Detection Of Chemical Warfare Agents Research Articles

Reliable Detection of Chemical Warfare Agents Using High Kinetic Energy Ion Mobility Spectrometry.

High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) ionize and separate ions at reduced pressures of 10-40 mbar and over a wide range of reduced electric field strengths E/N of up to 120 Td. Their reduced operating pressure is distinct from that of conventional drift tube ion mobility spectrometers that operate at ambient pressure for trace compound detection. High E/N can lead to a field-induced fragmentation pattern that provides more specific structural information about the analytes. In addition, operation at high E/N values adds the field dependence of ion mobility as an additional separation dimension to low-field ion mobility, making interfering compounds less likely to cause a false positive alarm. In this work, we study the chemical warfare agents tabun (GA), sarin (GB), soman (GD), cyclosarin (GF) and sulfur mustard (HD) in a HiKE-IMS at variable E/N in both the reaction and the drift region. The results show that varying E/N can lead to specific fragmentation patterns at high E/N values combined with molecular signals at low E/N. Compared to the operation at a single E/N value in the drift region, the variation of E/N in the drift region also provides the analyte-specific field dependence of ion mobility as additional information. The accumulated data establish a unique fingerprint for each analyte that allows for reliable detection of chemical warfare agents even in the presence of interfering compounds with similar low-field ion mobilities, thus reducing false positives.

Hydrogen-Bond Acidic Materials in Acoustic Wave Sensors for Nerve Chemical Warfare Agents' Detection.

The latest trends in the field of the on-site detection of chemical warfare agents (CWAs) involve increasing the availability of point detectors to enhance the operational awareness of commanders and soldiers. Among the intensively developed concepts aimed at meeting these requirements, wearable detectors, gas analyzers as equipment for micro- and mini-class unmanned aerial vehicles (UAVs), and distributed sensor networks can be mentioned. One of the analytical techniques well suited for use in this field is surface acoustic wave sensors, which can be utilized to construct lightweight, inexpensive, and undemanding gas analyzers for detecting CWAs. This review focuses on the intensively researched and developed variant of this technique, utilizing absorptive sensor layers dedicated for nerve CWAs' detection. The paper describes the mechanism of the specific interaction occurring between the target analyte and the sensing layer, which serves as the foundation for their selective detection. The main section of this paper includes a chronological review of individual achievements in the field, largely based on the peer-reviewed scientific literature dating back to the mid-1980s to the present day. The final section presents conclusions regarding the prospects for the development of this analytical technique in the targeted application.

Accurate Detection of G-Series Agent Simulants by Pseudo-Multiple Reaction Monitoring on Miniature LIT-MS.

Rapid and accurate on-site detection of chemical warfare agents (CWAs) could defend military and civilian populations against current and emerging chemical weapons. With the development of ambient ionization and linear ion trap technology, the rapid and accurate quantitative determination method of CWAs based on direct ionization and multistage mass spectrometry has attracted widespread attention. In this study, a microliter electrospray ionization-miniature linear ion trap mass spectrometry (LIT-MS) instrument was designed and constructed, and the effects of quadrupole enhanced dipole resonance excitation on the resolution and sensitivity were investigated; consequently, the parameters of CWAs detection were optimized. Based on the broad time-frequency ion excitation technology, accurate multiple reaction monitoring (MRM) quantitative analysis of DMMP (G-series agent simulants, m/z 125 → m/z 93) was obtained. The linear correlation coefficient in the concentration range of 1 to 20 μg/mL could reach 99.02%, and the relative standard deviations (RSD) of continuous repeatability, interday repeatability, and intraday repeatability were all less than 10%. The results showed that the accurate pseudo-MRM detection method based on miniature linear ion trap mass spectrometry for CWAs detection was feasible.

Electrochemical sensing and detection of phosgene and thiophosgene chemical warfare agents (CWAs) by all-boron B38 fullerene analogue: a DFT insight

Abstract Chemical warfare agents (CWAs) are very toxic and dangerous to all forms of life. With the purpose of protecting environment and human health, it is essential to identify and eliminate these threats quickly and effectively. B38 nanocage as a sensor is rarely discussed therefore the detection of harmful CWAs (phosgene and thiophosgene) by using the B38 nanocage has been examined using density functional theory (DFT) parameters. Optimized geometries, adsorption energies, NCI, NBO, FMO and QTAIM studies have been used to analyze the interactions between CWAs and the B38 nanocage. The adsorption energy values indicate that CWAs are adsorbed on the B38 nanocage in a stable manner and the reaction is exothermic. The complex T-S@B38-B have the greatest conductivity, lowest stability and maximum sensitivity due to its narrow energy gap of 1.9648 eV while complex T-S@B38-6r, with the highest energy gap of 1.9988 eV is the most stable. The global reactivity parameters indicate that the complex T-S@B38-B has the highest electrophilicity index, the lowest chemical hardness and the highest chemical softness and resultantly leads to highest sensitivity. Van der Waals forces are present between the B38 nanocage and CWAs as shown by NCI and QTAIM studies. The formation of new energy level in PDOS of B38 results into the interaction of CWAs with the surface of B38. Nanocage sensing capacity is evaluated by measuring E g value, sensitivity and recovery time of the complex. B38 has the highest sensitivity and shortest recovery time for T-S@B38-B and P-Cl@B38-B complex with 5.90 × 10−3 and 2.78259 × 10−12 s values which results the B38 nanocage is more effective sensor for detecting CWAs. Consequently, B38 nanocage is recommended as fine future sensor for the sensing of phosgene and thiophosgene.

Toward Remote Detection of Chemical Warfare Simulants Using a Miniature Potentiostat

A miniaturized electrochemical sensor was developed for the remote detection of chemical warfare agent (CWA) simulants. To facilitate drone-based remote sensing, this present study focuses on advancing the miniaturized and compact electrochemical sensor for monitoring two CWA simulants, diisopropyl fluorophosphate (DFP) and O,S-diethylmethylphosphonothioate (O,S-DEMPT). The differential pulse voltammetry (DPV) signal was processed, and the DPV signature features were extracted on the basis of the redox properties associated with the absence and the presence of DFP and O,S-DEMPT. Upon the addition of 0.10 equivalence of DFP or O,S-DEMPT, a shift in potential (E) of ~0.13 V was recorded. The limit of detection (LOD) was calculated to be 0.25 µM (0.046 ppm) and 0.10 µM (0.017 ppm) for DFP and O,S-DEMPT, respectively. These results were validated using a portable Palmsens Emstat HR potentiostat, which corroborated the results obtained using a lab benchtop potentiostat. Additionally, Boolean logic (“AND” operation) was implemented for future drone technology deployment. This advancement enables the fabrication of a networked device capable of autonomously executing tasks without constant oversight.

Designing one-dimensional covalent organic frameworks: novel post-synthetic modification on hydroxyl groups and ratiometric detection of chemical warfare agent mimics

A post-synthetic modification based on substitution reaction of the hydroxyl group in COFs is utilized to construct a dual-emission hybrid material for real-time detection of 2-chloroethyl ethyl sulfide (2-CEES) and diethyl cyanophosphonate (DCNP), mimics of chemical warfare agents.

Detection of sulfur mustard simulant by trisaryl phosphoric triamide-based resin using a quartz crystal microbalance sensor.

Chemical warfare agents (CWAs) pose a persistent threat to human safety, and bis(2-chloroethyl) sulfide, or sulfur mustard (SM) is one of the most dangerous substances and is able to cause serious harm. Detecting SM gas is vital, but current methods have high-temperature requirements and limited selectivity, mainly because of the lack of CWA receptor development, and this makes them challenging to use. To address this issue, we present a trisaryl phosphoric triamide-based resin receptor that preferentially interacts with a SM simulant 2-chloroethyl ethyl sulfide (2-CEES) through dipole interactions. The receptor was synthesized through a facile process using an amine and a triethyl phosphate and the properties of its coating were enhanced using epoxy chemistry. The receptor's superior triamide structure was evaluated using a quartz crystal microbalance and reactivity was confirmed by observing the variations in reactivity according to the number of phosphoramides. The receptor showed better reactivity to 2-CEES vapor than to the known poly(epichlorohydrin) and showed selectivity to other volatile organic compounds. Moreover, its durability was evident even 30 days post-coating. The applicability of this receptor extends to array sensors, sound acoustic wave sensors, and chemo-resistive and chemo-capacitive sensors, and it promises advances in chemical warfare agent detection.

Highly sensitive chemiluminescence sensors for the detection and differentiation of chemical warfare agents.

Highly sensitive chemiluminescence-based probes that effectively detect and differentiate between the extremely toxic real G- and V-type organophosphorus chemical warfare agents (OPCWAs) are presented. This straightforward approach does not require any instrumentation or light source; hence, it appears ideal for the future development of field colorimetric detectors.

Rapid Non-Contact Detection of Chemical Warfare Agents by Laser Photoacoustic Spectroscopy.

Nerve agents have recently been used in battlefield operations, espionage wars, and terrorist attacks. These compounds, like some pesticides, cause organophosphate poisoning. The rapid, noncontact detection of a sarin simulant in the liquid phase has been demonstrated at the Diagnostics and Metrology Laboratory of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development using laser photoacoustic spectroscopy, an infrared absorption technology. The first measurements, carried out with an experimental system based on a quantum cascade laser and developed for the assessment of food authenticity in the "fingerprint region", show that a detection limit of one nanolitre is within the reach of the instrument when chemometric analysis is applied.

Highly Selective Detection of Large-Sized Chemical Warfare Agents via Interface-Controlled Diffusion Channels of Graphene Oxide Frameworks

Highly Selective Detection of Large-Sized Chemical Warfare Agents via Interface-Controlled Diffusion Channels of Graphene Oxide Frameworks

A high-performance standalone planar FAIMS system for effective detection of chemical warfare agents via TSPSO algorithm

A high-performance standalone planar field asymmetric waveform ion mobility spectrometry (p-FAIMS) system with a deconvolution algorithm (two-step particle swarm optimization algorithm, TSPSO) for overlapping peaks was developed to effectively detect chemical warfare agents (CWAs). Four CWA simulants were applied in this study to systemically evaluate the performance of the standalone p-FAIMS system. The experimental results showed that each CWA simulant in the mixture can be positively identified by carefully comparing the compensation voltage (CV) value of each peak in the FAIMS spectra for the mixture to the ones in the spectra acquired by using the same FAIMS system for the pure CWA simulant standards. The FAIMS spectrum of the CWA simulant mixture might consist of multiple overlapping peaks, which would be difficult to accurately determine the CV value for each CWA simulant peak. This problem has been effectively resolved in this study by deconvoluting the overlapping peaks via the TSPSO algorithm. As the effective peak deconvolution via TSPSO requires the degree of overlap between each FAIMS peak to be lower than a specific value, the flow rate of FAIMS carrier gas was decreased to further improve the resolution of the p-FAIMS system. After the accurate deconvolution, the resolution of original FAIMS spectrum can also be enhanced to achieve baseline separation by using TSPSO algorithm to narrow the peak width of each peak. The experimental results in this study demonstrated the possibility of using TSPSO algorithm to achieve high-resolution on a typically low-resolution standalone FAIMS. The concept in this study can potentially be applied to any low-resolution instruments to achieve high-resolution results.

Design Analysis of Mid IR DIAL System for Detection of Hazardous Chemical Species

Nowadays, both military and public agencies are concerned with the remote detection of toxic gases and chemical warfare agents in the atmosphere. A promising method for the remote detection of such harmful chemicals in the atmosphere is Differential Absorption Lidar (DIAL). In the current paper, system design analysis has been carried out to build a DIAL system for the detection of toxic chemical warfare agents, chemical warfare simulants, explosive precursors, and pollutants. The proposed DIAL system comprises an Optical Parametric Oscillator (OPO) based tuneable laser, a 203 mm diameter Cassegrain telescope, a TE-cooled MCT detector, suitable data acquisition hardware, etc. The DIAL output parameters like return signals, SNR, and minimum measurable concentrations have been simulated under different weather conditions such as clear sky, moderately hazy sky, and hazy atmospheric conditions for given system input parameters (pulse energy, detectivity, bandwidth, DAQ resolution, etc.). We have considered chemicals such as Sarin, Thiodiglycol (TDG), acetone, and methane to be detected using the system. Analysis has been carried out for these chemicals present at different locations with varying concentrations. Our analysis reveals that the DIAL system with a laser transmitter of 5 mJ energy and 203 mm receiver telescope is capable of detecting a few ppm concentrations of toxic chemicals present anywhere between the ranges from a few tens of meters to 2 km with topographic target present. The sensitivity of the system in terms of minimum detectable concentrations for the considered chemicals is also estimated for different atmospheric conditions. It is seen that the minimum detectable concentration of TDG is 3.2 ppm in clear weather conditions which increases to 9.2 ppm under a hazy atmosphere. A similar analysis has been carried out for other toxic chemicals and has been discussed in the paper.

Ni-rGO Sensor Combined with Human Olfactory Receptor-Embedded Nanodiscs for Detecting Gas-Phase DMMP as a Simulant of Nerve Agents.

Nerve agents are organophosphorus toxic chemicals that can inhibit acetylcholinesterase, leading to paralysis of the nervous system and death. Early detection of nerve agents is important for safety issues. Dimethyl methylphosphonate (DMMP) is widely used as a simulant of nerve agents, and many studies have been conducted using DMMP as a substitute for detecting nerve agents. Despite many studies on sensors for detecting DMMP, they have limitations in sensitivity and selectivity. To overcome these limitations, a nickel-decorated reduced graphene oxide (Ni-rGO) sensor with human olfactory receptor hOR2T7 nanodiscs was utilized to create a bioelectronic nose platform for DMMP gas detection. hOR2T7 was produced and reconstituted into nanodiscs for enhancing the sensor's stability, especially for detection in a gas phase. It could detect DMMP gas selectively and repeatedly at a concentration of 1 ppb. This sensitive and selective bioelectronic nose can be applied as a practical tool for the detection of gaseous chemical warfare agents in military and safety fields.

Polypyrrole Nanoparticles Suspended on Graphene for the Detection of Simulant Chemical Warfare Agents

Polypyrrole Nanoparticles Suspended on Graphene for the Detection of Simulant Chemical Warfare Agents

Detection of sulfur mustard simulants using the microwave atmospheric pressure plasma optical emission spectroscopy method.

Sulfur mustard (SM) is one kind of highly toxic chemical warfare agent and easy to spread, while existing detection methods cannot fulfill the requirement of rapid response, good portability, and cost competitiveness at the same time. In this work, the microwave atmospheric pressure plasma optical emission spectroscopy (MW-APP-OES) method, taking the advantage of non-thermal equilibrium, high reactivity, and high purity of MW plasma, is developed to detect three kinds of SM simulants, i.e., 2-chloroethyl ethyl sulfide, dipropyl disulfide, and ethanethiol. Characteristic OES from both atom lines (C I and Cl I) and radical bands (CS, CH, and C2) is identified, confirming MW-APP-OES can preserve more information about target agents without full atomization. Gas flow rate and MW power are optimized to achieve the best analytical results. Good linearity is obtained from the calibration curve for the CS band (linear coefficients R 2 > 0.995) over a wide range of concentrations, and a limit of detection down to sub-ppm is achieved with response time on the order of second. With SM simulants as examples, the analytical results in this work indicate that MW-APP-OES is a promising method for real-time and in-site detection of chemical warfare agents.

Fast Response-Recovery and High Selectivity Chemicapacitive Detection of a Nerve Agent Simulant Vapor

Early detection of chemical warfare agents (CWAs) is critical in minimizing the exposure to chemical threats. This study presents a fast response-recovery chemicapacitive sensor (chemicapacitor) for a nerve agent simulant, dimethyl methylphosphonate (DMMP), with high selectivity and sensitivity. Chemicapacitors with interdigitated electrodes were fabricated on a SiO2/Si wafer by aligning single-walled carbon nanotubes (SW-CNTs) coated with polyhedral oligomeric silsesquioxane-supported 1,1,1,3,3,3-hexafluoro-2-propanol (POSS-HFIP) receptors. The stable, nano-sized three-dimensional structure with multiple terminal alcohol groups played a crucial role as a high-performance receptor via efficient hydrogen-bonding interaction with the CWA simulant. The response and recovery times of the fabricated chemicapacitors were estimated to be 13 and 88 s, respectively, outperforming chemiresistive sensors in terms of response-recovery dynamics. The capacitive responses were obtained at varying DMMP vapor concentrations, ranging from 25 to 150 ppm, and they exhibited superior sensitivity compared to receptor-free sensor devices. The concentration-dependent sensitivity was well-fitted with the Langmuir isotherm model, indicating that the sensing mechanism is based on the adsorption/desorption process. In addition, excellent selectivity was realized by introducing different toxic molecules (sulfur dioxide, ammonia, and ethylene oxide) and a blood agent (cyanogen chloride), where the fabricated POSS-HFIP/SW-CNTs chemicapacitor selectively responded to the DMMP vapor. The limit-of-detection was calculated to be 0.70 ppm. The proposed POSS-HFIP/SW-CNTs chemicapacitor demonstrated rapid response-recovery characteristics (with improved selectivity towards DMMP), suggesting its potential in reducing casualties or injuries by early identification of CWAs.

Molybdenum Carbide MXenes as Efficient Nanosensors toward Selected Chemical Warfare Agents

There has been budding demand for the fast, reliable, inexpensive, non-invasive, sensitive, and compact sensors with low power consumption in various fields, such as defense, chemical sensing, healthcare, and safe environmental monitoring units. Particularly, efficient detection of chemical warfare agents (CWAs) is of great importance for human safety and security. Inspired by this, we explored molybdenum carbide MXenes (Mo2CTx; Tx = O, F, and S) as efficient sensors toward selected CWAs, such as arsine (AsH3), mustard gas (C4H8Cl2S), cyanogen chloride (NCCl), and phosgene (COCl2) both in aqueous and non-aqueous media. Our calculations based on van der Waals-corrected density functional theory (DFT) revealed that the CWAs bind with Mo2CF2, and Mo2CS2 monolayers under strong chemisorption with binding energies in the range of −2.33 to −4.05 eV, whereas Mo2CO2 resulted in comparatively weak bindings of −0.29 to −0.58 eV. We further reported the variations in the electronic properties, electrostatic potentials, and work functions of Mo2CTx upon the adsorption of CWAs, which authenticated an efficient sensing mechanism toward CWA detection. Statistical thermodynamic analysis was applied to explore the sensing properties of Mo2CTx at various temperatures and pressures. These findings will pave the way to an innovative class of low-cost reusable sensors for the sensitive and selective detection of highly toxic CWAs in air as well as in aqueous media.

Risk assessment based on dose-responsive and time-responsive genes to build PLS-DA models for exogenously induced lung injury

Xenobiotics can easily harm human lungs owing to the openness of the respiratory system. Identifying pulmonary toxicity remains challenging owing to several reasons: 1) no biomarkers for pulmonary toxicity are available that might help to detect lung injury; 2) traditional animal experiments are time-consuming; 3) traditional detection methods solely focus on poisoning accidents; 4) analytical chemistry methods hardly achieve universal detection. An in vitro testing system able to identify the pulmonary toxicity of contaminants from food, the environment, and drugs is urgently needed. Compounds are virtually infinite, whereas toxicological mechanisms are countable. Therefore, universal methods to identify and predict the risks of contaminants can be designed based on these well-known toxicity mechanisms. In this study, we established a dataset based on transcriptome sequencing of A549 cells upon treatment with different compounds. The representativeness of our dataset was analyzed using bioinformatics methods. Artificial intelligence methods, namely partial least squares discriminant analysis (PLS-DA) models, were employed for toxicity prediction and toxicant identification. The developed model predicted the pulmonary toxicity of compounds with a 92 % accuracy. These models were submitted to an external validation using highly heterogeneous compounds, which supported the accuracy and robustness of our developed methodology. This assay exhibits universal potential applications for water quality monitoring, crop pollution detection, food and drug safety evaluation, as well as chemical warfare agent detection.

BIOSENSORS: TYPES, APPLICATIONS, AND FUTURE ADVANTAGES

With the developing technology and increasing population, nanotechnology has started to be used in all areas of life. The use of biosensors, which have an important place in the field of nanotechnology, is increasing day by day. Biosensors can be defined as biological devices that help us interpret the analyte concentration in a sample by converting it into measurable signals. Advantageously, it has both speed and high precision. There are many types of biosensors used in many fields. These; enzymatic, nucleic acid, electrochemical and optical biosensors. All of them can have different components and uses. Biosensors are used especially in early diagnosis of diseases, environment and agriculture, pharmaceutical industry, defense industry and food industry. For example, biosensors are used in the treatment of oncological diseases using electrochemical impedance spectroscopy, in the determination of pesticides, which is one of the environmental pollutants, in the potentiometric analysis of glutamate, in the detection of chemical warfare agents and toxic substances. In addition, it is expected that the usage areas of biosensors will become widespread in the future, and they will be used more widely in the early diagnosis of diseases. At this point, the use of biosensors has increased worldwide and has attracted the attention of scientists. In this study, classification of biosensors, application areas, characterization, studies on biosensors, technologies developed and applied for the future are mentioned.

Semiconductor Gas Sensors for Detecting Chemical Warfare Agents and Their Simulants

On-site detection of chemical warfare agents (CWAs) can be performed by various analytical techniques. Devices using well-established techniques such as ion mobility spectrometry, flame photometry, infrared and Raman spectroscopy or mass spectrometry (usually combined with gas chromatography) are quite complex and expensive to purchase and operate. For this reason, other solutions based on analytical techniques well suited to portable devices are still being sought. Analyzers based on simple semiconductor sensors may be a potential alternative to the currently used CWA field detectors. In sensors of this type, the conductivity of the semiconductor layer changes upon interaction with the analyte. Metal oxides (both in the form of polycrystalline powders and various nanostructures), organic semiconductors, carbon nanostructures, silicon and various composites that are a combination of these materials are used as a semiconductor material. The selectivity of a single oxide sensor can be adjusted to specific analytes within certain limits by using the appropriate semiconductor material and sensitizers. This review presents the current state of knowledge and achievements in the field of semiconductor sensors for CWA detection. The article describes the principles of operation of semiconductor sensors, discusses individual solutions used for CWA detection present in the scientific literature and makes a critical comparison of them. The prospects for the development and practical application of this analytical technique in CWA field analysis are also discussed.