Read by QxMD icon Read

VX gas

Avinoam Bar-Zion, Charles Tremblay-Darveau, Oren Solomon, Dan Adam, Yonina Eldar
Ultrasound super-localization microscopy techniques presented in the last few years enable non-invasive imaging of vascular structures at the capillary level by tracking the flow of ultrasound contrast agents (gas microbubbles). However, these techniques are currently limited by low temporal resolution and long acquisition times. Super-resolution optical fluctuation imaging (SOFI) is a fluorescence microscopy technique enabling sub-diffraction limit imaging with high temporal resolution by calculating high order statistics of the fluctuating optical signal...
August 15, 2016: IEEE Transactions on Medical Imaging
Carlos A Valdez, Roald N Leif, Armando Alcaraz
The effective methylation of phosphonic acids related to chemical warfare agents (CWAs) employing trimethyloxonium tetrafluoroborate (TMO·BF4) for their qualitative detection and identification by gas chromatography-mass spectrometry (GC-MS) is presented. The methylation occurs in rapid fashion (1 h) and can be conveniently carried out at ambient temperature, thus providing a safer alternative to the universally employed diazomethane-based methylation protocols. Optimization of the methylation parameters led us to conclude that methylene chloride was the ideal solvent to carry out the derivatization, and that even though methylated products can be observed surfacing after only 1 h, additional time was not found to be detrimental but beneficial to the process particularly when dealing with analytes at low concentrations (∼10 μg mL(-1))...
August 24, 2016: Analytica Chimica Acta
Varoon Singh, Ajay Kumar Purohit, Sridhar Chinthakindi, Raghavender D Goud, Vijay Tak, Deepak Pardasani, Anchal Roy Shrivastava, Devendra Kumar Dubey
A simple, sensitive and low temperature sample preparation method is developed for detection and identification of Chemical Warfare Agents (CWAs) and scheduled esters in organic liquid using magnetic dispersive solid phase extraction (MDSPE) followed by gas chromatography-mass spectrometry analysis. The method utilizes Iron oxide@Poly(methacrylic acid-co-ethylene glycol dimethacrylate) resin (Fe2O3@Poly(MAA-co-EGDMA)) as sorbent. Variants of these sorbents were prepared by precipitation polymerization of methacrylic acid-co-ethylene glycol dimethacrylate (MAA-co-EGDMA) onto Fe2O3 nanoparticles...
May 27, 2016: Journal of Chromatography. A
D L'Hermite, E Vors, T Vercouter, G Moutiers
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)...
May 2016: Environmental Science and Pollution Research International
Rafał Sokołowski, Tadeusz Płusa
Organophosphates are stable cholinesterases inhibitors (AChE). Inhibition of AChE activity leads to the accumulation of large amounts of acetylcholine and hyperactivity of the cholinergic system by stimulating acetylcholine receptors - muscarinic and nicotinic. This group included tabun, sarin, soman and VX gases. Exposure to gaseous form causes symptoms within a few seconds of exposure. This depends on the gas concentration in the atmosphere. The most sensitive organ is the eyes and the respiratory system...
September 2015: Polski Merkuriusz Lekarski: Organ Polskiego Towarzystwa Lekarskiego
Sam Gon Ryu, Hae Wan Lee
The nerve agent, O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) must be promptly eliminated following its release into the environment because it is extremely toxic, can cause death within a few minutes after exposure, acts through direct skin contact as well as inhalation, and persists in the environment for several weeks after release. A mixture of hydrogen peroxide vapor and ammonia gas was examined as a decontaminant for the removal of VX on solid surfaces at ambient temperature, and the reaction products were analyzed by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectrometry (NMR)...
2015: Journal of Environmental Science and Health. Part A, Toxic/hazardous Substances & Environmental Engineering
Mieko Kanamori-Kataoka, Yasuo Seto
To establish adequate on-site solvent trapping of volatile chemical warfare agents (CWAs) from air samples, we measured the breakthrough volumes of CWAs on three adsorbent resins by an elution technique using direct electron ionization mass spectrometry. The trapping characteristics of Tenax(®) TA were better than those of Tenax(®) GR and Carboxen(®) 1016. The latter two adsorbents showed non-reproducible breakthrough behavior and low VX recovery. The specific breakthrough values were more than 44 (sarin) L/g Tenax(®) TA resin at 20°C...
September 4, 2015: Journal of Chromatography. A
Takahiro Iwai, Ken Kakegawa, Mari Aida, Hisayuki Nagashima, Tomoki Nagoya, Mieko Kanamori-Kataoka, Hidekazu Miyahara, Yasuo Seto, Akitoshi Okino
A gas-cylinder-free plasma desorption/ionization system was developed to realize a mobile on-site analytical device for detection of chemical warfare agents (CWAs). In this system, the plasma source was directly connected to the inlet of a mass spectrometer. The plasma can be generated with ambient air, which is drawn into the discharge region by negative pressure in the mass spectrometer. High-power density pulsed plasma of 100 kW could be generated by using a microhollow cathode and a laboratory-built high-intensity pulsed power supply (pulse width: 10-20 μs; repetition frequency: 50 Hz)...
June 2, 2015: Analytical Chemistry
Takafumi Satoh, Shintaro Kishi, Hisayuki Nagashima, Masumi Tachikawa, Mieko Kanamori-Kataoka, Takao Nakagawa, Nobuyoshi Kitagawa, Kenichi Tokita, Soichiro Yamamoto, Yasuo Seto
The ion mobility behavior of nineteen chemical warfare agents (7 nerve gases, 5 blister agents, 2 lachrymators, 2 blood agents, 3 choking agents) and related compounds including simulants (8 agents) and organic solvents (39) was comparably investigated by the ion mobility spectrometry instrument utilizing weak electric field linear drift tube with corona discharge ionization, ammonia doping, purified inner air drift flow circulation operated at ambient temperature and pressure. Three alkyl methylphosphonofluoridates, tabun, and four organophosphorus simulants gave the intense characteristic positive monomer-derived ion peaks and small dimer-derived ion peaks, and the later ion peaks were increased with the vapor concentrations...
March 20, 2015: Analytica Chimica Acta
Tomoko Imasaka, Totaro Imasaka
Excitation energies, oscillator strengths, and vacuum-ultraviolet/deep-ultraviolet absorption spectra were calculated for nerve agents, such as sarin, soman, VX, tabun, mustard gas, and analogs. We used time-dependent density functional theory (TD-DFT) methods that included B3LYP combined with basis sets of cc-pVDZ and cc-pVTZ, and ωB97XD with cc-pVTZ. The vertical ionization energies were also calculated for these compounds, in order to collect additional information relative to the optimal pathways for multiphoton ionization in mass spectrometry...
2014: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Jia-Bi Ma, Zhen Yuan, Jing-Heng Meng, Qing-Yu Liu, Sheng-Gui He
The reactivity of metal oxide clusters toward hydrocarbon molecules can be changed, tuned, or controlled by doping. Cerium-doped vanadium cluster cations CeV2O7(+) are generated by laser ablation, mass-selected by a quadrupole mass filter, and then reacted with C2H4 in a linear ion trap reactor. The reaction is characterized by a reflectron time-of-flight mass spectrometer. Three types of reaction channels are observed: 1) single oxygen-atom transfer , 2) double oxygen-atom transfer , and 3) C=C bond cleavage...
December 15, 2014: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Matthew R Gravett, Farrha B Hopkins, Adam J Self, Andrew J Webb, Christopher M Timperley, Matthew J Baker
The Chemical Weapons Convention prohibits the development, production, acquisition, stockpiling, retention, transfer or use of chemical weapons by Member States. Verification of compliance and investigations into allegations of use require accurate detection of chemical warfare agents (CWAs) and their degradation products. Detection of CWAs such as organophosphorus nerve agents in the environment relies mainly upon the analysis of soil. We now present a method for the detection of the nerve agent VX and its hydrolysis products by gas chromatography and liquid chromatography mass spectrometry of ethanol extracts of contaminated white mustard plants (Sinapis alba) which retained the compounds of interest for up to 45 days...
August 8, 2014: Proceedings. Mathematical, Physical, and Engineering Sciences
M R Gravett, F B Hopkins, A J Self, A J Webb, C M Timperley, J R Riches
In the event of alleged use of organophosphorus nerve agents, all kinds of environmental samples can be received for analysis. These might include decontaminated and charred matter collected from the site of a suspected chemical attack. In other scenarios, such matter might be sampled to confirm the site of a chemical weapon test or clandestine laboratory decontaminated and burned to prevent discovery. To provide an analytical capability for these contingencies, we present a preliminary investigation of the effect of accelerant-based fire and liquid decontamination on soil contaminated with the nerve agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX)...
August 2014: Analytical and Bioanalytical Chemistry
Peter A Baker, Mark N Goltz, Amanda M Schrand, Do Young Yoon, Dong-Shik Kim
Peptide nanotubes (PNTs) encapsulating horseradish peroxidase and surface coated with acetylcholinesterase (AChE) were attached to gold screen printed electrodes to construct a novel gas phase organophosphate (OP) biosensor. When the sensor with the AChE enzyme is put in contact with acetylthiocholine (ATCh), the ATCh is hydrolyzed to produce thiocholine, which is then oxidized by horseradish peroxidase (HRP). Direct electron transfer between HRP and electrode is achieved through PNTs. The signal produced by the electron transfer is measured with cyclic voltammetry (CV)...
November 15, 2014: Biosensors & Bioelectronics
F B Hopkins, M R Gravett, A J Self, M Wang, Hoe-Chee Chua, C Hoe-Chee, H S Nancy Lee, N Lee Hoi Sim, J T A Jones, C M Timperley, J R Riches
Detailed chemical analysis of solutions used to decontaminate chemical warfare agents can be used to support verification and forensic attribution. Decontamination solutions are amongst the most difficult matrices for chemical analysis because of their corrosive and potentially emulsion-based nature. Consequently, there are relatively few publications that report their detailed chemical analysis. This paper describes the application of modern analytical techniques to the analysis of decontamination solutions following decontamination of the chemical warfare agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX)...
August 2014: Analytical and Bioanalytical Chemistry
Ying Lin, Jia Chen, Long Yan, Lei Guo, Bidong Wu, Chunzheng Li, Jianlin Feng, Qin Liu, Jianwei Xie
A simple and sensitive method has been developed and validated for determining ethyl methylphosphonic acid (EMPA), isopropyl methylphosphonic acid (IMPA), isobutyl methylphosphonic acid (iBuMPA), and pinacolyl methylphosphonic acid (PMPA) in human urine using gas chromatography-tandem mass spectrometry (GC-MS/MS) coupled with solid phase derivatization (SPD). These four alkyl methylphosphonic acids (AMPAs) are specific hydrolysis products and biomarkers of exposure to classic organophosphorus (OP) nerve agents VX, sarin, RVX, and soman...
August 2014: Analytical and Bioanalytical Chemistry
Sridhar Chinthakindi, Ajay Purohit, Varoon Singh, D K Dubey, Deepak Pardasani
Present study deals with the on-matrix derivatization-extraction of aminoalcohols and thiodiglycols, which are important precursors and/or degradation products of VX analogues and vesicants class of chemical warfare agents (CWAs). The method involved hexamethyldisilazane (HMDS) mediated in situ silylation of analytes on the soil. Subsequent extraction and gas chromatography-mass spectrometry analysis of derivatized analytes offered better recoveries in comparison to the procedure recommended by the Organization for the Prohibition of Chemical Weapons (OPCW)...
October 11, 2013: Journal of Chromatography. A
Lauren M Petrick, Sara Sabach, Yael Dubowski
Surface degradation of profenofos (PF), a VX nerve gas surrogate, was investigated using in situ photo-oxidation that combines simple instrumentation and ambient gases (O2 and H2O) as a function of exposure conditions ([O3], [OH], UV light λ = 185 and/or 254 nm, relative humidity) and PF film surface density (0.38-3.8 g m(-2)). PF film 0.38 g m(-2) fully degraded after 60 min of exposure to both 254 and 185 nm UV light in humidified air and high ozone. The observed pseudo-first-order surface reaction rate constant (kobs = 0...
August 6, 2013: Environmental Science & Technology
Matthew P Willis, Wesley Gordon, Teri Lalain, Brent Mantooth
A combination of vacuum-based vapor emission measurements with a mass transport model was employed to determine the interaction of chemical warfare agents with various materials, including transport parameters of agents in paints. Accurate determination of mass transport parameters enables the simulation of the chemical agent distribution in a material for decontaminant performance modeling. The evaluation was performed with the chemical warfare agents bis(2-chloroethyl) sulfide (distilled mustard, known as the chemical warfare blister agent HD) and O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX), an organophosphate nerve agent, deposited on to two different types of polyurethane paint coatings...
September 15, 2013: Journal of Hazardous Materials
Adam M Graichen, Richard W Vachet
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...
June 2013: Journal of the American Society for Mass Spectrometry
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"