked 2-CEES gas specifically. Therefore, this fluorescent chemosensor with excellent sensing performance greatly advances the practical detection of SM species at room temperature.
A thermal desorption associative ionization time-of-flight mass spectrometer was developed for ultrasensitive detection of semi-volatile chemical warfare agents (CWAs). The excited-state CH2Cl2-induced associative ionization method presented a soft ionization characterization and an excellent sensitivity towards CWAs. The detection sensitivities of the investigated nine CWA-related substances were 2.56 × 10⁵–5.01 × 10⁶ counts ng⁻¹ in a detection cycle (30 s or 100 s). The corresponding 3σ limits of detection (LODs) were 0.08–3.90 pg. Compared with the best-documented LODs via the dielectric barrier discharge ionization (DBDI) and secondary electrospray ionization (SESI), the obtained LODs of the investigated compounds were improved by 2–76 times. Additionally, the measured sensitivity of 2-Chloroethyl ethyl, a proxy for mustard gas, is 550 counts pptv⁻¹, which exceeds the DBDI and SESI's corresponding values (4.4 counts pptv⁻¹ and 6.5 counts pptv⁻¹) nearly by two orders of magnitude. A field application simulation was conducted by putting a strip of PTFE film contaminated with the CWA-related agent into the thermal desorption unit. The simulation showed that the sensitivities of the instrument via swipe surveying could achieve 2.19 × 10⁵ to 5.23 × 10⁶ counts ng⁻¹. The experimental results demonstrate that the excited-state CH2Cl2-induced associative ionization is an ultrasensitive ionization method for CWAs and reveal a prospect for improving the detection of CWA species future.
ZnO is known as a promising material for surface acoustic wave (SAW) sensor devices because of its piezoelectric property. Recently, quartz crystal microbalances (QCMs) have been promising as a sensor platform due to their high sensitivity and ease of measurement. In particular, the alignment of ZnO nanosheets (NSs) into ordered nanoarrays is expected to improve the device sensitivity and stability due to large specific surface area, which allows the captured significant quantities of gas molecules. In this study, we fabricated a quartz crystal microbalance sensor with ZnO NSs structures using polyvinylidene fluoride as a receptor for nerve agent detection. We synthesized two-dimensional NSs by chemical bath deposition (CBD) via the potassium hydroxide etching method. CBD is an excellent method that can easily form uniform structures at low cost. We fabricated ZnO NSs modified with polyvinylidene fluoride and used it for detection of dimethyl methylphosphonate (DMMP) gas. The NSs structure indicated that, when a similar functional group material is coated, the specific surface area increased compared to the nanorods (NRs) structure. As a result, the sensitivity of the quartz crystal microbalance sensor to DMMP gas was improved.
Sulfur mustard (SM, also called as mustard gas (HD)) is a persistent and highly toxic gas used as chemical weapon in wars and military conflicts. Moreover, owing to its simple structure and easy synthesis, it is the most likely chemical agent used by terrorists. For this reason, it is vital important to develop a facile, rapid and reliable detection system for SM. In this paper, we have developed four quinoline-2-thiones as fluorescent probes, 2a-2d, for the detection of SM and its analogues, half sulfur mustard (CEES) and a nitrogen mustard NH1. In the presence of KOH, these quinoline-2-thiones deprotonated to quinoline-2-thiophenol anions, which react with SM and its analogues rapidly to form quinoline-2-thiethers with highly efficient fluorescence, giving turn-on fluorescence response. The sensing products with CEES were isolated and fully characterized, thereby, the sensing mechanism was firmly established. The fluorescent probes with 4-trifluoromethyl group, 2b and 2d, exhibit rapid response to SM, CEES and NH1 (within 1 min at 60°C for CEES and NH1), high sensitivity (limit of detection, 50 nM for SM and 20 nM for NH1) and high selectivity. Furthermore, polymer film test strips were fabricated with probe-embedded poly(ethylene oxide) for the detection of CEES vapor. These test strips displayed a rapid response (<4 min) to gaseous CEES with high sensitivity (0.2 ppm) and high selectivity. These results show that fluorescent probes 2b and 2d have a good application prospect in the field detection of mustard gas.
We have explored a novel turn-on fluorescence detection of sulfur mustard (SM) at "room temperature". The innovative protocol that uses the combination of luminol and an ionic liquid in water exhibits fluorescence detection of SM within seconds. In this simple, fast, and low-cost chemosensing method, luminol acts as the receptor as well as a signaling element, and the ionic liquid (1-ethyl-3-methylimidazolium dicyanamide) provides the requisite and polarizing medium to realize the detection at "room temperature". Interestingly, with a higher concentration of a probe (0.56 mM), SM sensing can be visualized with the naked eye, leading to the formation of a fluorescent green color within a minute, thus expanding the application of the developed sensing technique for chromo-fluorogenic detection of SM. Excellent selectivity, sensitivity (LOD: 6 ppm), and chemosensing at ambient temperature make this methodology completely field-deployable.
Graphene nanosheets are widely used for designing functional nanocomposite sensors that are highly sensitive. In this study, nitrogen‐doped reduced graphene oxide (N‐rGO) polyaniline (PANI) nanocomposites composed of localized heterojunctions are prepared for the detection of ammonia, dimethylamine, and trimethylamine gases with superior sensing performances. rGO nanosheets with electrical properties modified via N‐doping are strategically incorporated in p‐type PANI via in situ synthesis, with the nanosheets acting as templates for PANI growth. N‐rGO nanosheets featuring large specific area, high electrical conductivity, and n‐type semiconductive behavior combined with the attractive electrical p‐type characteristics of PANI are found to be highly beneficial for improving detection sensitivity toward ammonia, dimethylamine, and trimethylamine gases at 25 °C. Overall, the detection sensitivity of the advanced N‐rGO nanocomposites is more than two times higher than that of PANI alone. Moreover, the N‐rGO/PANI nanocomposites reach an estimated limit of detection for ammonia gas down to the sub‐ppm range. Improvement in sensing performance is also observed for rGO/PANI and GO/PANI nanocomposites; however, the level of the improvement is less than that of N‐rGO/PANI nanocomposites. This study demonstrates the excellent potential of designing advanced graphene nanocomposite gas sensors with superior performances by manipulating the electronic properties of the graphene nanosheets.
This represents one of several sections of "A Bibliography Related to Crime Scene Interpretation with Emphases in Geotaphonomic and Forensic Archaeological Field Techniques, Nineteenth Edition" (The complete bibliography is also included at ResearchGate.net.). This is the most recent edition of a bibliography containing resources for multiple areas of crime scene, and particularly outdoor crime scene, investigations. It replaces the prior edition and contains approximately 10,000 additional citations. As an ongoing project, additional references, as encountered, will be added to future editions.
Terrorist actions, mass suicides, and "ethnic cleansings" unfortunately continue to make headlines with their massive losses of life. In the United States, the attacks on September 11, 2001 placed terms associated with terrorism within our everyday lexicon. In countries like Israel, Ireland, Lebanon and others, such terms were already in daily use. Where such news was once limited to commercial aircraft disasters or natural disasters, it seems to increasingly include the results of criminal acts requiring the services of multi-disciplinary teams of forensic experts. This section of the bibliography includes references mostly developed from the work of experts at mass graves in places like Kosovo, Rwanda, or Gautemala, or air disasters and explosions around the globe. Included among these references are those about high speed aircraft crashes involving one or two victims. Even though one or two victims may have been lost, the nature of the scene, trauma and wreckage was similar to that encountered with larger numbers of victims in commercial aircraft crashes. Not included are references to forensic engineering or mechanical aspects of mass transportation disasters. Recoveries involving known political, or human rights type, tortures of single victims are listed below. Whether the loss of life involves the search and recovery of a single victim, or those of an entire community, the disciplined and contextual collection of evidence must be carried out. For this reason, many of the resources listed in sections such as Reconnaissance, Surveying, and Mapping Techniques, or Excavation and Recovery Techniques, or Geophysical/Remote Sensing and Applications are applicable at mass fatality scenes. The use of proper search, recording, and collection protocols at many of the above ground settings demonstrates the applicability of formal archaeological techniques which were once thought only relevant in subterranean settings. The reader interested in methodologies at large scenes should review the other sections of this bibliography.
Extraction and identification of lethal nerve agents and their markers in complex organic background have a prime importance from the forensic and verification viewpoint of the Chemical Weapons Convention (CWC). Liquid-liquid extraction with acetonitrile and commercially available solid phase silica cartridges are extensively used for this purpose. Silica cartridges exhibit limited applicability for relatively polar analytes, and acetonitrile extraction shows limited efficacy toward relatively nonpolar analytes. The present study describes the synthesis of polymeric sorbents with tunable surface polarity, their application as a solid-phase extraction (SPE) material against nerve agents and their polar as well as nonpolar markers from nonpolar organic matrices. In comparison with the acetonitrile extraction and commercial silica cartridges, the new sorbent showed better extraction efficiency toward analytes of varying polarity. The extraction parameters were optimized for the proposed method, which included ethyl acetate as an extraction solvent and n-hexane as a washing solvent. Under optimized conditions, method linearity ranged from 0.10 to 10 μg mL-1 ( r2 = 0.9327-0.9988) for organophosphorus esters and 0.05-20 μg mL-1 ( r2 = 0.9976-0.9991) for nerve agents. Limits of detection (S:N = 3:1) in the SIM mode were found in the range of 0.03-0.075 μg mL-1 for organophosphorus esters and 0.015-0.025 μg mL-1 for nerve agents. Limits of quantification (S:N = 10:1) were found in the range of 0.100-0.25 μg mL-1 for organophosphorus esters and 0.05-0.100 μg mL-1 for nerve agents in the SIM mode. The recoveries of the nerve agents and their markers ranged from 90.0 to 98.0% and 75.0 to 95.0% respectively. The repeatability and reproducibility (with relative standard deviations (RSDs) %) for organophosphorus esters were found in the range of 1.35-8.61% and 2.30-9.25% respectively. For nerve agents, the repeatability range from 1.00 to 7.75% and reproducibility were found in the range of 2.17-6.90%.
A newl type of fluorescent probe capable of detecting sulfur mustard (SM) simultant with concentration of 1.2 μM in solution and 0.5 ppm in gas phase has been developed. Owing to its molecular structure with thiocarbonyl component and two piperidyl moieties integrated into the xanthene molecular skeleton, this probe underwent a highly selective nucleophilic reaction with SM simultant and generated a thiopyronin derivative emitting intensive pink fluorescence. The distinct difference in electronic structure between the probe and thiopyronin derivative caused a marked shift of the absorbance band from 445 nm to 567 nm, which enabled an optimal wavelength propitious to excite the thiopyronin derivative but adverse to the probe. Such efficient separation of excitation wavelength and tremendous increase in fluorescence quantum yield from <0.002 to 0.53 upon conversion from the probe to thiopyronin derivative, jointly led to distinct contrast in the beaconing fluorescence signal (up to 850-fold) and therefore the unprecedented sensitivity for detecting SM simultant species.
The detection of DMMP (dimethyl methylphosphonate, a simulant of nerve agent sarin) was performed by using p-hexafluoroisopropanol phenyl (HFIPP) functionalized graphene (GR) via hydrogen bond interactions. For this, the HFIPP moiety was covalently functionalized on the surface of GR by a diazo reaction. The HFIPP-GR film-modified QCM electrodes were fabricated and their sensing characteristics towards DMMP were investigated. The proposed sensor showed good response towards sensing DMMP vapor at room temperature. In order to see the effect of HFIPP derivatives on DMMP vapor sensing, a comparative study was also conducted with unfunctionalized graphene. The sensitivity and detection limit of the HFIPP-GR sensor against DMMP vapors were 12.24 Hz ppm⁻¹ and 150 ppb respectively. The HFIPP-GR coated sensors showed good selectivity towards sensing DMMP vapors when compared with common organic vapors.
Since the first use of chemical warfare agents (CWA) (1915) to the recent attacks in Syria (2017) on mankind, there have been many incidents where CWA have claimed thousands of lives and left many more contaminated. In order to provide the appropriate and immediate medical counter measure to the victims, the exact classification of these chemical agents within few minutes on the field itself using a rapid and simple detection technique is extremely important to save the lives of the effected people. This has motivated all of us to explore the novel strategies/detection systems that can be field deployable with better selectivity and greater sensitivity. In view of this, we present a novel chemosensor, 3,6-bis(dimethylamino)-9(10H)-acridine thione (1), that can detect mustard gas and its simulant by both chromogenic and fluorogenic methods. For the first time, a single probe was able to demonstrate the detection with unprecedented selectivity over most probable interferences (nerve agents and alkylating agents) including solvents, acids, and bases which are routinely present in the environment. The desired level of sensitivity by naked eyes (0.04 mg/mL), UV spectroscopy (0.02 mg/mL), and fluorescence spectroscopy (0.005 mg/mL) makes this method truly field deployable. For the spot detection on the affected areas, a handy and potable chemosensor kit was also fabricated. This paper provides a simple, highly specific, and easy to use method in “actual sense” that not only detects the agents in the solution phase but also in the contaminated samples.
One of the major problems associated with the disposal of chemical weapons is that the agents have degraded over time, some quite seriously. Detecting and identifying the products of this decomposition are necessary prerequisites to the safe, complete and environmentally benign destruction of stockpiled weapons. The book presents and discusses both basic and novel techniques in a variety of areas of analytical chemistry which are relevant to achieving the ultimate destruction of chemical weapons. Presentations address sample collection and preparation, mass spectrometry, chromatographic techniques, NMR, and air monitoring techniques.
The work shows that analytical methods do exist to effectively support the destruction of chemical munitions. While further research is needed, the book provides an excellent baseline for further advances in the field.
The fundamental principles of Fourier transform mass spectrometry (FTMS) are presented. The motion of ions in a FTMS analyzer can be understood in terms of the magnetic and electric fields present in the FTMS analyzer cell. Ion motion is illustrated with the results of ion trajectory calculations under both collision-free conditions and at high pressure. Dipolar and quadrupolar excitation are described and compared. Practical considerations in obtaining ultra-high-mass resolution and accuracy are discussed. The FTMS experiment is a series of events (ionization excitation, detection) that occur in sequence. Pulse sequences for mass spectrometric and tandem mass spectrometric experiments are presented.
Positive and negative ion electrospray mass spectra were obtained directly from water/alcohol solutions for phosphoric acid, methylphosphonic acid and its mono( 1,2,2-trimethylpropyl) ester and bis(l-methylethyl) ester, Collisional activation and tandem mass spectrometry (MS/MS) of both the cations and anions of the phosphonates resulted in hydrogen rearrangement with loss of neutral alkenes to give the respective methylphosphonic acid anion (m/z 95) and methylphosphonic acid cation (m/z 97), Solutions of this series of compounds, which comprise a neutral, mono-basic, di-basic and tri-basic ligand, were complexed with alkali and alkali earth metal ions, The peaks observed in the positive ion electrospray mass spectra, and their propensity for fragmentation under collisional activation, were found to be consistent with the predicted stabilities of the complexes.
A new gas chromatographic detector for the determination of sulfur-containing compounds has recently become commercially available. The sulfur chemiluminescence detector (SCD) is based on forming sulfur monoxide in a reducing flame from sulfur-containing compounds being eluted from a gas chromatograph. The sulfur monoxide that is formed is subsequently detected by its chemiluminescent reaction with ozone. This new detector has been found to be at least one order of magnitude more sensitive than most flame photometric detectors. It produces a linear response, possesses a sulfur-to-carbon selectivity greater than 106, does not suffer appreciably from quenching, and has a response to various sulfur species that is nearly equimolar.
The fundamental principles of Fourier transform mass spectrometry (FTMS) are presented. The motion of ions in a FTMS analyzer can be understood in terms of the magnetic and electric fields present in the FTMS analyzer cell. Ion motion is illustrated with the results of ion trajectory calculations under both collision-free conditions and at high pressure. Dipolar and quadrupolar excitation are described and compared. Practical considerations in obtaining ultra-high-mass resolution and accuracy are discussed. The FTMS experiment is a series of events (ionization excitation, detection) that occur in sequence. Pulse sequences for mass spectrometric and tandem mass spectrometric experiments are presented.
A method for identification of some alkyl methylphosphonic acids in aqueous samples by liquid chromatography coupled to thermospray tandem mass spectrometry is described. The compounds are separated by reversed-phase liquid chromatography and identified by their daughter spectra after collision-induced dissociation of the quasi-molecular ions produced by the thermospray interface. The combination of liquid chromatographic separation of the acids with detection of the compoounds by tandem mass spectrometry gives enough information to identify the compounds. A twenty-to-fifty-times improvement in the signal-to-noise ratios, compared to normal thermospray detection, has been observed in these experiments.
Electrospray mass spectrometry has been used to detect and characterize the capsid proteins of a non-disrupted sample of cricket paralysis virus. By direct injection and by on-line liquid chromatography/mass spectrometry of the intact virus, three capsid proteins (VP1, VP2 and VP3) were detected and their relative molecular masses (RMM) accurately determined. In addition to these proteins, a fourth polypeptide (RMM=6012 Da) was detected which, by analogy with mammalian picornaviruses, may correspond to the capsid protein VP4. The finding of this latter protein now reduces the uncertainty of the classification of CrPV as a picornavirus.
A qualitative screening procedure was developed for the detection of the hydrolysis and related products of chemical warfare agents using liquid chromatography-mass spectrometry with atmospheric pressure chemical ionisation. A mixed C8/C18 reversed-phase column gave acceptable chromatography for the range of acidic, neutral and basic analytes. Detection limits for pure standards were less than 0.2 ng injected for the simple hydrolysis products of sulphur and nitrogen mustards, thiodiglycol sulphoxide, diisopropylaminoethanol and 3-quinuclidinol. Detection limits were in the range 0.2–8 ng injected for a series of alkylphosphonic acids and alkyl alkylphosphonic acids, and for benzilic acid. The methodology provides a rapid screening procedure for aqueous samples and extracts and was applied to the analysis of soil samples collected from bomb craters, and to spiked water and soil samples.
Under the provisions of the United Nations Chemical Weapons Convention (CWC), certain parts of chemical industry will be monitored to verify compliance with the Convention. This will include analysis of samples from industrial sites to check for the presence or absence of chemical warfare related compounds. One of the problems in screening the chemicals to be monitored under the CWC is that certain classes of chemical warfare agents are represented as families of chemicals, with many of the individual chemicals having no analytical data available. One example is the alkyl methylphosphonofluoridate family with an alkyl ester substituent from CH3 to C10H21. In this work, the mass spectra of 60 alkyl methylphosphonofluoridate family members have been studied to enable the development of rapid on-site screening methods for this family of chemicals.
The chemical warefare agents, sarin and soman, were detected and confirmed during full scanning capillary column ammonia chemical ionization mass spectrometry at nanogram levels in spiked extracts of a diesel exhaust environment sampled onto the charcoal of a Canadian C2 respirator canister. The selectivity of ammonia chemical ionization enabled the use of selected ion monitoring and resulted in detection limits of 40 pg and just above 500 pg for sarin and soman respectively in this extract. This diesel exhaust environment, typical of what might be encountered under battlefield conditions, was used to evaluate capillary column ammonia chemical ionization tandem mass spectrometry as a possible verification technology. Chemical interferences were reduced and significantly better detection limits, 15 pg and 80 pg for sarin and soman respectively, were obtained during gas chromatographic-tandem mass spectrometric analysis of these agents in the presence of numerous interfering diesel exhaust and charcoal bed components.
The chemical warfare agents sarin, soman and mustard were detected and confirmed during full-scanning gas chromatography (GC)—mass spectrometry (MS) at the nanogram level in spiked extracts of a diesel exhaust environment sampled onto the charcoal of a Canadian C2 respirator canister. This matrix, typical of what might be expected under battlefield conditions, was used for the development of a GCMSMS method for the verification of trace levels of sarin, soman and mustard. Chemical interferences associated with this complex sample were virtually eliminated and low-picogram GCMSMS detection limits were estimated for these chemical warfare agents in the presence of numerous interfering diesel exhaust and charcoal bed components.
Retention index monitoring using thermal desorption gas chromatographic analysis was developed as a method for the verification of compounds of chemical defense interest in environmental matrices. Gas chromatography retention indices were determined by loading solid adsorbent packed sampling tubes initially with the target compounds and subsequently wih a series of n-alkane probes. The resulting chromatographic performance and gas chromatography retention indices were shown to be independent of the tube loading method. A database of gas chromatography retention indices for chemical warfare agents and simulants was compiled and, in conjunction with simultaneous flame ionization and flame photometric detection, applied to the identification of triethyl phosphate, tributyl phosphate and diethyl malonate in water and soil samples.
The determination of thirteen organophosphorus acids, hydrolysis products of nerve agents and pesticides, by a combination of ion-pair liquid chromatography on a reversed-phase C18 column and thermospray mass spectrometry was investigated. Ammonium acetate and three tetraalkylammonium salts with different alkyl groups (methyl, ethyl and n-butyl) were applied as ion-pair reagents. All the organophosphorus acids could be eluted using water or water-methanol mixtures. Capacity factors (k′) were measured for some selected acids using water as eluent.The recorded thermospray mass spectra using ammonium acetate as electrolyte gave the [M + NH4]+ ion as a predominant peak, whereas with the tetraalkylammonium salts cluster ions were found. This difference in ionization mechanism was also reflected in the sensitivity. An amount of 100 pg of dimethylthiophosphoric acid could be detected by selected ion monitoring using ammonium acetate, whereas with tetramethylammonium hydroxide the amount was 5 ng. To obtain lower detection levels preconcentration could be achieved with a Sep-Pak C18 cartridge pretreated with a tetra-n-butylammonium salt.
Gas chromatographic detectors are increasingly used in order to obtain sensitive and selective detection in both conventional-size and miniaturized column liquid chromatography. A critical review of the literature on the use of thermionic, flame photometric and electron-capture detectors is presented, with emphasis on intrumental design, optimization of interfaces, and applications. Future trends are briefly discussed.
The ruggedness and analytical performance of on-line capillary gas chromatography-atomic emission detection (GC-AED) have been studied using 100-μl injections of sample solutions in ethyl acetate, via a loop-type interface. A series of organophosphorus compounds were selected as test analytes; they were monitored using the carbon, sulphur, nitrogen, chlorine, bromine and phosphorus channels. The system showed no flame-outs or other maintenance problems even after 300 large-volume injections. The analytical potential of the system, expressed in terms of repeatability, linearity and minimum detectable amount, was not affected and a 100-fold increase in analyte detectability, in terms of concentration units, compared with a conventional 1-μl injection was observed.As an application, GC-AED was combined off-line with solid-phase extraction. Several environmental contaminants were preconcentrated from river and tap water samples, and 20% (100 μl) of the ethyl acetate eluent were directly analysed. With a sample volume of only 10 ml, the detection limits of the organophosphorus pesticides typically were ca. 0.1 μg/l.
This chapter describes the analysis of marine toxins using liquid chromatography–mass spectrometry (LC–MS). The important task of monitoring seafood products for toxins presents significant challenges to the analytical chemist. Toxins range from polar, low-molecular-weight compounds to high-molecular-weight lipophilic substances. The electrospray and ion-spray ionization techniques have provided keys to the trace analysis of marine toxins through the combined techniques of LC–MS and capillary electrophoresis (CE)–MS. The generation of precise quantitative data, performance of multitoxin analyses, discovery of new toxins, analogs, and metabolites, and generation of structural information on new toxins are invaluable to toxin research. Although the equipment required is expensive, the possibility of performing automated, unattended analyses can justify such an investment if large numbers of samples are to be screened. In addition, the only MS ionization methods reported to be suitable for very polar, thermally labile compounds are fast atom bombardment (FAB), thermospray, electrospray, and ion spray.
High-performance liquid chromatography was carried out on a Techsil column (12.5 cm × 5 mm) with 8mM-H3PO4/acetonitrile (9:1) as mobile phase (1 ml/min) and detection at 1.45 V (vs. Ag/AgCl-satd. KCl) at an epoxy-carbon working electrode [cf. Henriques and Fogg, Analyst (London), 1984, 109, 1195]. The separation (in the order cited) of bis-(2-hydroxyethyl) sulfoxide, 2,2'-thiodiethanol, mercaptoacetic acid (I), 2,2'-dithiodiacetic acid, 1,4-thioxane, bis-(2-chloroethyl) sulfoxide (II), 3,9-dithia-6-oxaundecane-1,11-diol (retention time 8.4 min) and 1,4-dithiane (22.2 min) is illustrated; detection limits (ng) ranged from 0.5 for I to 100 for II. The separation (detection at 1.36 V) of cysteine, SS'-sulfonyldiethylenedicysteine, glutathione, methionine and SS'-thiodiethylenedicysteine (retention time 3.1 min) is also illustrated.
Wall-coated open tubular LC columns and packed capillary LC columns offer advantages in separation efficiency, solvent consumption, and injection/detection volumes compared to larger i.d. columns. They are readily interfaced to a variety of mass spectrometric techniques, including EI/CI, particle beam, CF-FAB, and ESI. The combined techniques are capable of handling small analyte volumes, and improved detection limits are often obtained. Significant advances in the application of MS in areas such as immunology have resulted from the use of capillary LC/MS. As these columns become more available commercially, the number of applications reported should increase dramatically. The development of high-sensitivity mass spectrometer ionization sources based on capillary LC columns is also noteworthy. This review spotlights the synergy that enhances the developments at the interface of these two techniques.
Temperature-programmed gas chromatographic retention indices, relative to n-alkane and n-alkylbis(trifluoromethyl)phosphine sulphide (M-standard) homologous series, were determined for nine chemical warfare agents using SE-54 fused-silica capillary columns. The influence of changes in the chromatographic conditions on the absolute values and on the reproducibility of the indices was evaluated. Nineteen parameters were investigated, with the purpose of discovering those most critical for the retention index monitoring of chemical warfare agents. The parameters most affecting the absolute value of the indices were the carrier gas flow-rate, the temperature programming rate and the properties of the column. Changes in conditions most strongly affected the indices of the low-volatility compounds O-ethyl S-2-(diisopropylamino)ethyl methylphosphonothioate (VX) and dibenz[b,f]-1,4-oxazepin (CR). The reproducibility of the indices was good in every case, even when the absolute values of the indices changed. Retention index monitoring is thus a reliable method for preliminary identification of compounds in mixtures, provided that the chromatographic system is regularly tested with a test mixture and corrections to the chromatographic conditions or the retention index library data are made where necessary.
The major sample components in dichloromethane extracts of munitions-grade tabun decontaminated with methanol-potassium hydroxide, inclding nine compounds not previously associated with tabun, were identified following capillary column gas chromatographic-mass spectrometric analysis. Electron impact fragmentation ions provided valuable structural information for the unknown sample components, but the presence of little or no molecular ion information for many of the components made identification difficult. Ammonia chemical ionization analysis was required to provide the complementary molecular ion information necessary for identification or tentative identification of these compounds. All the major sample components exhibited significant (M + H)+ and (M + NH4)+ pseudo-molecular ions and in some cases structurally significant chemical ionization fragmentation ions during capillary column ammonia chemical ionization gas chromatographic-mass spectrometric analysis.
Capillary column gas chromatography-ammonia and deuterated ammonia chemical ionization mass spectrometry was found to be a highly specific technique for the detection and identification of three long-chain sulfur vesicants, 2-chloroethyl (2-chloroethoxy)ethyl sulfide, sesquimustard and bis[(2-chloroethylthio)ethyl]ether. All three vesicants exhibited significant (M + NX4)+ (where X = H or H-2) pseudo-molecular ions and structurally significant chemical ionization fragmentation ions during capillary column gas chromatographic-ammonia chemical ionization mass spectrometric analysis. This method was utilized during analysis of contaminated painted panels circulated during the 3rd round robin verification exercise (1991). Chemical ionization data obtained during this exercise complemented the electron impact data obtained for sesquimustard and bis[(2-chloroethylthio)ethyl]ether and the specificity of the technique enabled the confirmation of 2-chloroethyl (2-chloroethoxy)ethyl sulfide, a compound masked by hydrocarbons in the painted panel extracts.
The technique of injecting liquid samples of volumes up to more than 100 μl is described. It relies on the reconcentration of the solute bands by well known mechanisms: the solvent effects for volatile sample components and the retention gap technique for higher boiling solutes. The involved technical parameters are discussed and recommendations given concerning selection of the retention gap, separation column, injection speed and chromatographic conditions.
The determination of mustard gas (2,2′-dichlorodiethyl sulphide) and some related vesicants in rubber and paint was investigated. The vesicants were isolated by extraction with methylene chloride or by dynamic headspace analysis at elevated temperatures. The latter procedure had the advantage that high-boiling additives did not interfere during the analysis by capillary column gas chromatography—mass spectrometry. The stability of the vesicants in the materials used proved to be good. No great losses were found after storage for weeks at room temperature.
Novel detectors are described for micro-column high-performance liquid chromatography; they are based on the well-known principles of flame photometric and thermionic detection. These devices exhibit good selectivity and sensitivity for organophosphorus compounds in both aqueous and selected organic solvents. The extremely small volume of these flame-based detectors and their enhanced response at low flow-rates make them particularly attractive for capillary-column high-performance liquid chromatography.
Two methods are presented for the derivatization of Adamsite [578-94-9]: bromination to give 2,2′,4,4′,6,6′-hexabromodiphenylamine [64524-09-0] (method A) and pyrolytic ethylation with dimethylformamide diethylacetal [1188-33-6] to give 10-ethyl-5,10-dihydrophenarsazine [53573-13-0] (method B). For the gas chromatographic analysis, atomic emission and mass spectrometric detection were applied. With regard to practicability and reliability, method proved to be superior to method A.
In comprehensive two-dimensional gas chromatography, the entire chromatogram eluting from the primary column is submitted to the secondary column for a second independent separation. The resulting two-dimensional chromatogram has peaks scattered about a plane rather than along a line. Peak capacity can be very large allowing much more complete separation of complex mixtures such as petroleum products. Moderately complex samples can be separated much more quickly than is possible with high-resolution one-dimensional gas chromatography. The method is a true hyphenated instrument analogous to gas chromatography-mass spectrometry.
The primary hydrolysate of the toxic military agent lewisite (2-chlorovinylarsonous acid, or CVA) can be determined in trace concentrations by gas chromatography, with flame-photometric detection after the CVA has been derivatized with 1,2-ethanedithiol to form a stable cyclic disulfide. The method has been shown to be applicable to the analysis of water samples that contain CVA in low ppb (109) concentrations. In addition, the method was demonstrated to be at least potentially useful for lewisite vapor determinations in air at sub-ppb levels in situations where any CVA found in the sample can be assumed to have been formed from lewisite. Relative to the other procedures that are available for determining lewisite or CVA, this procedure is more sensitive, more specific for the analyte or simpler to perform.
A sensitive method for post-column reaction detection of carbamate and organophosphorus pesticides is described, based on the inhibition of immobilized acetylcholinesterase. The compounds are separated by reversed-phase liquid chromatography with tetrahydrofuran—water as the mobile phase in a isocratic system. The reactor used for detection comprises a conventional flow injection assembly for monitoring activity of acetylcholinesterase immobilized on controlled pore glass in a mini-column with spectrophotometric detection. The detection limits and linear calibration ranges are 2.6 and 5–40 ng for paraoxon, 0.04 and 0.1–1.6 ng for diisopropylfluorophosphate, 18 and 20–100 ng for isopropyl N-phenyl-carbamate and 29 and 40–400 ng for isopropyl N-(3-chlorophenyl)carbamate. Only 16 min is required for the determination of a mixture of the above pesticides, and each enzyme column can be used for 90 determinations.
A reversed-phase high-performance liquid chromatography method for the detection and quantitation of sulfur mustard (HD) in water is described with detection at 200 nm. The detection based on the solubility of HD in water revealed that extremely low quantities of HD (4 to 5 mg/L) only are soluble. Experience shows that water is still the medium of choice for the analysis of HD in water and aqueous effluents in spite of the minor handicap of its half-life of ca. 4 minutes, which only calls for speedy analysis.
The detection and identification of decomposition products of chemical warfare agents can be used to investigate allegations of chemical warfare agent use, identify synthetic routes and trace sources of chemical warfare agents and their precursors. Compounds which contain a P-CH3 bond are particularly important as these compounds can provide evidence for the presence or decomposition of organo-phosphorus nerve agents. Capillary column GC-MS analysis of a distillation fraction of O-ethyl S-[2-diisopropylamino)ethyl] methylphosphonothiolate (VX), a major phosphonothiolate nerve agent, indicated the presence of two additional components comprising about 10% of the total volatile organic content. These compounds were characterized and identified by GC-MS, GC-MS/MS and 31P NMR as O,O-diethyl dimethylpyrophosphonate and O,O-diethyl dimethylmonothionopyrophosphonate. O,O-Diethyl dimethylmonothionopyrophosphonate presented a structural isomerism ambiguity whereby the position of the sulfur atom could not be defined by MS alone. Identification of the correct structure required spectrometric data from two different techniques, MS/MS and NMR, an important illustration of the use of complementary spectrometric techniques for unambiguous identification of chemicals for verification of the Chemical Weapons Convention.
A method for the stabilization and gas chromatographic analysis of the four stereoisomers of C(±)P(±)-1,2,2-trimethylpropyl methylphosphonofluoridate (C(±)P(±)-soman) in rat blood samples is described. Satisfactory stabilization of all four stereoisomers is obtained by (i) acidification of the blood sample to pH 4.2 at 0°C, to stabilize the C(±)P(+) isomers, (ii) addition of aluminum ions (2.5 mm) for complexation of fluoride ions, which prevents regeneration of C(±)P(−)-soman by free fluoride ions from soman-inhibited aliesterase, and (iii) addition of 2,2-dimethylpropyl methylphosphonofluoridate in order to occupy covalent binding sites for C(±)P(−)-soman. The stereoisomers of soman and internal standard are extracted from the blood-stabilizing buffer mixture with a Sep-Pak C18 cartridge and are subsequently eluted with ethyl acetate with overall extration recoveries of 52 ± 8%. The four soman stereoisomers are resolved and analyzed on a wide-bore capillary Chirasil Val column, synthesized, and coated in house, which also resolves the internal standard C(±)P(+)-1,2,2-[U-2H]trimethylpropyl methylphosphonofluoridate from C(±)P(±)-soman. Alternatively, the gas chromatographic analysis can be performed on a wide-bore capillary Chirasil Val column, identical with the commercially available Chirasil Val column, when combined in series with a Carbowax 20M column. This system resolves the four stereoisomers of soman and the internal standard C(−)P(+)-1,2,2-trimethylpropyl [U-2H]methylphosphonofluoridate. Using an alkali flame ionization detector, the detection limit of our procedure is ca. 250 pg soman isomer/blood sample.
Die Trennung der vier Stereoisomeren (C(-)PI2-), C(-)P(+),(C(+)P(-), C(+)P(+)) des Nervenreagenzes Soman (I) gelingt durch opplung der zur Trennung der Epimeren verwendeten Chirasil-Val-Säule (an L-Valin-tert.-butylamid gebundenes copolymeres Organosiloxan) mit einer kapillaren Säule, die mit der stationären Phase Carbowax 2OM ausgeschlagen ist.
A new interface based on an eluent jet in combination with a conventional gas chromatography momentum separator for use with electron impact mass spectrometry is described. The formation of the eluent jet is based on radio frequency inductive heating. The aerosol formation in the interface is discussed in relation to commercial particle beam (PB) interfaces. The interface is tested in combination with electron impact mass spectrometry using flow injection analysis at flow rates in the range of 5−15 μL/min commonly encountered in microcolumn liquid chromatography. Electron impact spectra at 1−10-ng levels are found to be comparable with reference spectra. In the single-ion mode, 50 pg of caffeine is detectable with a signal-to-noise ratio of 3:1. Contrary to many other PB systems, linear calibration plots are obtained in the tested range of 3−200 ng of caffeine.
The latest version of the thermospray LC/MS interface has been installed on a Biospect quadruple mass spectrometer. This interface requires only minor modification of the commercial instrument with a single mechanical vacuum pump required in addition to the pumping system normally used for CI operation. It appears that this LC interface can readily be adapted to other quadrupole mass spectrometers. LC effluents are thermosprayed directly into the ion source and the excess vapor pumped away by the added mechanical pump which is directly coupled to the ion source through a port opposite the electrically heated thermospray vaporizer. This system provides stable vaporization and ionization at flow rates up to 2 mL/min of aqueous mobile phase. When used with mobile phases containing significant concentration of ions in solution (ca. 10-4 to 1 M) no external ionizing source is required to achieve detection of many nonvolatile solutes at the subnanogram level. With weakly ionized mobile phases a conventional electron beam is used to provide gas-phase reagent ions for chemical ionization of solute molecules.
A new pulsed name photometer detector (PFPD) design is described with improved performance, Detection limits of 180 fg/s (sulfur), 7 fg/s (phosphorus), and 2 pg/s (nitrogen) are demonstrated when 2 rms noise is considered as the detection limit. The minimum detected amount of sulfur was further reduced with a sulfur doping method to about 30 fg/s, The factors affecting the selectivity are analyzed in terms of operating the PFPD as a specific detector without any hydrocarbon interferences, The effect of the pulsed nature of the PFPD on the chromatographic peak area and height reproducibility is modeled and analyzed, It is shown that above 3 Hz, the standard deviation of peak area is 2%, which is dominated by nondetector effects, The detector temperature effect was studied and is presented. The difference between light guide and lens optics is discussed. The column operation with hydrogen as a carrier gas is compared to that with helium, and the injection of chlorinated and fluorinated solvents is shown and discussed. New ways of obtaining additional information by using the added dimension of time are analyzed. It is shown how the simultaneous use of dual gates can provide unambiguous heteroatom identification, It is also described how a dual gate subtraction method results in a considerable enhancement of the interheteroatom selectivity, especially for phosphorus versus sulfur. The dual gate approach also provides up to an order of magnitude increase in the measurement dynamic range, Practical utilization of the PFPD is illustrated with the analysis of real-world samples, including thiophene in benzene, pesticides in a broccoli extract, and a sulfur-containing drug in human serum.
The separation of organic acids with extremely similar ion exchange retention characteristics is achieved using of solvent-compatible ion exchange columns. The required selectivity is obtained through the use of organic modifiers which produce a separation with both ion exchange and reversed-phase characteristics. This novel ion chromatographic approach has been applied to the separation of alkyl methylphosphonate degradation products of chemical warfare agents which have been previously inseparable using conventional ion exchange techniques. The method is suitable for routine environmental analysis of surface waters, groundwaters, and soils.
Retention data can be used to characterize and identify the components of a mixture. The identification power of a single column is rather limited, however. With several columns of different retention characteristics, a high identification power can be achieved. In order to apply chromatographic retention data for the identification of chemical species it is therefore important to select columns with low correlation of their retention characteristics. The retention behavior of five gas chromatographic columns was compared in pairs by linear regression of the retention data of a test set of compounds. The correlation coefficient of the two sets of retention data is an estimate of the degree of correlation of the columns. It was found that five pairs of columns had correlation coefficients of less than 0.900, the lowest value being 0.769. A more exact approach for the selection of columns for the chromatographic identification of compounds is based on the application of information theory. The information content of retention data (in bits) can be calculated from their probability distribution function. The information content was calculated for the same five gas chromatographic columns with the same retention data used in the calculation of the correlation coefficients. The optimal choice with respect to information power and effort is a combination of three columns having an information content of 19.8 bits. The loss of information caused by the correlation of the column retention amounts -2.7 bits in this case. The method of column selection was applied for the development of a gas chromatographic screening method for the identification of chemical warfare agents, precursors, and decomposition products. A test set of 16 chemically different species of such compounds was used.
The concept of a portable gas chromatography/ion mobility spectrometry (GC/IMS) device is introduced. The potential of the GC/IMS unit is investigated for the separation and characterization of vapor mixtures of various chemical classes. Parameters such as internal cell pressure, GC column flow rate, and column temperature were varied to determine the effects on speed and resolution for separating and charac-terizing mixtures. It was generally found that by reducing both the internal IMS cell pressure and the isothermal GC column temperature, the peak widths, retention times, and peak overlap could be varied for different classes of analytes. The GC/IMS system shows versatility in the various compound classes that can conveniently be analyzed by a hand-portable version. Mixtures included phosphonates, phosphates, alkyl ketones, and chlorophenols with total separation times in the 7-s to 2-min time range. Positive or negative ion polarities in IMS were used depending upon the functional group.
The determination of the paralytic shellfish poison saxitoxin by liquid chromatography/thermospray-mass spectrometry (LC/TS-MS) was investigated. It was found that a commercial sample contained an impurity, which was identified as the plasticizer tris(2-butoxyethyl) phosphate. Spraying of saxitoxin in acid solution at pH 2 led to a useful TS mass spectrum, containing some fragment ions in addition to the protonated molecule. Using pentafluoropropionic acid as a counter-ion, saxitoxin could be determined by LC/TS-MS on a C18 re versed-phase column. By injecting the relatively large volume of 1 mL, a concentration of 30 ng/mL could be measured.