Analytical methods based on liquid chromatography for the analysis of albumin adducts involved in retrospective biomonitoring of exposure to mustard agents

The objective of the present review is to list, describe, compare, and critically analyze the main procedures developed in the last 20 years for the analysis of digested alkylated peptides, resulting from the adduction of albumin by different mustard agents, and that can be used as biomarkers of exposure to these chemical agents. While many biomarkers of sulfur mustard, its analogues, and nitrogen mustards can easily be collected in urine such as their hydrolysis products, albumin adducts require blood or plasma collection to be analyzed. Nonetheless, albumin adducts offer a wider period of detectability in human exposed patients than urine found biomarkers with detection up to 25 days after exposure to the chemical agent. The detection of these digested alkylated peptides of adducted albumin constitutes unambiguous proof of exposure. However, their determination, especially when they are present at very low concentration levels, can be very difficult due to the complexity of the biological matrices. Therefore, numerous sample preparation procedures to extract albumin and to recover alkylated peptides after a digestion step using enzymes have been proposed prior to the analysis of the targeted peptides by liquid chromatography coupled to mass spectrometry method with or without derivatization step. This review describes and compares the numerous procedures including a number of different steps for the extraction and purification of adducted albumin and its digested peptides described in the literature to achieve detection limits for biological samples exposed to sulfur mustard, its analogues, and nitrogen mustards in the ng/mL range.

Colorimetric Gas Detection Tubes: Limits of Detection and Evaluation Using Active Chemical Warfare Agents

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.

Verification of exposure to chemical warfare agents through analysis of persistent biomarkers in plants

The continuing threats of military conflicts and terrorism may involve the misuse of chemical weapons. The present study aims to use environmental samples to find evidence of the release of such agents at an incident scene. A novel approach was developed for identifying protein adducts in plants. Basil (Ocimum basilicum), bay laurel leaf (Laurus nobilis) and stinging nettle (Urtica dioica) were exposed to 2.5 to 150 mg m^-3 sulfur mustard, 2.5 to 250 mg m^-3 sarin, and 0.5 to 25 g m^-3 chlorine gas. The vapors of the selected chemicals were generated under controlled conditions in a dedicated set-up. After sample preparation and digestion, the samples were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and liquid chromatography high resolution tandem mass spectrometry (LC-HRMS/MS), respectively. In the case of chlorine exposure, it was found that 3-chloro- and 3,5-dichlorotyrosine adducts were formed. As a result of sarin exposure, the o-isopropyl methylphosphonic acid adduct to tyrosine could be analyzed, and after sulfur mustard exposure the N1- and N3-HETE-histidine adducts were identified. The lowest vapor exposure levels for which these plant adducts could be detected, were 2.5 mg m^-3 for sarin, 50 mg m^-3 for chlorine and 12.5 mg m^-3 for sulfur mustard. Additionally, protein adducts following a liquid exposure of only 2 nmol Novichock A-234, 0.4 nmol sarin and 0.2 nmol sulfur mustard could still be observed. For both vapor and liquid exposure, the amount of adduct formed increased with the level of exposure. In all cases synthetic reference standards were used for unambiguous identification. The window of opportunity for investigation of agent exposure through the analysis of plant material was found to be remarkably long. Even three months after the actual exposure, the biomarkers could still be detected in the living plants, as well as in dried leaves. An important benefit of the current method is that a relatively simple and generic sample work-up procedure can be applied for all agents studied. In conclusion, the presented work clearly demonstrates the possibility of analyzing chemical warfare agent biomarkers in plants, which is useful for forensic reconstructions, including the investigation into alleged use in conflict areas.

Decontamination of mustard sulfur and VX by sodium percarbonate complexed with 1-acetylguanidine as a novel activator

The peroxide-based decontaminants had attracted great attention for degradation of chemical warfare agents (CWAs) because of their high performance, non-corrosive and environmental-friendly merits. Hydrogen peroxide can be activated by some organic activators to enhance the oxidation ability. In this work, a novel formula based on sodium percarbonate (SPC) complexed with 1-acetylguanidine (ACG) was investigated for decontamination of sulfur mustard (HD) and VX as CWAs. In the experimental results, the active species acetyl peroxide imide acid in the formula aqueous solution was detected in situ by Raman and ¹³C NMR spectroscopy. The optimized conditions of the decontamination formula (SPC/ACG) were suggested that, the molar ratio of active oxygen and activator ([O]/[ACG]) was 1:1 while the pH value of the formula aqueous solution was about 9. To achieve the decontamination percentage over 99%, the molar ratio of active oxygen to CWA ((O)/(CWA)) needed to be at least 3 for HD and 7 for VX. Meanwhile, the degradation products detected by gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS) and ion chromatography (IC) indicated that the oxidation and elimination reactions should have occurred on HD molecule, while the degradation of VX mainly originate from the nucleophilic substitution and oxidation reactions.

Ultrafine Silver Nanoparticle Encapsulated Porous Molecular Traps for Discriminative Photoelectrochemical Detection of Mustard Gas Simulants by Synergistic Size-Exclusion and Site-Specific Recognition

The rapid, discriminative, and portable detection of highly toxic chemical warfare agents is extremely important for response to public security emergencies but remains a challenge. One plausible solution involves the integration of porous molecular traps onto a photoelectrochemical (PEC) sensor. Here, a fast and facile protocol is developed to fabricate sub-1 nm AgNPs encapsulated hydrogen-bonded organic framework (HOF) nanocomposite materials through an in situ photoreduction and subsequent encapsulation process. Compared to traditional semiconductors and selected metal-organic frameworks (MOF) materials, these AgNPs@HOFs show significantly enhanced photocurrent. Most importantly, the portable PEC device based on AgNPs@HOF-101 can selectively recognize 13 different mustard gas simulants, including 2-chloroethyl ethyl sulfide (CEES), based on synergistic size-exclusion and specific recognition. The extremely low detection limit for CEES (15.8 nmol L^-1 ), reusability (at least 30 cycles), and long-term working stability (at least 30 d) of the portable PEC device warrant its use as a chemical warfare agents (CWAs) sensor in practical field settings. More broadly, this work indicates that integrating porous molecular traps onto PEC sensors offers a promising strategy to further develop portable devices for CWAs detection with both ultrahigh sensitivity and selectivity.

A proteomics strategy for the identification of multiple sites in sulfur mustard-modified HSA and screening potential biomarkers for retrospective analysis of exposed human plasma

A major challenge for the unequivocal verification of alleged exposure to sulfur mustard (HD) lies in identifying its multiple modifications on endogenous proteins and utilizing these modified proteins to achieve accurate, sensitive, and rapid detection for retrospective analysis of HD exposure. As the most abundant protein in human plasma, human serum albumin (HSA) can react with many xenobiotics, such as HD, to protect the body from damage. The HSA adducts induced by HD have been used as biomarkers for the verification of HD exposure. In this study, the modification sites on HSA by HD were identified through application of the bottom-up strategy used in proteomics, and 41 modified sites were discovered with seven types of amino acids, of which 3 types were not previously reported. Then, different enzymes, including pepsin, endoproteinase Glu-C, and pronase, were applied to digest HD-HSA to produce adducts with hydroxyethylthioethyl (HETE) groups, which may be used as potential biomarkers for HD exposure. As candidates for retrospective analysis, sixteen adducts were obtained and characterized with ultra-high-pressure liquid chromatography coupled with quadrupole-Orbitrap mass spectrometry (UHPLC-QE Focus MS). These potential biomarkers were evaluated in human plasma that was exposed in vitro to HD and five of its analogues. This study integrated the identification of modification sites through application of the bottom-up strategy of proteomics and screening biomarkers, providing a novel strategy for retrospective detection of the exposure of xenobiotic chemicals.

Investigation of long-term hazards of chemical weapon agents in the environment of Sardasht area, Iran

The present study aimed to investigate the persistence and existence of chemical warfare agents (CWAs) and related dissipation products in the environment of Sardasht area, Iran. Three types of environmental samples including water, soil, and native local plant materials were collected and analyzed. Gas chromatography-mass spectrometry in the electron impact ionization mode has been developed for the separation, screening, identification, and qualification of chemicals after the sample preparation methods. The initial results revealed that no trace of related compounds or CWAs was detected in the soil and water samples. However, trace amounts of some degradation products of blistering agents like mustard gas (HD) and lewisite were found in a tree wood from a house subjected to chemical attack as well as in barley samples (a mixture of leaves and root) collected from an agricultural field in the area indicating chronic low exposure to the environment and people. In order to validate the applied extraction procedures, ethylene glycol was spiked to some of the samples including groundwater, surface soil, grape, and alfalfa plants. All the recoveries were in the range of 83.6-107.4% with the relative standard deviations varying from 4.9% to 12.4% (n = 3) successfully.

Ultrasensitive detection of trace chemical warfare agent-related compounds by thermal desorption associative ionization time-of-flight mass spectrometry

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.

Sensitive and selective detections of mustard gas and its analogues by 4-mercaptocoumarins as fluorescent chemosensors in both solutions and gas phase

Mustard gas has been used as a chemical warfare agent for a century, and is the most likely chemical weapon used in wars or by terrorists. Thus, it is important to develop a facile, rapid and highly selective method for the detection of mustard gas. In this paper, two fluorescent probe molecules, 4-mercaptocoumarins, have been developed for rapid and sensitive detections of SM and its analogues (CEES and NH1) in both solutions and gas phase. The sensing reaction is a nucleophilic addition at three-membered hetercyclic sulfonium/ammonium formed from SM, CEES/NH1 in ethanol. Two fluorescent probes (4-mercaptocoumarins, ArSH) in ethanol deprotonate to form thiophenol anions (ArS^-) resulting from their low pKa values (3.2-3.4), and the nucleophilic addition of the anion ArS^- generates the corresponding thioethers, giving a turn-on fluorescence response. The thiophenol anion can fast sense SM, CEES and NH1 (within 1-4 min) with high sensitivity (~nM level) at 60 °C, and high selectivity through adding a tertiary amine, and two probes exhibit excellent chemical and photostability in detection systems. Furthermore, a facile test strip with the sensor was fabricated for the detection of CEES vapor with rapid response (3 min), high sensitivity (9 ppb) and high selectivity.

Identification and toxicological evaluation of cyclic sulfonium ion degradation products of sulphur mustard

In the aftermath of WWII large amount seized German chemical munitions were dumped in the Baltic Sea by Allied forces. In this work, we have compared the chemical content of the solidified blocks of dumped WWII mustard gas collected from the Baltic Sea with solid precipitate from stored mustard gas, known as heel. We have identified the same cyclic sulfonium ions in both samples. In assessing the environmental and toxicological impact of dumped sulphur mustard munitions on the world's oceans the potential risk posed by cyclic sulphur mustard salts have so far not been incorporated. The toxicity of 1-(2-chloroethyl)-1,4-dithiane and its hydrolysis product 1-(2-hydroxyethyl)- 1,4-dithiane was evaluated using three different cell lines. Their effect on released pro-inflammatory cytokines was also measured. The toxicity tests showed low toxicity and low pro-inflammatory response and we therefore conclude that the environmental threat posed by these compounds is low.

Acute aquatic toxicity of sulfur mustard and its degradation products to Daphnia magna

Sulphur mustard (HD) was the most widely produced chemical warfare agent (CWA) in the history of chemical warfare (CW). Simultaneously, the loads of HD account as by far the largest fraction of the sea-dumped CW. Nowadays its presence in the marine ecosystems recognized as a serious threat for marine users and maritime industries. Although, during over a decade of research much has been done to assess the environmental threats linked with underwater chemical munitions. There are, however, essential gaps in scientific knowledge including scarce information about the aquatic toxicity thresholds of HD and its degradation products. Standardized biotests were performed according to the Organisation for Economic Co-operation and Development (OECD) Test No. 202: Daphnia sp. Acute Immobilisation Test guidelines. Obtained results provide a solid foundation for comparison and categorisation of threats of HD and its degradation products. With the D. magna LC₅₀ aquatic acute toxicity threshold at as low as 224 ± 12 μg × L^-1, 1,2,5-trithiepane is very toxic, being one of the most toxic CWA degradation products that have been investigated up to date. It exhibits stronger effects than 1,4,5-oxadithiepane and diluted HD that turn out to be toxic. In total, the toxicity of 7 compounds has been estimated. Whenever possible, toxicity thresholds were compared with previously existing data originating from different biotests and mathematical modelling.

Evaluation of carbon aerogel-based solid-phase extraction sorbent for the analysis of sulfur mustard degradation products in environmental water samples

In this study, SPE method using a carbon aerogel(CA)-based sorbent was developed and evaluated for the simultaneous extraction of sulfur mustard (HD) degradation products from environmental water samples. Applied CAs proved to be very promising materials for use as SPE sorbents, due to their high porosity, very low density and a large specific surface area. 10 degradation products of HD, both aliphatic and cyclic (thiodiglycol (TDG), TDG sulfoxide, TDG sulfone, 3,5-dithia-1,7-heptanediol, 3,6-dithia-1,8-octanediol, 1,4-thioxane, 1,3-dithiolane, 1,4-dithiane, 1,2,5-trithiepane, and 1,4,5-oxadithiepane) were extracted on a CA-based SPE cartridge. The concentrations of target analytes in the eluate were determined by HPLC-DAD and CE-DAD. Several parameters affecting the extraction efficiency, including the kind and volume of the eluting solvent, sample loading flow rate, volume and ionic strength as well as the reusability of the cartridge, were investigated and optimized to achieve the best performance for the analytes. A series of quantitative parameters such as linear range, coefficient of determination, LOD, LOQ and precision were examined under the optimized conditions. High sensitivity (LODs 0.17-0.50 μM) and high precision (intraday RSD = 2.0-7.7% and interday RSD = 2.7-9.9%) for all the analytes were achieved. The performance of the CA-based sorbent was compared with that of commonly used SPE sorbents. Applied for the analysis of spiked pore water samples collected from the Bornholm Basin, one of the largest chemical warfare dumping sites in the Baltic Sea, the proposed method allowed high SPE recoveries of all the analytes ranging from 83.5 to 99.7% to be obtained.

Environmental exposure to organophosphorus nerve agents

Exposure to organophosphorus nerve agents, the most deadly chemical warfare agents, is possible in a variety of situations, such as destruction of chemical warfare agents, terrorist attacks, armed conflicts or accidents in research laboratories and storage facilities. Hundreds of thousands of tons of chemical munitions were disposed of at the sea in the post World War II period, with European, Russian, Japanese and US coasts being the most affected. Sulfur mustard, Lewisite and nerve agents appear to be the most frequently chemical warfare agents disposed of at the sea. Addressing the overall environmental risk, it has been one of the priorities of the world community since that time. Aside from confirming exposure to nerve agents in the alleged use for forensic purposes, the detection and identification of biological markers of exposure are also needed for the diagnosis and treatment of poisoning, in addition to occupational health monitoring for specific profiles of workers. When estimating detrimental effects of acute or potential chronic sub-lethal doses of organophosphorus nerve agents, released accidentally or intentionally into the environment, it is necessary to understand the wide spectra of physical, chemical and toxicological properties of these agents, and predict their ultimate fate in environmental systems.

Behavior of sulfur mustard in sand, concrete, and asphalt matrices: Evaporation, degradation, and decontamination

The evaporation, degradation, and decontamination of sulfur mustard on environmental matrices including sand, concrete, and asphalt are described. A specially designed wind tunnel and thermal desorber in combination with gas chromatograph (GC) produced profiles of vapor concentration obtained from samples of the chemical agent deposited as a drop on the surfaces of the matrices. The matrices were exposed to the chemical agent at room temperature, and the degradation reactions were monitored and characterized. A vapor emission test was also performed after a decontamination process. The results showed that on sand, the drop of agent spread laterally while evaporating. On concrete, the drop of the agent was absorbed immediately into the matrix while spreading and evaporating. However, the asphalt surface conserved the agent and slowly released parts of the agent over an extended period of time. The degradation reactions of the agent followed pseudo first order behavior on the matrices. Trace amounts of the residual agent present at the surface were also released as vapor after decontamination, posing a threat to the exposed individual and environment.

Evaluation of Molecular Markers and Analytical Methods Documenting the Occurrence of Mustard Gas and Arsenical Warfare Agents in Soil

The chemicals warfare agents (CWAs) are an extremely toxic class of molecules widely produced in many industrialized countries for decades, these compounds frequently contained arsenic. The plants where the CWAs have been produced or the plants where they have been demilitarized after the Second World War with unacceptable techniques can represent a serious environmental problem. CWAs standards are difficult to find on market so in present work an environmental assessment method based on markers has been proposed. Triphenylarsine, phenylarsine oxide and thiodiglycol have been selected as markers. Three reliable analytical methods based on gaschromatography and mass detection have been proposed and tested for quantitative analysis of markers. Methods performance have been evaluated testing uncertainty, linearity, recovery and detection limits and also comparing detection limits with exposure limits of reference CWAs. Proposed assessment methods have been applied to a case study of a former industrial plant sited in an area characterized by a high background of mineral arsenic.

Efficacy of scalp hair decontamination following exposure to vapours of sulphur mustard simulants 2-chloroethyl ethyl sulphide and methyl salicylate

Chemical warfare agents are an actual threat and victims' decontamination is a main concern when mass exposure occurs. Skin decontamination with current protocols has been widely documented, as well as surface decontamination. However, considering hair ability to trap chemicals in vapour phase, we investigated hair decontamination after exposure to sulphur mustard simulants methyl salicylate and 2-chloroethyl ethyl sulphide. Four decontamination protocols were tested on hair, combining showering and emergency decontamination (use of Fuller's earth or Reactive Skin Decontamination Lotion RSDL^®). Both simulants were recovered from hair after treatment, but contents were significantly reduced (42-85% content allowance). Showering alone was the least efficient protocol. Concerning 2-chloroethyl ethyl sulphide, protocols did not display significant differences in decontamination efficacy. For MeS, use of emergency decontaminants significantly increased showering efficacy (10-20% rise), underlining their usefulness before thorough decontamination. Our results highlighted the need to extensively decontaminate hair after chemical exposure. Residual amounts after decontamination are challenging, as their release from hair could lead to health issues.

Evaluation of the efficacy of a portable LIBS system for detection of CWA on surfaces

Laser-induced breakdown spectroscopy (LIBS) is a laser-based optical technique particularly suited for in situ surface analysis. A portable LIBS instrument was tested to detect surface chemical contamination by chemical warfare agents (CWAs). Test of detection of surface contamination was carried out in a toxlab facility with four CWAs, sarin (GB), lewisite (L1), mustard gas (HD), and VX, which were deposited on different substrates, wood, concrete, military green paint, gloves, and ceramic. The CWAs were detected by means of the detection of atomic markers (As, P, F, Cl, and S). The LIBS instrument can give a direct response in terms of detection thanks to an integrated interface for non-expert users or so called end-users. We have evaluated the capability of automatic detection of the selected CWAs. The sensitivity of our portable LIBS instrument was confirmed for the detection of a CWA at surface concentrations above 15 μg/cm(2). The simultaneous detection of two markers may lead to a decrease of the number of false positive.

The chemiluminescence determination of 2-chloroethyl ethyl sulfide using luminol-AgNO3-silver nanoparticles system

A highly sensitive chemiluminescence (CL) method for the determination of 2-chloroethyl ethyl sulfide (2-CEES) was presented. It was found that 2-chloroethyl ethyl sulfide (2-CEES) could inhibit the CL of the luminol-AgNO3 system in the presence of silver nanoparticles in alkaline solution, which made it applicable for determination of 2-CEES. The presented method is simple, convenient, rapid and sensitive. Under the optimized conditions, the calibration curve was linear in the range of 0.0001-1ngmL(-1), with the correlation coefficient of 0.992; while the limit of detection (LOD), based on signal-to-noise ratio (S/N) of 3, was 6×10(-6)ngmL(-1). Also, the relative standard deviation (RSD, n=5) for determination of 2-CEES (0.50ngmL(-1)) was 3.1%. The method was successfully applied for the determination of 2-CEES in environmental aqueous samples.

Decontamination of adsorbed chemical warfare agents on activated carbon using hydrogen peroxide solutions

Mild treatment with hydrogen peroxide solutions (3-30%) efficiently decomposes adsorbed chemical warfare agents (CWAs) on microporous activated carbons used in protective garments and air filters. Better than 95% decomposition of adsorbed sulfur mustard (HD), sarin, and VX was achieved at ambient temperatures within 1-24 h, depending on the H2O2 concentration. HD was oxidized to the nontoxic HD-sulfoxide. The nerve agents were perhydrolyzed to the respective nontoxic methylphosphonic acids. The relative rapidity of the oxidation and perhydrolysis under these conditions is attributed to the microenvironment of the micropores. Apparently, the reactions are favored due to basic sites on the carbon surface. Our findings suggest a potential environmentally friendly route for decontamination of adsorbed CWAs, using H2O2 without the need of cosolvents or activators.

Physics-based agent to simulant correlations for vapor phase mass transport

Chemical warfare agent simulants are often used as an agent surrogate to perform environmental testing, mitigating exposure hazards. This work specifically addresses the assessment of downwind agent vapor concentration resulting from an evaporating simulant droplet. A previously developed methodology was used to estimate the mass diffusivities of the chemical warfare agent simulants methyl salicylate, 2-chloroethyl ethyl sulfide, di-ethyl malonate, and chloroethyl phenyl sulfide. Along with the diffusivity of the chemical warfare agent bis(2-chloroethyl) sulfide, the simulant diffusivities were used in an advection-diffusion model to predict the vapor concentrations downwind from an evaporating droplet of each chemical at various wind velocities and temperatures. The results demonstrate that the simulant-to-agent concentration ratio and the corresponding vapor pressure ratio are equivalent under certain conditions. Specifically, the relationship is valid within ranges of measurement locations relative to the evaporating droplet and observation times. The valid ranges depend on the relative transport properties of the agent and simulant, and whether vapor transport is diffusion or advection dominant.

Development of portable mass spectrometer with electron cyclotron resonance ion source for detection of chemical warfare agents in air

A portable mass spectrometer with an electron cyclotron resonance ion source (miniECRIS-MS) was developed. It was used for in situ monitoring of trace amounts of chemical warfare agents (CWAs) in atmospheric air. Instrumental construction and parameters were optimized to realize a fast response, high sensitivity, and a small body size. Three types of CWAs, i.e., phosgene, mustard gas, and hydrogen cyanide were examined to check if the mass spectrometer was able to detect characteristic elements and atomic groups. From the results, it was found that CWAs were effectively ionized in the miniECRIS-MS, and their specific signals could be discerned over the background signals of air. In phosgene, the signals of the 35Cl+ and 37Cl+ ions were clearly observed with high dose-response relationships in the parts-per-billion level, which could lead to the quantitative on-site analysis of CWAs. A parts-per-million level of mustard gas, which was far lower than its lethal dosage (LCt50), was successfully detected with a high signal-stability of the plasma ion source. It was also found that the chemical forms of CWAs ionized in the plasma, i.e., monoatomic ions, fragment ions, and molecular ions, could be detected, thereby enabling the effective identification of the target CWAs. Despite the disadvantages associated with miniaturization, the overall performance (sensitivity and response time) of the miniECRIS-MS in detecting CWAs exceeded those of sector-type ECRIS-MS, showing its potential for on-site detection in the future.

Using metal complex ion-molecule reactions in a miniature rectilinear ion trap mass spectrometer to detect chemical warfare agents

The gas-phase reactions of a series of coordinatively unsaturated [Ni(L)n](y+) complexes, where L is a nitrogen-containing ligand, with chemical warfare agent (CWA) simulants in a miniature rectilinear ion trap mass spectrometer were investigated as part of a new approach to detect CWAs. Results show that upon entering the vacuum system via a poly(dimethylsiloxane) (PDMS) membrane introduction, low concentrations of several CWA simulants, including dipropyl sulfide (simulant for mustard gas), acetonitrile (simulant for the nerve agent tabun), and diethyl phosphite (simulant for nerve agents sarin, soman, tabun, and VX), can react with metal complex ions generated by electrospray ionization (ESI), thereby providing a sensitive means of detecting these compounds. The [Ni(L)n](2+) complexes are found to be particularly reactive with the simulants of mustard gas and tabun, allowing their detection at low parts-per-billion (ppb) levels. These detection limits are well below reported exposure limits for these CWAs, which indicates the applicability of this new approach, and are about two orders of magnitude lower than electron ionization detection limits on the same mass spectrometer. The use of coordinatively unsaturated metal complexes as reagent ions offers the possibility of further tuning the ion-molecule chemistry so that desired compounds can be detected selectively or at even lower concentrations.

Desorption of bis(2-chloroethyl) sulfide, mustard agent, from the surface of hardened cement paste (HCP) wafers

The decontamination of surfaces exposed to chemical warfare agents is an interesting scientific topic. The desorption behavior of bis(2-chloroethyl) sulfide (sulfur mustard, HD) from the surface of the HD-contaminated hardened cement paste (HCP) was investigated under different weather conditions, which should provide scientific reference data for protection and decontamination projects involving HD-contaminated HCP in different conditions. The desorption of HD from the surface of HCP wafers was studied, and the effects of the purge air flow rate, water content, sorption temperature, and substrate age were investigated. HD desorption was detected from the surface of HD-contaminated HCP, but the desorption velocity was relatively slow. The desorption quantity remained within an order of magnitude throughout a time span of 36h (25°C at 200mL/min of purge air), and the amount of HD that was desorbed from each square meter of HCP surface was approximately 1.1g (25°C at 200mL/min of purge air), which was approximately 5.5 percent of the total HD that was initially applied. A higher flow rate of the purge air, increased water content, and longer substrate age of HCP all increased the HD desorption. In contrast, increased temperatures suppressed HD desorption.

Study on evaporation characteristics of a sessile drop of sulfur mustard on glass

The evaporation characteristics (evaporation rates and process) of a sessile drop of sulfur mustard on glass has been studied using a laboratory-sized wind tunnel, gas chromatograph mass spectrometry, and drop shape analysis. It showed that the evaporation rates of the droplet increased with temperature and air flow. The effect of temperature on the rates was more pronounced at lower air flow. Air flow was less effective at lower temperature. The contact angle of the droplet was initially observed as θ = 19.5° ± 0.7 and decreased linearly with time until it switched to a constant mode.

Sulphur mustard degradation on zirconium doped Ti-Fe oxides

Zirconium doped mixed nanodispersive oxides of Ti and Fe were prepared by homogeneous hydrolysis of sulphate salts with urea in aqueous solutions. Synthesized nanodispersive metal oxide hydroxides were characterised as the Brunauer-Emmett-Teller (BET) surface area and Barrett-Joiner-Halenda porosity (BJH), X-ray diffraction (XRD), infrared (IR) spectroscopy, scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) microanalysis, and acid-base titration. These oxides were taken for an experimental evaluation of their reactivity with sulphur mustard (chemical warfare agent HD or bis(2-chloroethyl)sulphide). The presence of Zr(4+) dopant tends to increase both the surface area and the surface hydroxylation of the resulting doped oxides in such a manner that it can contribute to enabling the substrate adsorption at the oxide surface and thus accelerate the rate of degradation of warfare agents. The addition of Zr(4+) to the hydrolysis of ferric sulphate with urea shifts the reaction route and promotes formation of goethite at the expense of ferrihydrite. We discovered that Zr(4+) doped oxo-hydroxides of Ti and Fe exhibit a higher degradation activity towards sulphur mustard than any other yet reported reactive sorbents. The reaction rate constant of the slower parallel reaction of the most efficient reactive sorbents is increased with the increasing amount of surface base sites.

Facility monitoring of chemical warfare agent simulants in air using an automated, field-deployable, miniature mass spectrometer

Vapors of four chemical warfare agent (CWA) stimulants, 2-chloroethyl ethyl sulfide (CEES), diethyl malonate (DEM), dimethyl methylphosphonate (DMMP), and methyl salicylate (MeS), were detected, identified, and quantitated using a fully automated, field-deployable, miniature mass spectrometer. Samples were ionized using a glow discharge electron ionization (GDEI) source, and ions were mass analyzed with a cylindrical ion trap (CIT) mass analyzer. A dual-tube thermal desorption system was used to trap compounds on 50:50 Tenax TA/Carboxen 569 sorbent before their thermal release. The sample concentrations ranged from low parts per billion [ppb] to two parts per million [ppm]. Limits of detection (LODs) ranged from 0.26 to 5.0 ppb. Receiver operating characteristic (ROC) curves are presented for each analyte. A sample of CEES at low ppb concentration was combined separately with two interferents, bleach (saturated vapor) and diesel fuel exhaust (1%), as a way to explore the capability of detecting the simulant in an environmental matrix. Also investigated was a mixture of the four CWA simulants (at concentrations in air ranging from 270 to 380 ppb). Tandem mass (MS/MS) spectral data were used to identify and quantify the individual components.

Long-term evaluation of the fate of sulfur mustard on dry and humid soils, asphalt, and concrete

The long-term fate of the blister agent sulfur mustard (HD, bis(2-chloroethyl)sulfide) was determined in a variety of commercial and natural matrices. HD was found to be extremely stable in dry matrices for over a year. The addition of 5% water to the matrices induced slow degradation of HD, which lasted several months. The major degradation product in sands and asphalt was found to be a sulfonium salt, S[CH(2)CH(2)S(+)(CH(2)CH(2)OH)(2)](2) (H-2TG). Red loam soil, which has not been examined before, exhibited strong interaction with HD, both in dry form and in the presence of water. Humid red loam soil gave rise to unique oxidative degradation products. On humid concrete HD degraded to a complex mixture of products, including vinyls. This may be attributed to the basic sites incorporated in concrete.

Uptake, tissue distribution, and excretion of 14C-sulfur mustard vapor following inhalation in F344 rats and cutaneous exposure in hairless guinea pigs

Sulfur mustard (SM), a vessicating agent, has been used in chemical warfare since 1918. The purpose of this study was to quantitate SM vapor deposition, tissue distribution, and excretion following intratracheal inhalation in rats and cutaneous exposure in guinea pigs. 14C-SM vapors for inhalation studies were generated by metering liquid 14C-SM into a heated J tube. Vapors were transported via carrier air supplemented with oxygen and isoflurane to an exposure plenum. Anesthetized rats with transorally placed tracheal catheters were connected to the plenum port via the catheter hub for exposure (approximately 250 mg 14C-SM vapor/m(3); 10 min). For dermal exposure, 3 Teflon cups (6.6 cm(2) exposure area per cup) were applied to the backs of each animal and vapors (525 mg 14C-SM/m(3); 12 min) were generated by applying 6 μl 14C-SM to filter paper within each cup. Animals were euthanized at selected times up to 7 d postexposure. SM equivalents deposited in rats and guinea pigs were 18.1 ± 3 μg and 29.8 ± 5.31 μg, respectively. Inhaled SM equivalents rapidly distributed throughout the body within 2 h postexposure, with the majority (>70%) of material at that time located in carcass and pelt. In guinea pigs, >90% of deposited SM equivalents remained in skin, with minor distribution to blood and kidneys. Urine was the primary route of excretion for both species. Results indicate inhaled SM is rapidly absorbed from the lung and distributed throughout the body while there is limited systemic distribution following cutaneous exposure.

Rapid monitoring of sulfur mustard degradation in solution by headspace solid-phase microextraction sampling and gas chromatography mass spectrometry

A method using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography/mass spectrometry (GC/MS) analysis has been developed to gain insight into the degradation of the chemical warfare agent sulfur mustard in solution. Specifically, the described approach simplifies the sample preparation for GC/MS analysis to provide a rapid determination of changes in sulfur mustard abundance. These results were found to be consistent with those obtained using liquid-liquid extraction (LLE) GC/MS. The utility of the described approach was further demonstrated by the investigation of the degradation process in a complex matrix with surfactant added to assist solvation of sulfur mustard. A more rapid reduction in sulfur mustard abundance was observed using the HS-SPME approach with surfactant present and was similar to results from LLE experiments. Significantly, this study demonstrates that HS-SPME can simplify the sample preparation for GC/MS analysis to monitor changes in sulfur mustard abundance in solution more rapidly, and with less solvent and reagent usage than LLE.

Efficient heterogeneous and environmentally friendly degradation of nerve agents on a tungsten-based POM

Common (chemical warfare agent) CWA decontaminants exhibit harsh and corrosive characteristics, and are harmful to the environment. In the course of our quest for active sorbents as efficient decontaminants, Keggin-type polyoxometalate (POM) (NH(4))(3)PW(12)O(40) was tested for oxidative degradation of CWAs. Although oxidation did not take place, sarin (GB) and VX were smoothly decontaminated to non-toxic products within 1 and 10 days, respectively. Degradation was carried out directly on the powder, eliminating the need for solvents. Mustard gas (HD), whose degradation is highly dependent on oxidation, was not decontaminated by this POM. Solid state MAS NMR ((31)P and (13)C) was utilized both for POM characterization and for decontamination studies monitoring.

Microbial responses to mustard gas dumped in the Baltic Sea

Microbiological studies were carried out on chemical weapon dump sites in the Baltic Sea. The effect of mustard gas hydrolysis products (MGHPs) on marine microbiota and the ability of microorganisms to degrade MGHPs were studied. Many stations at the dump sites demonstrated reduced microbial diversity, and increased growth of species able to use mustard gas hydrolysis products as sole source of carbon. Significant amounts of MGHP-degrading bacteria were revealed in the near-bottom water. The MGHP-degrading microorganisms identified as Achromobacter sp., Pseudomonas sp., and Arthrobacter sp. were isolated. These microorganisms were capable of utilizing the major product of hydrolysis, thiodiglycol, as the sole source of carbon and energy. The bacteria were capable of metabolizing MGHPs at a low temperature. The metabolic pathway for thiodiglycol degradation was proposed. The results suggest the potential for MGHPs biodegradation by naturally occurring populations of near-bottom-water and sediment microorganisms.

Human health risk screening due to consumption of fish contaminated with chemical warfare agents in the Baltic Sea

Chemical warfare agents (CWAs) have been disposed of in various fashions over the past decades. Significant amounts of CWA, roughly 11,000ton, have been dumped in the Baltic Sea east of the island Bornholm following the disarmament of Germany after World War II. This has caused concerns over potential human and environmental health risks, and resulted in restrictions on fishing in the dumpsite area. The purpose of this paper is to assess the potential indirect human health risks due to consumption of CWA-contaminated fish from the dumpsite area east of Bornholm. Earlier studies suggest that the fish community may be at risk from CWA exposure in the Bornholm basin. Moreover, elevated frequencies of lesions on fish caught in a CWA dumpsite in the Mediterranean Sea have been observed. The fish at the Mediterranean dumpsite had elevated total arsenic (As) concentrations in their tissue, and elevated total As levels were also observed in the sediment. Elevated total sediment As concentrations have also been recorded in CWA dumpsites in the Skagerrak and the Baltic Sea. Triphenylarsine and sulfur mustard gas (Yperite) are the CWAs with the greatest indirect human health risk potential. There are recognized uncertainties concerning Yperite's and CWA-derived arsenical's fate and speciation in the environment, as well as their inherent toxicity, warranting caution and further site-specific environmental and human health risk assessments of CWAs dumped in the Bornholm basin.

Multianalyte quantification of five sesqui- and ethyl ether oxy-mustard metabolites in human urine by liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry

Sesqui- and oxy-mustards pose a significant threat to military forces and civilians because they are potent vesicants. We have developed an isotope-dilution high-performance liquid chromatography-atmospheric pressure chemical ionization-tandem mass spectrometry method utilizing negative ion multiple reaction monitoring for the analysis of sesqui-mustard metabolites bis(2-hydroxyethylthio)alkanes (n = 1-5) and oxy-mustard metabolite bis(2-hydroxyethylthioethyl)ether in human urine. Relative standard deviations were < 10% and the reportable limits of detection were 1 ng/mL in 0.5 mL of urine. We applied this method to 100 samples collected from individuals with no known exposure to sesqui- or oxy-mustards, and no urines showed detectable levels of any of the analytes, suggesting that these metabolites may be used for monitoring exposure to sesqui- and oxy-mustards.

Analysis of urinary metabolites of sulfur mustard in two individuals after accidental exposure

In July 2004, two individuals developed blisters after the destruction of a WWI-era munition. To determine the causative agent, urine samples were collected from both the highly blistered patient (patient 1; 6.5% of total body surface area) and patient 2, who had only one small blister. Their urine was analyzed for metabolites of known vesicants including sulfur mustard (HD), Lewisite (L1), and nitrogen mustards. The urine samples only tested positive for metabolites of HD. Additional metabolites were measured to confirm the exposure of sulfur mustard agent HD, including thiodiglycol (TDG), TDG-sulfoxide, and the bis-mercapturate of mustard sulfone. On day 2 after the exposure, patient 1 had a beta-lyase metabolite level of 41 ng/mL, and patient 2 had a level of 2.6 ng/mL. Detectable levels of the beta-lyase metabolite were observed in patient 1 for 11 days and in patient 2 for 7 days. Levels of TDG and both TDG and its sulfoxide measured together in the urine of patient 1 were found to be 24 ng/mL and 50 ng/mL, respectively, on day 2. The bis-mercapturate of mustard sulfone was detected in patient 1 (3.1 ng/mL) on day 2 but was not detected in samples taken on subsequent days.

Detection of Chemical Weapon Agents and Simulants Using Chemical Ionization Reaction Time-of-Flight Mass Spectrometry

Chemical ionization reaction time-of-flight mass spectrometry (CIR-TOF-MS) has been used for the analysis of prepared mixtures of chemical weapon agents (CWAs) sarin and sulfur mustard. Detection of the CWA simulants 2-chloroethyl ethyl sulfide, triethyl phosphate, and dimethyl methyl phosphonate has also been investigated. Chemical ionization of all the agents and simulants was shown to be possible using the CIR-TOF-MS technique with a variety of reagent ions, and the sensitivity was optimized by variation of instrument parameters. The ionization process was found to be largely unaffected by sample humidity levels, demonstrating the potential suitability of the method to a range of environmental conditions, including the analysis of CWAs in air and in the breath of exposed individuals.

Selective and sensitive trace analysis of sulfur mustard with thermal desorption and two-dimensional gas chromatography–mass spectrometry

An improved method is presented for the trace analysis of sulfur mustard (HD) in biological samples, such as blood and tissue from laboratory animals. Using the internal standard method and liquid-liquid extraction with ethyl acetate, up to 400 microL of the extract was injected by thermal desorption from Tenax and analyzed by two-dimensional GC-MS/EI in SIM mode. The analysis was compared with a direct GC injection. Reversed thermal desorption was used as a tool for handling heavily contaminated (fat) samples, thus preventing contamination of the injection system and pre-column. A successful analytical configuration has been set up for the bioanalysis of HD at the low, toxicologically relevant pM level. A detection limit of 10 pg mL(-1) blood or pg g(-1) tissue of sulfur mustard (S/N=3) was established by using this configuration.

Plastic antibody for the recognition of chemical warfare agent sulphur mustard

Molecularly imprinted polymers (MIPs) known as plastic antibodies (PAs) represent a new class of materials possessing high selectivity and affinity for the target molecule. Since their discovery, PAs have attracted considerable interest from bio- and chemical laboratories to pharmaceutical institutes. PAs are becoming an important class of synthetic materials mimicking molecular recognition by natural receptors. In addition, they have been utilized as catalysts, sorbents for solid-phase extraction, stationary phase for liquid chromatography and mimics of enzymes. In this paper, first time we report the preparation and characterization of a PA for the recognition of blistering chemical warfare agent sulphur mustard (SM). The SM imprinted PA exhibited more surface area when compared to the control non-imprinted polymer (NIP). In addition, SEM image showed an ordered nano-pattern for the PA of SM that is entirely different from the image of NIP. The imprinting also enhanced SM rebinding ability to the PA when compared to the NIP with an imprinting efficiency (alpha) of 1.3.

Closed Cup Vapor Systems in Percutaneous Exposure Studies: What is the Dose?

Percutaneous vapor dosing studies have generally used saturated vapor concentration (SVC) measurements to estimate the exposure dose (Ct) of vapor produced from a volatile liquid within a closed system. The purpose of this study was to clarify whether the assumption was valid when translated to a biological system (pig skin) using sulfur mustard (SM) as a model skin penetrant. Three systems were evaluated, two containing skin and a control system (without skin). At set time points, samples from the headspace of each dosing system were extracted using a gas-tight syringe and analyzed by gas chromatography in conjunction with a flame-ionization detector. This demonstrated the rapid achievement of a constant vapor concentration within the biological and control systems and enabled a comparison with previously determined SVCs attained under ideal conditions. All three systems attained a constant vapor concentration within 2 min of exposure to SM. The control system reached an equilibrium vapor concentration of 1179 +/- 164 mg/m3, a value not significantly different from that derived from the SVC (1363 mg/m3). Because of absorption in the skin systems, SM vapor concentrations were significantly lower than that derived from the SVC and were dependent on the skin surface area within the dosing chamber (592 +/- 246 mg/m3 for a surface area of 10.15 cm2 and 740 +/- 224 mg/m3 for a surface area of 2.54 cm2). The assumption that SVC gives an acceptable measure of the Ct was shown to be valid by comparison with sulfur mustard recovered from the skin.

Surface-enhanced Raman spectroscopy of half-mustard agent

The detection and identification of chemical warfare agents is an important analytical goal. Herein, it is demonstrated that 2-chloroethyl ethyl sulfide (half-mustard, CEES) can be successfully analysed using surface-enhanced Raman spectroscopy (SERS). A critical component in this detection system is the fabrication of a robust, yet highly enhancing, sensor surface. Recent advances in substrate fabrication and in the fundamental understanding of the SERS phenomenon enable the development of improved substrates for practical SERS applications.

Determination of mustard and lewisite related compounds in abandoned chemical weapons (Yellow shells) from sources in China and Japan

Knowledge of the states of the contents in chemical munitions that Japanese Imperial Forces abandoned at the end of World War II in Japan and China is gravely lacking. To unearth and recover these chemical weapons and detoxify the contents safely, it is essential to establish analytical procedures to definitely determine the CWA contents. We established such a procedure and applied it to the analysis of chemicals in the abandoned shells. Yellow shells are known to contain sulfur mustard, lewisite, or a mixture of both. Lewisite was analyzed without thiol derivatization, because it and its decomposition products yield the same substances in the derivatization. Analysis using our new procedure showed that both mustard and lewisite remained as the major components after the long abandonment of nearly 60 years. The content of mustard was 43% and that of lewisite 55%. The viscous material found was suggested to be mostly oligomers of mustard. Comparison of the components in the Yellow agents with mustard recovered in both Japan and China showed a difference in the impurities between the CWAs produced by the former Imperial navy and those by the former Imperial army.

Preparation and application of the sol–gel-derived acrylate/silicone co-polymer coatings for headspace solid-phase microextraction of 2-chloroethyl ethyl sulfide in soil

Three types of novel acrylate/silicone co-polymer coatings, including co-poly(methyl acrylate/hydroxy-terminated silicone oil) (MA/OH-TSO), co-poly(methyl methacrylate/OH-TSO) (MMA/OH-TSO) and co-poly(butyl methacrylate/OH-TSO) (BMA/OH-TSO), were prepared for the first time by sol-gel method and cross-linking technology and subsequently applied to headspace solid-phase microextraction (HS-SPME) of 2-chloroethyl ethyl sulfide (CEES), a surrogate of mustard, in soil. The underlying mechanisms of the coating process were discussed and confirmed by IR spectra. The selectivity of the three types of sol-gel-derived acrylate/silicone coated fibers was studied, and the BMA/OH-TSO coated fibers exhibited the highest extraction ability to CEES. The concentration of BMA and OH-TSO in sol solution was optimized, and the BMA/OH-TSO (3:1)-coated fibers possessed the highest extraction efficiency. Compared with commercially available polyacrylate (PA) fiber, the sol-gel-derived BMA/OH-TSO (3:1) fibers showed much higher extraction efficiency to CEES. Therefore, the BMA/OH-TSO (3:1)-coated fibers were chosen for the analysis of CEES in soil matrix. The reproducibility of coating preparation was satisfactory, with the RSD 2.39% within batch and 3.52% between batches, respectively. The coatings proved to be quite stable at high temperature (to 350 degrees C) and in different solvents (organic or inorganic), thus their lifetimes (to 150 times) are longer than conventional fibers. Extraction parameters, such as the volume of water added to the soil, extraction temperature and time, and the ionic strength were optimized. The linearity was from 0.1 to 10 microg/g, the limit of detection (LOD) was 2.7 ng/g, and the RSD was 2.19%. The recovery of CEES was 88.06% in agriculture soil, 92.61% in red clay, and 101.95% in sandy soil, respectively.

On-matrix derivatisation–extraction of precursors of nitrogen- and sulfur-mustards for verification of chemical weapons convention

Development and refinement of sample preparation protocols for retrospective detection and identification of chemical warfare agents (CWAs) and their markers is of paramount importance from verification point of view of chemical weapons convention (CWC). Precursors of nitrogen- and sulfur-mustards (NMPs and SMPs) are polar adsorptive markers of vesicant class of CWAs. Their detection in a given environmental sample may imply past contamination with mustards. For the efficient extraction of NMPs and SMPs from soil, on-matrix derivatisation-extraction (OMDEX) method was developed and optimized. The method involved trifluoroacetylation of analytes on soil itself, followed by extraction with suitable solvent. The extracted samples were analyzed by gas chromatography-mass spectrometry (GC-MS). This virtually single-step sample preparation offered better recoveries of NMPs and SMPs in comparison to conventionally used extraction, evaporation and derivatisation. The best recoveries of analytes were obtained with acetonitrile by OMDEX method. Dynamic linearity range of trifluoroacetylated (TFA) derivatives of NMPs and SMPs was 1-12 microg/L in GC-MS analysis in SIM mode. Repeatability and reproducibility of this technique containing 5 and 10 microg analytes/gm soil was <3.3% and <4.6%, respectively. OMDEX technique was finally applied for the detection of TFA derivatives of NMPs in the soil sample supplied in 16th official proficiency test conducted by OPCW in October 2004.

Analysis of chemical warfare agents

Thermal desorption with gas chromatography-mass spectrometry (TD-GC-MS) remains the technique of choice for analysis of trace concentrations of analytes in air samples. This paper describes the development and application of a method for analysing the vesicant compounds sulfur mustard and Lewisites I-III. 3,4-Dimercaptotoluene and butanethiol were used to spike sorbent tubes and vesicant vapours sampled; Lewisite I and II reacted with the thiols while sulfur mustard and Lewisite III did not. Statistical experimental design was used to optimise thermal desorption parameters and the optimum method used to determine vesicant compounds in headspace samples taken from a decontamination trial. 3,4-Dimercaptotoluene reacted with Lewisites I and II to give a common derivative with a limit of detection (LOD) of 260 microg m(-3), while the butanethiol gave distinct derivatives with limits of detection around 30 microg m(-3).

Packed capillary liquid chromatography-electrospray ionization (tandem) mass spectrometry of mustard hydrolysis products in soil

A packed capillary liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method was developed and applied to the identification of mustard hydrolysis products in aqueous extracts of soil. In the first application the LC-ESI-MS/MS method was used to identify thiodiglycol and nine longer chain diols in soil samples taken at different locations and depths from a former mustard storage site as part of an ongoing environmental assessment. Aqueous extracts of the soil samples were analysed by LC-ESI-MS/MS using a quadrupole/time-of-flight tandem mass spectrometer operating with a resolution of 9000. High resolution product mass spectra were acquired for thiodiglycol, the hydrolysis product of mustard and nine other sulfur containing diols, including five longer chain diols that could not be identified during prior LC-ESI-MS analyses. The high resolution LC-ESI-MS/MS method was also incorporated into an analytical approach designed to provide rapid chemical warfare agent identification in cases where the chemical and/or biological warfare agent content of a sample is unknown. A sample handling method involving aqueous extraction of the soil sample in biocontainment level 3 (BL-3), followed by autoclave sterilization of the aqueous extract was developed. Once sterilized, the container and aqueous extract can then be safely manipulated outside of BL-3 in the analytical laboratories and may be analysed for the presence or absence of chemical warfare agents, their hydrolysis products or related compounds by LC-ESI-MS/MS.

Procedure for Monitoring Exposure to Sulfur Mustard Based on Modified Edman Degradation of Globin

A procedure for the modified Edman degradation of globin for determination of sulfur mustard adducts to the N-terminal valine residue in human hemoglobin has been developed for use under field laboratory conditions. The minimum detectable exposure level of human blood (in vitro) to sulfur mustard using this procedure is 100 nM. The interindividual and intraindividual variabilities of the procedure were acceptable (standard deviation < 10% and < 20%, respectively). The procedure could be properly set up and carried out in another laboratory within one working day, demonstrating its robustness.

A Rapid, Sensitive Method for the Quantitation of Specific Metabolites of Sulfur Mustard in Human Urine Using Isotope-Dilution Gas Chromatography-Tandem Mass Spectrometry

Sulfur mustard agent (HD) (2,2'-dichloroethyl sulfide), a Schedule I compound on the Chemical Weapons Convention Schedule of Chemicals, remains a public health concern because it is simple to synthesize and it is in the chemical weapon stockpiles of several countries. A sensitive, rapid, accurate, and precise method was developed to quantitate trace levels of 1,1'-sulfonylbis [2-(methylthio) ethane] (SBMTE) in human urine as a means of assessing exposure to HD. The method used immobilized liquid-liquid extraction with diatomaceous earth, followed by the analysis of the urine extract using isotope-dilution gas chromatography-tandem mass spectrometry. Relative standard deviations were less than 8.6% at 1 ng/mL and 3.6% at 20 ng/mL. The limit of detection for SBMTE was 0.038 ng/mL in 0.5 mL of urine.

Express analysis of explosives, chemical warfare agents and drugs with multicapillary column gas chromatography and ion mobility increment spectrometry

Description of a gas chromatograph designed for express analysis of explosives (2,4-dinitrotoluene, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate), chemical warfare agents (mustard gas, lewisite, sarin) and drugs (heroin, cocaine hydrochloride, crack) is given. The devices comprises a multicapillary chromatographic column and an ion mobility increment spectrometer (MCC-IMIS). The main analytical characteristics of an IMIS (estimated detection limit (DL), linear dynamic range (LDR), speed of response) and a chromatographic column (separation power, degree of separation, a number of possible peaks at a chromatogram section, divided by analysis time) are determined. The maximum value of DL equal to 5 pg/ml was registered for cis-alpha-LW, and the lowest one of 0.001 pg/ml was for cocaine. The maximum value of LDR equal to 1000 was registered for sarin and the lowest one of 150 was for the ions of lewisite. Speed of response of one compound detection with the IMIS was 0.7 s.

Degradation of VX and sulfur mustard by enzymatic haloperoxidation

Chloroperoxidase (CPO) isolated from Caldariomyces fumago (20 U ml(-1)) together with urea hydrogenperoxide (UPER, 0.5 mM) and sodium chloride as co-substrate (NaCl, 0.5 M) caused rapid breakdown of VX (10 microM) (t((1/2)) = 8 s, 25 C, 50 mM tartarate, pH 2.75). Glucose oxidase (GOX, Aspergillus niger) and glucose were used as an alternative source for H(2)O(2). A mixture of GOX (20 U ml(-1)), glucose (GLU 0.45 M), CPO (20 U ml(-1)) and NaCl (0.5 M) caused a 3.8-fold slower degradation of VX (10 microM) (t((1/2)) = 30 s, 25 C, 50 mM tartarate, pH 2.75). The concentrations of H(2)O(2) and chlorine produced by this enzyme/substrate mixture depended mainly on the GLU concentration. Horseradish peroxidase (HRP) together with UPER (1 mM) and sodium iodide (NaI, 0.05 M) caused progressive degradation of VX that was more than 400-fold slower than with CPO (20 U ml(-1)), UPER (0.5 mM) and NaCl (0.5 M) (t((1/2)) = 55 min, 25 C, pH 8). Skin decontamination of VX by CPO was tested in pig-ear skin in vitro. The chemical agent VX (0.01 M, 100 microl) was degraded by 98% within 3 h of skin diffusion when a mixture of UPER/NaCl/CPO was applied 60 min prior to VX application. A mixture of UPER/NaCl without CPO also caused significant VX degradation (94%) during skin diffusion whereas it did not cause any VX degradation in solution. Degradation of VX in skin, obtained without exogenous CPO, may indicate involvement of endogenous intradermal haloperoxidase-like enzyme. Reagent UPER (1 mM) did not cause any degradation of VX in solution or during its skin diffusion. Furthermore, a mixture of CPO, UPER and NaCl caused rapid degradation of sulfur mustard (HD). Sulfur mustard (50 microM) incubated in the presence of CPO (4 U ml(-1)), UPER (0.05 M) and NaCl (0.5 M) at pH 2.75 and 30 C was oxidized by 97% and 99% within 5 and 10 min, respectively. The oxidation products HD sulfoxide, HD sulfone and HD sulfoxidevinyl were identified by GC/MS in the enzymatic chloroperoxidation mixture.

Mass spectrometric analysis of chemical warfare agents and their degradation products in soil and synthetic samples

A packed capillary liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method was developed for the identification of chemical warfare agents, their degradation products and related compounds in synthetic tabun samples and in soil samples collected from a former mustard storage site. A number of organophosphorus and organosulfur compounds that had not been previously characterized were identified, based on acquired high-resolution ESI-MS data. At lower sampling cone voltages, the ESI mass spectra were dominated by protonated, sodiated and protonated acetonitrile adducts and/or their dimers that could be used to confirm the molecular mass of each compound. Structural information was obtained by inducing product ion formation in the ESI interface at higher sampling cone voltages. Representative ESI-MS mass spectra for previously uncharacterized compounds were incorporated into a database as part of an on-going effort in chemical warfare agent detection and identification. The same samples were also analyzed by capillary column gas chromatography (GC)-MS in order to compare an established method with LC-ESI-MS for chemical warfare agent identification. Analysis times and full-scanning sensitivities were similar for both methods, with differences being associated with sample matrix, ease of ionization and compound volatility. GC-MS would be preferred for organic extracts and must be used for the determination of mustard and relatively non-polar organosulfur degradation products, including 1,4- thioxane and 1,4-dithiane, as these compounds do not ionize during ESI-MS. Diols, formed following hydrolysis of mustard and longer-chain sulfur vesicants, may be analyzed using both methods with LC-ESI-MS providing improved chromatographic peak shape. Aqueous samples and extracts would, typically, be analyzed by LC-ESI-MS, since these analyses may be conducted directly without the need for additional sample handling and/or derivatization associated with GC-MS determinations. Organophosphorus compounds, including chemical warfare agents, related compounds and lower volatility hydrolysis products may all be determined during a single LC-ESI- MS analysis. Derivatization of chemical warfare agent hydrolysis products and other compounds with hydroxyl substitution would be required prior to GC-MS analysis, giving LC-ESI-MS a definite advantage over GC-MS for the analysis of samples containing chemical warfare agents and/or their hydrolysis products.

Application of headspace solid-phase microextraction and gas chromatography-mass spectrometry for detection of the chemical warfare agent bis(2-chloroethyl) sulfide in soil

A field expedient analytical method for detecting the chemical warfare agent (CWA) sulfur mustard as a soil contaminant was developed using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Five commercially available SPME fibers were investigated to determine the optimal fiber, and extraction conditions. Polyacrylate and carbowax-divinylbenzene fiber coatings gave a statistically indistinguishable and best response compared to the other three types examined in a simple system studied without soil. The polyacrylate fiber coating was selected for study of a system in which sulfur mustard was spiked to an agricultural soil (Standard Reference Material 2709, San Joaquin type). With soil samples, the greatest sensitivity occurred by the addition of deionized water to spiked soil and extraction at ambient temperature for 20 min or longer. SPME sampling with GC-MS analyses afforded good reproducibility (relative standard deviation between 2 and 10%), and analyte concentrations as low as 237 ng/g were detected in soil (total ion chromatograms). As completed here, total time for sampling and analysis was just under 1 h, and use of organic solvents or special sample introduction equipment was avoided.